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* mm, vmalloc: use __GFP_HIGHMEM implicitlyMichal Hocko2017-05-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | __vmalloc* allows users to provide gfp flags for the underlying allocation. This API is quite popular $ git grep "=[[:space:]]__vmalloc\|return[[:space:]]*__vmalloc" | wc -l 77 The only problem is that many people are not aware that they really want to give __GFP_HIGHMEM along with other flags because there is really no reason to consume precious lowmemory on CONFIG_HIGHMEM systems for pages which are mapped to the kernel vmalloc space. About half of users don't use this flag, though. This signals that we make the API unnecessarily too complex. This patch simply uses __GFP_HIGHMEM implicitly when allocating pages to be mapped to the vmalloc space. Current users which add __GFP_HIGHMEM are simplified and drop the flag. Link: http://lkml.kernel.org/r/20170307141020.29107-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Cristopher Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-1/+1
| | | | | | | | | | | | | | | | | | | | <linux/sched/signal.h> We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/signal.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* fs/file: more unsigned file descriptorsAlexey Dobriyan2016-09-281-17/+17
| | | | | | | | | | | | | | | | | | | | | | | Propagate unsignedness for grand total of 149 bytes: $ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux add/remove: 0/0 grow/shrink: 0/10 up/down: 0/-149 (-149) function old new delta set_close_on_exec 99 98 -1 put_files_struct 201 200 -1 get_close_on_exec 59 58 -1 do_prlimit 498 497 -1 do_execveat_common.isra 1662 1661 -1 __close_fd 178 173 -5 do_dup2 219 204 -15 seq_show 685 660 -25 __alloc_fd 384 357 -27 dup_fd 718 646 -72 It mostly comes from converting "unsigned int" to "long" for bit operations. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* give readdir(2)/getdents(2)/etc. uniform exclusion with lseek()Al Viro2016-05-031-0/+5
| | | | | | same as read() on regular files has, and for the same reason. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* kmemcg: account certain kmem allocations to memcgVladimir Davydov2016-01-151-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mark those kmem allocations that are known to be easily triggered from userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to memcg. For the list, see below: - threadinfo - task_struct - task_delay_info - pid - cred - mm_struct - vm_area_struct and vm_region (nommu) - anon_vma and anon_vma_chain - signal_struct - sighand_struct - fs_struct - files_struct - fdtable and fdtable->full_fds_bits - dentry and external_name - inode for all filesystems. This is the most tedious part, because most filesystems overwrite the alloc_inode method. The list is far from complete, so feel free to add more objects. Nevertheless, it should be close to "account everything" approach and keep most workloads within bounds. Malevolent users will be able to breach the limit, but this was possible even with the former "account everything" approach (simply because it did not account everything in fact). [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tejun Heo <tj@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/file.c: __const_max is actually __const_min :-)Rasmus Villemoes2015-12-071-3/+3
| | | | | | | | | 7f4b36f9bb930 "get rid of files_defer_init()" inexplicably changed a min() to a __const_max() - but the __const_max macro actually gives the minimum... So no functional change, just less confusing naming. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: clear remainder of 'full_fds_bits' in dup_fd()Eric Biggers2015-11-061-32/+32
| | | | | | | | | This fixes a bug from commit f3f86e33dc3d ("vfs: Fix pathological performance case for __alloc_fd()"). v2: refactor to share fd bitmap copying code Signed-off-by: Eric Biggers <ebiggers3@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vfs: conditionally clear close-on-exec flagLinus Torvalds2015-11-011-1/+2
| | | | | | | | | | | | | | | We clear the close-on-exec flag when opening and closing files, and the bit was almost always already clear before. Avoid dirtying the cacheline if the clearning isn't necessary. That avoids unnecