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* Merge tag 'pull-stable-struct_fd' of ↵Linus Torvalds2024-09-231-15/+15
|\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull 'struct fd' updates from Al Viro: "Just the 'struct fd' layout change, with conversion to accessor helpers" * tag 'pull-stable-struct_fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: add struct fd constructors, get rid of __to_fd() struct fd: representation change introduce fd_file(), convert all accessors to it.
| * introduce fd_file(), convert all accessors to it.Al Viro2024-08-131-15/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For any changes of struct fd representation we need to turn existing accesses to fields into calls of wrappers. Accesses to struct fd::flags are very few (3 in linux/file.h, 1 in net/socket.c, 3 in fs/overlayfs/file.c and 3 more in explicit initializers). Those can be dealt with in the commit converting to new layout; accesses to struct fd::file are too many for that. This commit converts (almost) all of f.file to fd_file(f). It's not entirely mechanical ('file' is used as a member name more than just in struct fd) and it does not even attempt to distinguish the uses in pointer context from those in boolean context; the latter will be eventually turned into a separate helper (fd_empty()). NOTE: mass conversion to fd_empty(), tempting as it might be, is a bad idea; better do that piecewise in commit that convert from fdget...() to CLASS(...). [conflicts in fs/fhandle.c, kernel/bpf/syscall.c, mm/memcontrol.c caught by git; fs/stat.c one got caught by git grep] [fs/xattr.c conflict] Reviewed-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | eventpoll: Annotate data-race of busy_poll_usecsMartin Karsten2024-08-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | A struct eventpoll's busy_poll_usecs field can be modified via a user ioctl at any time. All reads of this field should be annotated with READ_ONCE. Fixes: 85455c795c07 ("eventpoll: support busy poll per epoll instance") Cc: stable@vger.kernel.org Signed-off-by: Martin Karsten <mkarsten@uwaterloo.ca> Link: https://lore.kernel.org/r/20240806123301.167557-1-jdamato@fastly.com Reviewed-by: Joe Damato <jdamato@fastly.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
* | eventpoll: Don't re-zero eventpoll fieldsJoe Damato2024-08-301-5/+0
|/ | | | | | | | | | | | | | | Remove redundant and unnecessary code. ep_alloc uses kzalloc to create struct eventpoll, so there is no need to set fields to defaults of 0. This was accidentally introduced in commit 85455c795c07 ("eventpoll: support busy poll per epoll instance") and expanded on in follow-up commits. Signed-off-by: Joe Damato <jdamato@fastly.com> Link: https://lore.kernel.org/r/20240807105231.179158-1-jdamato@fastly.com Reviewed-by: Martin Karsten <mkarsten@uwaterloo.ca> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
* epoll: be better about file lifetimesLinus Torvalds2024-05-051-1/+37
| | | | | | | | | | | | | | | | | epoll can call out to vfs_poll() with a file pointer that may race with the last 'fput()'. That would make f_count go down to zero, and while the ep->mtx locking means that the resulting file pointer tear-down will be blocked until the poll returns, it means that f_count is already dead, and any use of it won't actually get a reference to the file any more: it's dead regardless. Make sure we have a valid ref on the file pointer before we call down to vfs_poll() from the epoll routines. Link: https://lore.kernel.org/lkml/0000000000002d631f0615918f1e@google.com/ Reported-by: syzbot+045b454ab35fd82a35fb@syzkaller.appspotmail.com Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'net-next-6.9' of ↵Linus Torvalds2024-03-131-7/+124
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: "Core & protocols: - Large effort by Eric to lower rtnl_lock pressure and remove locks: - Make commonly used parts of rtnetlink (address, route dumps etc) lockless, protected by RCU instead of rtnl_lock. - Add a netns exit callback which already holds rtnl_lock, allowing netns exit to take rtnl_lock once in the core instead of once for each driver / callback. - Remove locks / serialization in the socket diag interface. - Remove 6 calls to synchronize_rcu() while holding rtnl_lock. - Remove the dev_base_lock, depend on RCU where necessary. - Support busy polling on a per-epoll context basis. Poll length and budget parameters can be set independently of system defaults. - Introduce struct net_hotdata, to make sure read-mostly global config variables fit in as few cache lines as possible. - Add optional per-nexthop statistics to ease monitoring / debug of ECMP imbalance problems. - Support TCP_NOTSENT_LOWAT in MPTCP. - Ensure that IPv6 temporary addresses' preferred lifetimes are long enough, compared to other configured lifetimes, and at least 2 sec. - Support forwarding of ICMP Error messages in IPSec, per RFC 4301. - Add support for the independent control state machine for bonding per IEEE 802.1AX-2008 5.4.15 in addition to the existing coupled control state machine. - Add "network ID" to MCTP socket APIs to support hosts with multiple disjoint MCTP networks. - Re-use the mono_delivery_time skbuff bit for packets which user space wants to be sent at a specified time. Maintain the timing information while traversing veth links, bridge etc. - Take advantage of MSG_SPLICE_PAGES for RxRPC DATA and ACK packets. - Simplify many places iterating over netdevs by using an xarray instead of a hash table walk (hash table remains in place, for use on fastpaths). - Speed up scanning for expired routes by keeping a dedicated list. - Speed up "generic" XDP by trying harder to avoid large allocations. - Support attaching arbitrary metadata to netconsole messages. Things we sprinkled into general kernel code: - Enforce VM_IOREMAP flag and range in ioremap_page_range and introduce VM_SPARSE kind and vm_area_[un]map_pages (used by bpf_arena). - Rework selftest harness to enable the use of the full range of ksft exit code (pass, fail, skip, xfail, xpass). Netfilter: - Allow userspace to define a table that is exclusively owned by a daemon (via netlink socket aliveness) without auto-removing this table when the userspace program exits. Such table gets marked as orphaned and a restarting management daemon can re-attach/regain ownership. - Speed up element insertions to nftables' concatenated-ranges set type. Compact a few related data structures. BPF: - Add BPF token support for delegating a subset of BPF subsystem functionality from privileged system-wide daemons such as systemd through special mount options for userns-bound BPF fs to a trusted & unprivileged application. - Introduce bpf_arena which is sparse shared memory region between BPF program and user space where structures inside the arena can have pointers to other areas of the arena, and pointers work seamlessly for both user-space programs and BPF programs. - Introduce may_goto instruction that is a contract between the verifier and the program. The verifier allows the program to loop assuming it's behaving well, but reserves the right to terminate it. - Extend the BPF verifier to enable static subprog calls in spin lock critical sections. - Support registration of struct_ops types from modules which helps projects like fuse-bpf that seeks to implement a new struct_ops type. - Add support for retrieval of cookies for perf/kprobe multi links. - Support arbitrary TCP SYN cookie generation / validation in the TC layer with BPF to allow creating SYN flood handling in BPF firewalls. - Add code generation to inline the bpf_kptr_xchg() helper which improves performance when stashing/popping the allocated BPF objects. Wireless: - Add SPP (signaling and payload protected) AMSDU support. - Support wider bandwidth OFDMA, as required for EHT operation. Driver API: - Major overhaul of the Energy Efficient Ethernet internals to support new link modes (2.5GE, 5GE), share more code between drivers (especially those using phylib), and encourage more uniform behavior. Convert and clean up drivers. - Define an API for querying per netdev queue statistics from drivers. - IPSec: account in global stats for fully offloaded sessions. - Create a concept of Ethernet PHY Packages at the Device Tree level, to allow parameterizing the existing PHY package code. - Enable Rx hashing (RSS) on GTP protocol fields. Misc: - Improvements and refactoring all over networking selftests. - Create uniform module aliases for TC classifiers, actions, and packet schedulers to simplify creating modprobe policies. - Address all missing MODULE_DESCRIPTION() warnings in networking. - Extend the Netlink descriptions in YAML to cover message encapsulation or "Netlink polymorphism", where interpretation of nested attributes depends on link type, classifier type or some other "class type". Drivers: - Ethernet high-speed NICs: - Add a new driver for Marvell's Octeon PCI Endpoint NIC VF. - Intel (100G, ice, idpf): - support E825-C devices - nVidia/Mellanox: - support devices with one port and multiple PCIe links - Broadcom (bnxt): - support n-tuple filters - support configuring the RSS key - Wangxun (ngbe/txgbe): - implement irq_domain for TXGBE's sub-interrupts - Pensando/AMD: - support XDP - optimize queue submission and wakeup handling (+17% bps) - optimize struct layout, saving 28% of memory on queues - Ethernet NICs embedded and virtual: - Google cloud vNIC: - refactor driver to perform memory allocations for new queue config before stopping and freeing the old queue memory - Synopsys (stmmac): - obey queueMaxSDU and implement counters required by 802.1Qbv - Renesas (ravb): - support packet checksum offload - suspend to RAM and runtime PM support - Ethernet switches: - nVidia/Mellanox: - support for nexthop group statistics - Microchip: - ksz8: implement PHY loopback - add support for KSZ8567, a 7-port 10/100Mbps switch - PTP: - New driver for RENESAS FemtoClock3 Wireless clock generator. - Support OCP PTP cards designed and built by Adva. - CAN: - Support recvmsg() flags for own, local and remote traffic on CAN BCM sockets. - Support for esd GmbH PCIe/402 CAN device family. - m_can: - Rx/Tx submission coalescing - wake on frame Rx - WiFi: - Intel (iwlwifi): - enable signaling and payload protected A-MSDUs - support wider-bandwidth OFDMA - support for new devices - bump FW API to 89 for AX devices; 90 for BZ/SC devices - MediaTek (mt76): - mt7915: newer ADIE version support - mt7925: radio temperature sensor support - Qualcomm (ath11k): - support 6 GHz station power modes: Low Power Indoor (LPI), Standard Power) SP and Very Low Power (VLP) - QCA6390 & WCN6855: support 2 concurrent station interfaces - QCA2066 support - Qualcomm (ath12k): - refactoring in preparation for Multi-Link Operation (MLO) support - 1024 Block Ack window size support - firmware-2.bin support - support having multiple identical PCI devices (firmware needs to have ATH12K_FW_FEATURE_MULTI_QRTR_ID) - QCN9274: support split-PHY devices - WCN7850: enable Power Save Mode in station mode - WCN7850: P2P support - RealTek: - rtw88: support for more rtw8811cu and rtw8821cu devices - rtw89: support SCAN_RANDOM_SN and SET_SCAN_DWELL - rtlwifi: speed up USB firmware initialization - rtwl8xxxu: - RTL8188F: concurrent interface support - Channel Switch Announcement (CSA) support in AP mode - Broadcom (brcmfmac): - per-vendor feature support - per-vendor SAE password setup - DMI nvram filename quirk for ACEPC W5 Pro" * tag 'net-next-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2255 commits) nexthop: Fix splat with CONFIG_DEBUG_PREEMPT=y nexthop: Fix out-of-bounds access during attribute validation nexthop: Only parse NHA_OP_FLAGS for dump messages that require it nexthop: Only parse NHA_OP_FLAGS for get messages that require it bpf: move sleepable flag from bpf_prog_aux to bpf_prog bpf: hardcode BPF_PROG_PACK_SIZE to 2MB * num_possible_nodes() selftests/bpf: Add kprobe multi triggering benchmarks ptp: Move from simple ida to xarray vxlan: Remove generic .ndo_get_stats64 vxlan: Do not alloc tstats manually devlink: Add comments to use netlink gen tool nfp: flower: handle acti_netdevs allocation failure net/packet: Add getsockopt support for PACKET_COPY_THRESH net/netlink: Add getsockopt support for NETLINK_LISTEN_ALL_NSID selftests/bpf: Add bpf_arena_htab test. selftests/bpf: Add bpf_arena_list test. selftests/bpf: Add unit tests for bpf_arena_alloc/free_pages bpf: Add helper macro bpf_addr_space_cast() libbpf: Recognize __arena global variables. bpftool: Recognize arena map type ...
| * eventpoll: Add epoll ioctl for epoll_paramsJoe Damato2024-02-141-0/+73
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add an ioctl for getting and setting epoll_params. User programs can use this ioctl to get and set the busy poll usec time, packet budget, and prefer busy poll params for a specific epoll context. Parameters are limited: - busy_poll_usecs is limited to <= s32_max - busy_poll_budget is limited to <= NAPI_POLL_WEIGHT by unprivileged users (!capable(CAP_NET_ADMIN)) - prefer_busy_poll must be 0 or 1 - __pad must be 0 Signed-off-by: Joe Damato <jdamato@fastly.com> Acked-by: Stanislav Fomichev <sdf@google.com> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * eventpoll: Add per-epoll prefer busy poll optionJoe Damato2024-02-141-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When using epoll-based busy poll, the prefer_busy_poll option is hardcoded to false. Users may want to enable prefer_busy_poll to be used in conjunction with gro_flush_timeout and defer_hard_irqs_count to keep device IRQs masked. Other busy poll methods allow enabling or disabling prefer busy poll via SO_PREFER_BUSY_POLL, but epoll-based busy polling uses a hardcoded value. Fix this edge case by adding support for a per-epoll context prefer_busy_poll option. The default is false, as it was hardcoded before this change. Signed-off-by: Joe Damato <jdamato@fastly.com> Acked-by: Stanislav Fomichev <sdf@google.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * eventpoll: Add per-epoll busy poll packet budgetJoe Damato2024-02-141-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When using epoll-based busy poll, the packet budget is hardcoded to BUSY_POLL_BUDGET (8). Users may desire larger busy poll budgets, which can potentially increase throughput when busy polling under high network load. Other busy poll methods allow setting the busy poll budget via SO_BUSY_POLL_BUDGET, but epoll-based busy polling uses a hardcoded value. Fix this edge case by adding support for a per-epoll context busy poll packet budget. If not specified, the default value (BUSY_POLL_BUDGET) is used. Signed-off-by: Joe Damato <jdamato@fastly.com> Acked-by: Stanislav Fomichev <sdf@google.com> Reviewed-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
| * eventpoll: support busy poll per epoll instanceJoe Damato2024-02-141-5/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow busy polling on a per-epoll context basis. The per-epoll context usec timeout value is preferred, but the pre-existing system wide sysctl value is still supported if it specified. busy_poll_usecs is a u32, but in a follow up patch the ioctl provided to the user only allows setting a value from 0 to S32_MAX. Signed-off-by: Joe Damato <jdamato@fastly.com> Acked-by: Stanislav Fomichev <sdf@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* | eventpoll: prefer kfree_rcu() in __ep_remove()Dmitry Antipov2024-02-221-7/+1
| | | | | | | | | | | | | | | | | | | | | | In '__ep_remove()', prefer 'kfree_rcu()' over 'call_rcu()' with dummy 'epi_rcu_free()' callback. This follows commit d0089603fa7a ("fs: prefer kfree_rcu() in fasync_remove_entry()") and should not be backported to stable as well. Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru> Link: https://lore.kernel.org/r/20240221112205.48389-2-dmantipov@yandex.ru Signed-off-by: Christian Brauner <brauner@kernel.org>
* | epoll: Remove ep_scan_ready_list() in commentsHuang Xiaojia2024-02-061-4/+4
|/ | | | | | | | | | | | Since commit 443f1a042233 ("lift the calls of ep_send_events_proc() into the callers"), ep_scan_ready_list() has been removed. But there are still several in comments. All of them should be replaced with other caller functions. Signed-off-by: Huang Xiaojia <huangxiaojia2@huawei.com> Link: https://lore.kernel.org/r/20240206014353.4191262-1-huangxiaojia2@huawei.com Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
* fs: Remove the now superfluous sentinel elements from ctl_table arrayJoel Granados2023-12-281-1/+0
| | | | | | | | | | | | | | | | | | | This commit comes at the tail end of a greater effort to remove the empty elements at the end of the ctl_table arrays (sentinels) which will reduce the overall build time size of the kernel and run time memory bloat by ~64 bytes per sentinel (further information Link : https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/) Remove sentinel elements ctl_table struct. Special attention was placed in making sure that an empty directory for fs/verity was created when CONFIG_FS_VERITY_BUILTIN_SIGNATURES is not defined. In this case we use the register sysctl call that expects a size. Signed-off-by: Joel Granados <j.granados@samsung.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
* treewide: mark stuff as __ro_after_initAlexey Dobriyan2023-10-181-3/+3
| | | | | | | | | | | | | __read_mostly predates __ro_after_init. Many variables which are marked __read_mostly should have been __ro_after_init from day 1. Also, mark some stuff as "const" and "__init" while I'm at it. [akpm@linux-foundation.org: revert sysctl_nr_open_min, sysctl_nr_open_max changes due to arm warning] [akpm@linux-foundation.org: coding-style cleanups] Link: https://lkml.kernel.org/r/4f6bb9c0-abba-4ee4-a7aa-89265e886817@p183 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* epoll: simplify ep_alloc()Zhen Lei2023-07-261-10/+2
| | | | | | | | | The get_current_user() does not fail, and moving it after kzalloc() can simplify the code a bit. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Message-Id: <20230726032135.933-1-thunder.leizhen@huaweicloud.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
* Merge tag 'v6.5/vfs.misc' of ↵Linus Torvalds2023-06-261-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull misc vfs updates from Christian Brauner: "Miscellaneous features, cleanups, and fixes for vfs and individual fs Features: - Use mode 0600 for file created by cachefilesd so it can be run by unprivileged users. This aligns them with directories which are already created with mode 0700 by cachefilesd - Reorder a few members in struct file to prevent some false sharing scenarios - Indicate that an eventfd is used a semaphore in the eventfd's fdinfo procfs file - Add a missing uapi header for eventfd exposing relevant uapi defines - Let the VFS protect transitions of a superblock from read-only to read-write in addition to the protection it already provides for transitions from read-write to read-only. Protecting read-only to read-write transitions allows filesystems such as ext4 to perform internal writes, keeping writers away until the transition is completed Cleanups: - Arnd removed the architecture specific arch_report_meminfo() prototypes and added a generic one into procfs.h. Note, we got a report about a warning in amdpgpu codepaths that suggested this was bisectable to this change but we concluded it was a false positive - Remove unused parameters from split_fs_names() - Rename put_and_unmap_page() to unmap_and_put_page() to let the name reflect the order of the cleanup operation that has to unmap before the actual put - Unexport buffer_check_dirty_writeback() as it is not used outside of block device aops - Stop allocating aio rings from highmem - Protecting read-{only,write} transitions in the VFS used open-coded barriers in various places. Replace them with proper little helpers and document both the helpers and all barrier interactions involved when transitioning between read-{only,write} states - Use flexible array members in old readdir codepaths Fixes: - Use the correct type __poll_t for epoll and eventfd - Replace all deprecated strlcpy() invocations, whose return value isn't checked with an equivalent strscpy() call - Fix some kernel-doc warnings in fs/open.c - Reduce the stack usage in jffs2's xattr codepaths finally getting rid of this: fs/jffs2/xattr.c:887:1: error: the frame size of 1088 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] royally annoying compilation warning - Use __FMODE_NONOTIFY instead of FMODE_NONOTIFY where an int and not fmode_t is required to avoid fmode_t to integer degradation warnings - Create coredumps with O_WRONLY instead of O_RDWR. There's a long explanation in that commit how O_RDWR is actually a bug which we found out with the help of Linus and git archeology - Fix "no previous prototype" warnings in the pipe codepaths - Add overflow calculations for remap_verify_area() as a signed addition overflow could be triggered in xfstests - Fix a null pointer dereference in sysv - Use an unsigned variable for length calculations in jfs avoiding compilation warnings with gcc 13 - Fix a dangling pipe pointer in the watch queue codepath - The legacy mount option parser provided as a fallback by the VFS for filesystems not yet converted to the new mount api did prefix the generated mount option string with a leading ',' causing issues for some filesystems - Fix a repeated word in a comment in fs.h - autofs: Update the ctime when mtime is updated as mandated by POSIX" * tag 'v6.5/vfs.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (27 commits) readdir: Replace one-element arrays with flexible-array members fs: Provide helpers for manipulating sb->s_readonly_remount fs: Protect reconfiguration of sb read-write from racing writes eventfd: add a uapi header for eventfd userspace APIs autofs: set ctime as well when mtime changes on a dir eventfd: show the EFD_SEMAPHORE flag in fdinfo fs/aio: Stop allocating aio rings from HIGHMEM fs: Fix comment typo fs: unexport buffer_check_dirty_writeback fs: avoid empty option when generating legacy mount string watch_queue: prevent dangling pipe pointer fs.h: Optimize file struct to prevent false sharing highmem: Rename put_and_unmap_page() to unmap_and_put_page() cachefiles: Allow the cache to be non-root init: remove unused names parameter in split_fs_names() jfs: Use unsigned variable for length calculations fs/sysv: Null check to prevent null-ptr-deref bug fs: use UB-safe check for signed addition overflow in remap_verify_area procfs: consolidate arch_report_meminfo declaration fs: pipe: reveal missing function protoypes ...
| * fs: use correct __poll_t typeMin-Hua Chen2023-05-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Fix the following sparse warnings by using __poll_t instead of unsigned type. fs/eventpoll.c:541:9: sparse: warning: restricted __poll_t degrades to integer fs/eventfd.c:67:17: sparse: warning: restricted __poll_t degrades to integer Signed-off-by: Min-Hua Chen <minhuadotchen@gmail.com> Message-Id: <20230511164628.336586-1-minhuadotchen@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
* | epoll: ep_autoremove_wake_function should use list_del_init_carefulBenjamin Segall2023-06-121-1/+5
|/ | | | | | | | | | | | | | | | autoremove_wake_function uses list_del_init_careful, so should epoll's more aggressive variant. It only doesn't because it was copied from an older wait.c rather than the most recent. [bsegall@google.com: add comment] Link: https://lkml.kernel.org/r/xm26bki0ulsr.fsf_-_@google.com Link: https://lkml.kernel.org/r/xm26pm6hvfer.fsf@google.com Fixes: a16ceb139610 ("epoll: autoremove wakers even more aggressively") Signed-off-by: Ben Segall <bsegall@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* Merge tag 'mm-nonmm-stable-2023-04-27-16-01' of ↵Linus Torvalds2023-04-281-82/+133
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull non-MM updates from Andrew Morton: "Mainly singleton patches all over the place. Series of note are: - updates to scripts/gdb from Glenn Washburn - kexec cleanups from Bjorn Helgaas" * tag 'mm-nonmm-stable-2023-04-27-16-01' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (50 commits) mailmap: add entries for Paul Mackerras libgcc: add forward declarations for generic library routines mailmap: add entry for Oleksandr ocfs2: reduce ioctl stack usage fs/proc: add Kthread flag to /proc/$pid/status ia64: fix an addr to taddr in huge_pte_offset() checkpatch: introduce proper bindings license check epoll: rename global epmutex scripts/gdb: add GDB convenience functions $lx_dentry_name() and $lx_i_dentry() scripts/gdb: create linux/vfs.py for VFS related GDB helpers uapi/linux/const.h: prefer ISO-friendly __typeof__ delayacct: track delays from IRQ/SOFTIRQ scripts/gdb: timerlist: convert int chunks to str scripts/gdb: print interrupts scripts/gdb: raise error with reduced debugging information scripts/gdb: add a Radix Tree Parser lib/rbtree: use '+' instead of '|' for setting color. proc/stat: remove arch_idle_time() checkpatch: check for misuse of the link tags checkpatch: allow Closes tags with links ...
| * epoll: rename global epmutexDavidlohr Bueso2023-04-191-11/+11
| | | | | | | | | | | | | | | | | | | | | | | | As of 4f04cbaf128 ("epoll: use refcount to reduce ep_mutex contention"), this lock is now specific to nesting cases - inserting an epoll fd onto another epoll fd. Rename the lock to be less generic. Link: https://lkml.kernel.org/r/20230411234159.20421-1-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| * epoll: use refcount to reduce ep_mutex contentionPaolo Abeni2023-04-081-72/+123
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We are observing huge contention on the epmutex during an http connection/rate test: 83.17% 0.25% nginx [kernel.kallsyms] [k] entry_SYSCALL_64_after_hwframe [...] |--66.96%--__fput |--60.04%--eventpoll_release_file |--58.41%--__mutex_lock.isra.6 |--56.56%--osq_lock The application is multi-threaded, creates a new epoll entry for each incoming connection, and does not delete it before the connection shutdown - that is, before the connection's fd close(). Many different threads compete frequently for the epmutex lock, affecting the overall performance. To reduce the contention this patch introduces explicit reference counting for the eventpoll struct. Each registered event acquires a reference, and references are released at ep_remove() time. The eventpoll struct is released by whoever - among EP file close() and and the monitored file close() drops its last reference. Additionally, this introduces a new 'dying' flag to prevent races between the EP file close() and the monitored file close(). ep_eventpoll_release() marks, under f_lock spinlock, each epitem as dying before removing it, while EP file close() does not touch dying epitems. The above is needed as both close operations could run concurrently and drop the EP reference acquired via the epitem entry. Without the above flag, the monitored file close() could reach the EP struct via the epitem list while the epitem is still listed and then try to put it after its disposal. An alternative could be avoiding touching the references acquired via the epitems at EP file close() time, but that could leave the EP struct alive for potentially unlimited time after EP file close(), with nasty side effects. With all the above in place, we can drop the epmutex usage at disposal time. Overall this produces a significant performance improvement in the mentioned connection/rate scenario: the mutex operations disappear from the topmost offenders in the perf report, and the measured connections/rate grows by ~60%. To make the change more readable this additionally renames ep_free() to ep_clear_and_put(), and moves the actual memory cleanup in a separate ep_free() helper. Link: https://lkml.kernel.org/r/4a57788dcaf28f5eb4f8dfddcc3a8b172a7357bb.1679504153.git.pabeni@redhat.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Co-developed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Tested-by: Xiumei Mu <xmu@redhiat.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Jacob Keller <jacob.e.keller@intel.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* | Merge tag 'asm-generic-6.4' of ↵Linus Torvalds2023-04-251-0/+13
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic Pull asm-generic updates from Arnd Bergmann: "These are various cleanups, fixing a number of uapi header files to no longer reference CONFIG_* symbols, and one patch that introduces the new CONFIG_HAS_IOPORT symbol for architectures that provide working inb()/outb() macros, as a preparation for adding driver dependencies on those in the following release" * tag 'asm-generic-6.4' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: Kconfig: introduce HAS_IOPORT option and select it as necessary scripts: Update the CONFIG_* ignore list in headers_install.sh pktcdvd: Remove CONFIG_CDROM_PKTCDVD_WCACHE from uapi header Move bp_type_idx to include/linux/hw_breakpoint.h Move ep_take_care_of_epollwakeup() to fs/eventpoll.c Move COMPAT_ATM_ADDPARTY to net/atm/svc.c
| * | Move ep_take_care_of_epollwakeup() to fs/eventpoll.cPalmer Dabbelt2023-03-101-0/+13
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This doesn't make any sense to expose to userspace, so it's been moved to the one user. This was introduced by commit 95f19f658ce1 ("epoll: drop EPOLLWAKEUP if PM_SLEEP is disabled"). Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com> Reviewed-by: Andrew Waterman <waterman@eecs.berkeley.edu> Reviewed-by: Albert Ou <aou@eecs.berkeley.edu> Message-Id: <1447119071-19392-7-git-send-email-palmer@dabbelt.com> [thuth: Rebased to fix contextual conflicts] Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* / eventpoll: align comment with nested epoll limitationChangcheng Liu2023-03-131-2/+2
|/ | | | | | | fix comment in commit 02edc6fc4d5f ("epoll: comment the funky #ifdef") Signed-off-by: Liu, Changcheng <changchengx.liu@outlook.com> Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
* eventpoll: add EPOLL_URING_WAKE poll wakeup flagJens Axboe2022-11-211-8/+10
| | | | | | | | | | | | | | | | We can have dependencies between epoll and io_uring. Consider an epoll context, identified by the epfd file descriptor, and an io_uring file descriptor identified by iofd. If we add iofd to the epfd context, and arm a multishot poll request for epfd with iofd, then the multishot poll request will repeatedly trigger and generate events until terminated by CQ ring overflow. This isn't a desired behavior. Add EPOLL_URING so that io_uring can pass it in as part of the poll wakeup key, and io_uring can check for that to detect a potential recursive invocation. Cc: stable@vger.kernel.org # 6.0 Signed-off-by: Jens Axboe <axboe@kernel.dk>
* epoll: use try_cmpxchg in list_add_tail_locklessUros Bizjak2022-09-121-1/+1
| | | | | | | | | | | | | | Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in list_add_tail_lockless. x86 CMPXCHG instruction returns success in ZF flag, so this change saves a compare after cmpxchg (and related move instruction in front of cmpxchg). No functional change intended. Link: https://lkml.kernel.org/r/20220714173255.12987-1-ubizjak@gmail.com Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* epoll: autoremove wakers even more aggressivelyBenjamin Segall2022-07-181-0/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a process is killed or otherwise exits while having active network connections and many threads waiting on epoll_wait, the threads will all be woken immediately, but not removed from ep->wq. Then when network traffic scans ep->wq in wake_up, every wakeup attempt will fail, and will not remove the entries from the list. This means that the cost of the wakeup attempt is far higher than usual, does not decrease, and this also competes with the dying threads trying to actually make progress and remove themselves from the wq. Handle this by removing visited epoll wq entries unconditionally, rather than only when the wakeup succeeds - the structure of ep_poll means that the only potential loss is the timed_out->eavail heuristic, which now can race and result in a redundant ep_send_events attempt. (But only when incoming data and a timeout actually race, not on every timeout) Shakeel added: : We are seeing this issue in production with real workloads and it has : caused hard lockups. Particularly network heavy workloads with a lot : of threads in epoll_wait() can easily trigger this issue if they get : killed (oom-killed in our case). Link: https://lkml.kernel.org/r/xm26fsjotqda.fsf@google.com Signed-off-by: Ben Segall <bsegall@google.com> Tested-by: Shakeel Butt <shakeelb@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Roman Penyaev <rpenyaev@suse.de> Cc: Jason Baron <jbaron@akamai.com> Cc: Khazhismel Kumykov <khazhy@google.com> Cc: Heiher <r@hev.cc> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* eventpoll: simplify sysctl declaration with register_sysctl()Xiaoming Ni2022-01-221-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel/sysctl.c is a kitchen sink where everyone leaves their dirty dishes, this makes it very difficult to maintain. To help with this maintenance let's start by moving sysctls to places where they actually belong. The proc sysctl maintainers do not want to know what sysctl knobs you wish to add for your own piece of code, we just care about the core logic. So move the epoll_table sysctl to fs/eventpoll.c and use register_sysctl(). Link: https://lkml.kernel.org/r/20211123202422.819032-9-mcgrof@kernel.org Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Amir Goldstein <amir73il@gmail.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Antti Palosaari <crope@iki.fi> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Clemens Ladisch <clemens@ladisch.de> Cc: David Airlie <airlied@linux.ie> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Joel Becker <jlbec@evilplan.org> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Julia Lawall <julia.lawall@inria.fr> Cc: Kees Cook <keescook@chromium.org> Cc: Lukas Middendorf <kernel@tuxforce.de> Cc: Mark Fasheh <mark@fasheh.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Phillip Potter <phil@philpotter.co.uk> Cc: Qing Wang <wangqing@vivo.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Sebastian Reichel <sre@kernel.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Stephen Kitt <steve@sk2.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Douglas Gilbert <dgilbert@interlog.com> Cc: James E.J. Bottomley <jejb@linux.ibm.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds2021-09-091-3/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull ARM development updates from Russell King: - Rename "mod_init" and "mod_exit" so that initcall debug output is actually useful (Randy Dunlap) - Update maintainers entries for linux-arm-kernel to indicate it is moderated for non-subscribers (Randy Dunlap) - Move install rules to arch/arm/Makefile (Masahiro Yamada) - Drop unnecessary ARCH_NR_GPIOS definition (Linus Walleij) - Don't warn about atags_to_fdt() stack size (David Heidelberg) - Speed up unaligned copy_{from,to}_kernel_nofault (Arnd Bergmann) - Get rid of set_fs() usage (Arnd Bergmann) - Remove checks for GCC prior to v4.6 (Geert Uytterhoeven) * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 9118/1: div64: Remove always-true __div64_const32_is_OK() duplicate ARM: 9117/1: asm-generic: div64: Remove always-true __div64_const32_is_OK() ARM: 9116/1: unified: Remove check for gcc < 4 ARM: 9110/1: oabi-compat: fix oabi epoll sparse warning ARM: 9113/1: uaccess: remove set_fs() implementation ARM: 9112/1: uaccess: add __{get,put}_kernel_nofault ARM: 9111/1: oabi-compat: rework fcntl64() emulation ARM: 9114/1: oabi-compat: rework sys_semtimedop emulation ARM: 9108/1: oabi-compat: rework epoll_wait/epoll_pwait emulation ARM: 9107/1: syscall: always store thread_info->abi_syscall ARM: 9109/1: oabi-compat: add epoll_pwait handler ARM: 9106/1: traps: use get_kernel_nofault instead of set_fs() ARM: 9115/1: mm/maccess: fix unaligned copy_{from,to}_kernel_nofault ARM: 9105/1: atags_to_fdt: don't warn about stack size ARM: 9103/1: Drop ARCH_NR_GPIOS definition ARM: 9102/1: move theinstall rules to arch/arm/Makefile ARM: 9100/1: MAINTAINERS: mark all linux-arm-kernel@infradead list as moderated ARM: 9099/1: crypto: rename 'mod_init' & 'mod_exit' functions to be module-specific
| * ARM: 9108/1: oabi-compat: rework epoll_wait/epoll_pwait emulationArnd Bergmann2021-08-201-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The epoll_wait() system call wrapper is one of the remaining users of the set_fs() infrasturcture for Arm. Changing it to not require set_fs() is rather complex unfortunately. The approach I'm taking here is to allow architectures to override the code that copies the output to user space, and let the oabi-compat implementation check whether it is getting called from an EABI or OABI system call based on the thread_info->syscall value. The in_oabi_syscall() check here mirrors the in_compat_syscall() and in_x32_syscall() helpers for 32-bit compat implementations on other architectures. Overall, the amount of code goes down, at least with the newly added sys_oabi_epoll_pwait() helper getting removed again. The downside is added complexity in the source code for the native implementation. There should be no difference in runtime performance except for Arm kernels with CONFIG_OABI_COMPAT enabled that now have to go through an external function call to check which of the two variants to use. Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* | fs/epoll: use a per-cpu counter for user's watches countNicholas Piggin2021-09-081-8/+10
|/ | | | | | | | | | | | | | | | | | | | | This counter tracks the number of watches a user has, to compare against the 'max_user_watches' limit. This causes a scalability bottleneck on SPECjbb2015 on large systems as there is only one user. Changing to a per-cpu counter increases throughput of the benchmark by about 30% on a 16-socket, > 1000 thread system. [rdunlap@infradead.org: fix build errors in kernel/user.c when CONFIG_EPOLL=n] [npiggin@gmail.com: move ifdefs into wrapper functions, slightly improve panic message] Link: https://lkml.kernel.org/r/1628051945.fens3r99ox.astroid@bobo.none [akpm@linux-foundation.org: tweak user_epoll_alloc(), per Guenter] Link: https://lkml.kernel.org/r/20210804191421.GA1900577@roeck-us.net Link: https://lkml.kernel.org/r/20210802032013.2751916-1-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reported-by: Anton Blanchard <anton@ozlabs.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/epoll: restore waking from ep_done_scan()Davidlohr Bueso2021-05-071-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | Commit 339ddb53d373 ("fs/epoll: remove unnecessary wakeups of nested epoll") changed the userspace visible behavior of exclusive waiters blocked on a common epoll descriptor upon a single event becoming ready. Previously, all tasks doing epoll_wait would awake, and now only one is awoken, potentially causing missed wakeups on applications that rely on this behavior, such as Apache Qpid. While the aforementioned commit aims at having only a wakeup single path in ep_poll_callback (with the exceptions of epoll_ctl cases), we need to restore the wakeup in what was the old ep_scan_ready_list() such that the next thread can be awoken, in a cascading style, after the waker's corresponding ep_send_events(). Link: https://lkml.kernel.org/r/20210405231025.33829-3-dave@stgolabs.net Fixes: 339ddb53d373 ("fs/epoll: remove unnecessary wakeups of nested epoll") Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Jason Baron <jbaron@akamai.com> Cc: Roman Penyaev <rpenyaev@suse.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: eventpoll: fix comments & kernel-doc notationRandy Dunlap2021-03-071-26/+26
| | | | | | | | | | | | | | | | | | | | | | Use the documented kernel-doc format for function Return: descriptions. Begin constant values in kernel-doc comments with '%'. Remove kernel-doc "/**" from 2 functions that are not documented with kernel-doc notation. Fix typos, punctuation, & grammar. Also fix a few kernel-doc warnings: ../fs/eventpoll.c:1883: warning: Function parameter or member 'ep' not described in 'ep_loop_check_proc' ../fs/eventpoll.c:1883: warning: Excess function parameter 'priv' description in 'ep_loop_check_proc' ../fs/eventpoll.c:1932: warning: Function parameter or member 'ep' not described in 'ep_loop_check' ../fs/eventpoll.c:1932: warning: Excess function parameter 'from' description in 'ep_loop_check' Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* kcmp: Support selection of SYS_kcmp without CHECKPOINT_RESTOREChris Wilson2021-02-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Userspace has discovered the functionality offered by SYS_kcmp and has started to depend upon it. In particular, Mesa uses SYS_kcmp for os_same_file_description() in order to identify when two fd (e.g. device or dmabuf) point to the same struct file. Since they depend on it for core functionality, lift SYS_kcmp out of the non-default CONFIG_CHECKPOINT_RESTORE into the selectable syscall category. Rasmus Villemoes also pointed out that systemd uses SYS_kcmp to deduplicate the per-service file descriptor store. Note that some distributions such as Ubuntu are already enabling CHECKPOINT_RESTORE in their configs and so, by extension, SYS_kcmp. References: https://gitlab.freedesktop.org/drm/intel/-/issues/3046 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will Drewry <wad@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Airlie <airlied@gmail.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: stable@vger.kernel.org Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> # DRM depends on kcmp Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> # systemd uses kcmp Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20210205220012.1983-1-chris@chris-wilson.co.uk
* epoll: add syscall epoll_pwait2Willem de Bruijn2020-12-191-14/+73
| | | | | | | | | | | | | | | | | | | | | | | | | | | Add syscall epoll_pwait2, an epoll_wait variant with nsec resolution that replaces int timeout with struct timespec. It is equivalent otherwise. int epoll_pwait2(int fd, struct epoll_event *events, int maxevents, const struct timespec *timeout, const sigset_t *sigset); The underlying hrtimer is already programmed with nsec resolution. pselect and ppoll also set nsec resolution timeout with timespec. The sigset_t in epoll_pwait has a compat variant. epoll_pwait2 needs the same. For timespec, only support this new interface on 2038 aware platforms that define __kernel_timespec_t. So no CONFIG_COMPAT_32BIT_TIME. Link: https://lkml.kernel.org/r/20201121144401.3727659-3-willemdebruijn.kernel@gmail.com Signed-off-by: Willem de Bruijn <willemb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* epoll: convert internal api to timespec64Willem de Bruijn2020-12-191-20/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "add epoll_pwait2 syscall", v4. Enable nanosecond timeouts for epoll. Analogous to pselect and ppoll, introduce an epoll_wait syscall variant that takes a struct timespec instead of int timeout. This patch (of 4): Make epoll more consistent with select/poll: pass along the timeout as timespec64 pointer. In anticipation of additional changes affecting all three polling mechanisms: - add epoll_pwait2 syscall with timespec semantics, and share poll_select_set_timeout implementation. - compute slack before conversion to absolute time, to save one ktime_get_ts64 call. Link: https://lkml.kernel.org/r/20201121144401.3727659-1-willemdebruijn.kernel@gmail.com Link: https://lkml.kernel.org/r/20201121144401.3727659-2-willemdebruijn.kernel@gmail.com Signed-off-by: Willem de Bruijn <willemb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* epoll: eliminate unnecessary lock for zero timeoutSoheil Hassas Yeganeh2020-12-191-13/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | We call ep_events_available() under lock when timeout is 0, and then call it without locks in the loop for the other cases. Instead, call ep_events_available() without lock for all cases. For non-zero timeouts, we will recheck after adding the thread to the wait queue. For zero timeout cases, by definition, user is opportunistically polling and will have to call epoll_wait again in the future. Note that this lock was kept in c5a282e9635e9 because the whole loop was historically under lock. This patch results in a 1% CPU/RPC reduction in RPC benchmarks. Link: https://lkml.kernel.org/r/20201106231635.3528496-9-soheil.kdev@gmail.com Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Suggested-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Khazhismel Kumykov <khazhy@google.com> Cc: Guantao Liu <guantaol@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* epoll: replace gotos with a proper loopSoheil Hassas Yeganeh2020-12-191-21/+21
| | | | | | | | | | | | | | | | | | The existing loop is pointless, and the labels make it really hard to follow the structure. Replace that control structure with a simple loop that returns when there are new events, there is a signal, or the thread has timed out. Link: https://lkml.kernel.org/r/20201106231635.3528496-8-soheil.kdev@gmail.com Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Khazhismel Kumykov <khazhy@google.com> Cc: Guantao Liu <guantaol@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* epoll: pull all code between fetch_events and send_event into the loopSoheil Hassas Yeganeh2020-12-191-20/+21
| | | | | | | | | | | | | | This is a no-op change which simplifies the follow up patches. Link: https://lkml.kernel.org/r/20201106231635.3528496-7-soheil.kdev@gmail.com Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Khazhismel Kumykov <khazhy@google.com> Cc: Guantao Liu <guantaol@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* epoll: simplify and optimize busy loop logicSoheil Hassas Yeganeh2020-12-191-23/+17
| | | | | | | | | | | | | | | | | | | | | ep_events_available() is called multiple times around the busy loop logic, even though the logic is generally not used. ep_reset_busy_poll_napi_id() is similarly always called, even when busy loop is not used. Eliminate ep_reset_busy_poll_napi_id() and inline it inside ep_busy_loop(). Make ep_busy_loop() return whether there are any events available after the busy loop. This will eliminate unnecessary loads and branches, and simplifies the loop. Link: https://lkml.kernel.org/r/20201106231635.3528496-6-soheil.kdev@gmail.com Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Khazhismel Kumykov <khazhy@google.com> Cc: Guantao Liu <guantaol@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* epoll: move eavail next to the list_empty_careful checkSoheil Hassas Yeganeh2020-12-191-2/+1
| | | | | | | | | | | | | | This is a no-op change and simply to make the code more coherent. Link: https://lkml.kernel.org/r/20201106231635.3528496-5-soheil.kdev@gmail.com Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Khazhismel Kumykov <khazhy@google.com> Cc: Guantao Liu <guantaol@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* epoll: pull fatal signal checks into ep_send_events()Soheil Hassas Yeganeh2020-12-191-9/+8
| | | | | | | | | | | | | | | | | | | | | To simplify the code, pull in checking the fatal signals into ep_send_events(). ep_send_events() is called only from ep_poll(). Note that, previously, we were always checking fatal events, but it is checked only if eavail is true. This should be fine because the goal of that check is to quickly return from epoll_wait() when there is a pending fatal signal. Link: https://lkml.kernel.org/r/20201106231635.3528496-4-soheil.kdev@gmail.com Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Suggested-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Khazhismel Kumykov <khazhy@google.com> Cc: Guantao Liu <guantaol@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* epoll: simplify signal handlingSoheil Hassas Yeganeh2020-12-191-10/+10
| | | | | | | | | | | | | | | | | | Check signals before locking ep->lock, and immediately return -EINTR if there is any signal pending. This saves a few loads, stores, and branches from the hot path and simplifies the loop structure for follow up patches. Link: https://lkml.kernel.org/r/20201106231635.3528496-3-soheil.kdev@gmail.com Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Khazhismel Kumykov <khazhy@google.com> Cc: Guantao Liu <guantaol@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* epoll: check for events when removing a timed out thread from the wait queueSoheil Hassas Yeganeh2020-12-191-9/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "simplify ep_poll". This patch series is a followup based on the suggestions and feedback by Linus: https://lkml.kernel.org/r/CAHk-=wizk=OxUyQPbO8MS41w2Pag1kniUV5WdD5qWL-gq1kjDA@mail.gmail.com The first patch in the series is a fix for the epoll race in presence of timeouts, so that it can be cleanly backported to all affected stable kernels. The rest of the patch series simplify the ep_poll() implementation. Some of these simplifications result in minor performance enhancements as well. We have kept these changes under self tests and internal benchmarks for a few days, and there are minor (1-2%) performance enhancements as a result. This patch (of 8): After abc610e01c66 ("fs/epoll: avoid barrier after an epoll_wait(2) timeout"), we break out of the ep_poll loop upon timeout, without checking whether there is any new events available. Prior to that patch-series we always called ep_events_available() after exiting the loop. This can cause races and missed wakeups. For example, consider the following scenario reported by Guantao Liu: Suppose we have an eventfd added using EPOLLET to an epollfd. Thread 1: Sleeps for just below 5ms and then writes to an eventfd. Thread 2: Calls epoll_wait with a timeout of 5 ms. If it sees an event of the eventfd, it will write back on that fd. Thread 3: Calls epoll_wait with a negative timeout. Prior to abc610e01c66, it is guaranteed that Thread 3 will wake up either by Thread 1 or Thread 2. After abc610e01c66, Thread 3 can be blocked indefinitely if Thread 2 sees a timeout right before the write to the eventfd by Thread 1. Thread 2 will be woken up from schedule_hrtimeout_range and, with evail 0, it will not call ep_send_events(). To fix this issue: 1) Simplify the timed_out case as suggested by Linus. 2) while holding the lock, recheck whether the thread was woken up after its time out has reached. Note that (2) is different from Linus' original suggestion: It do not set "eavail = ep_events_available(ep)" to avoid unnecessary contention (when there are too many timed-out threads and a small number of events), as well as races mentioned in the discussion thread. This is the first patch in the series so that the backport to stable releases is straightforward. Link: https://lkml.kernel.org/r/20201106231635.3528496-1-soheil.kdev@gmail.com Link: https://lkml.kernel.org/r/CAHk-=wizk=OxUyQPbO8MS41w2Pag1kniUV5WdD5qWL-gq1kjDA@mail.gmail.com Link: https://lkml.kernel.org/r/20201106231635.3528496-2-soheil.kdev@gmail.com Fixes: abc610e01c66 ("fs/epoll: avoid barrier after an epoll_wait(2) timeout") Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Tested-by: Guantao Liu <guantaol@google.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Guantao Liu <guantaol@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Khazhismel Kumykov <khazhy@google.com> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'work.epoll' of ↵Linus Torvalds2020-12-161-415/+302
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull epoll updates from Al Viro: "Deal with epoll loop check/removal races sanely (among other things). The solution merged last cycle (pinning a bunch of struct file instances) had been forced by the wrong data structures; untangling that takes a bunch of preparations, but it's worth doing - control flow in there is ridiculously overcomplicated. Memory footprint has also gone down, while we are at it. This is not all I want to do in the area, but since I didn't get around to posting the followups they'll have to wait for the next cycle" * 'work.epoll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (27 commits) epoll: take epitem list out of struct file epoll: massage the check list insertion lift rcu_read_lock() into reverse_path_check() convert ->f_ep_links/->fllink to hlist ep_insert(): move creation of wakeup source past the fl_ep_links insertion fold ep_read_events_proc() into the only caller take the common part of ep_eventpoll_poll() and ep_item_poll() into helper ep_insert(): we only need tep->mtx around the insertion itself ep_insert(): don't open-code ep_remove() on failure exits lift locking/unlocking ep->mtx out of ep_{start,done}_scan() ep_send_events_proc(): fold into the caller lift the calls of ep_send_events_proc() into the callers lift the calls of ep_read_events_proc() into the callers ep_scan_ready_list(): prepare to splitup ep_loop_check_proc(): saner calling conventions get rid of ep_push_nested() ep_loop_check_proc(): lift pushing the cookie into callers clean reverse_path_check_proc() a bit reverse_path_check_proc(): don't bother with cookies reverse_path_check_proc(): sane arguments ...
| * epoll: take epitem list out of struct fileAl Viro2020-10-261-42/+126
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the head of epitem list out of struct file; for epoll ones it's moved into struct eventpoll (->refs there), for non-epoll - into the new object (struct epitem_head). In place of ->f_ep_links we leave a pointer to the list head (->f_ep). ->f_ep is protected by ->f_lock and it's zeroed as soon as the list of epitems becomes empty (that can happen only in ep_remove() by now). The list of files for reverse path check is *not* going through struct file now - it's a single-linked list going through epitem_head instances. It's terminated by ERR_PTR(-1) (== EP_UNACTIVE_POINTER), so the elements of list can be distinguished by head->next != NULL. epitem_head instances are allocated at ep_insert() time (by attach_epitem()) and freed either by ep_remove() (if it empties the set of epitems *and* epitem_head does not belong to the reverse path check list) or by clear_tfile_check_list() when the list is emptied (if the set of epitems is empty by that point). Allocations are done from a separate slab - minimal kmalloc() size is too large on some architectures. As the result, we trim struct file _and_ get rid of the games with temporary file references. Locking and barriers are interesting (aren't they always); see unlist_file() and ep_remove() for details. The non-obvious part is that ep_remove() needs to decide if it will be the one to free the damn thing *before* actually storing NULL to head->epitems.first - that's what smp_load_acquire is for in there. unlist_file() lockless path is safe, since we hit it only if we observe NULL in head->epitems.first and whoever had done that store is guaranteed to have observed non-NULL in head->next. IOW, their last access had been the store of NULL into ->epitems.first and we can safely free the sucker. OTOH, we are under rcu_read_lock() and both epitem and epitem->file have their freeing RCU-delayed. So if we see non-NULL ->epitems.first, we can grab ->f_lock (all epitems in there share the same struct file) and safely recheck the emptiness of ->epitems; again, ->next is still non-NULL, so ep_remove() couldn't have freed head yet. ->f_lock serializes us wrt ep_remove(); the rest is trivial. Note that once head->epitems becomes NULL, nothing can get inserted into it - the only remaining reference to head after that point is from the reverse path check list. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * epoll: massage the check list insertionAl Viro2020-10-261-4/+4
| | | | | | | | | | | | | | | | in the "non-epoll target" cases do it in ep_insert() rather than in do_epoll_ctl(), so that we do it only with some epitem is already guaranteed to exist. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * lift rcu_read_lock() into reverse_path_check()Al Viro2020-10-261-2/+2
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * convert ->f_ep_links/->fllink to hlistAl Viro2020-10-261-9/+9
| | | | | | | | | | | | we don't care about the order of elements there Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * ep_insert(): move creation of wakeup source past the fl_ep_links insertionAl Viro2020-10-261-11/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | That's the beginning of preparations for taking f_ep_links out of struct file. If insertion might fail, we will need a new failure exit. Having wakeup source creation done after that point will simplify life there; ep_remove() can (and commonly does) live with NULL epi->ws, so it can be used for cleanup after ep_create_wakeup_source() failure. It can't be used before the rbtree insertion, though, so if we are to unify all old failure exits, we need to move that thing down. Then we would be free to do simple kmem_cache_free() on the failure to insert into f_ep_links - no wakeup source to leak on that failure exit. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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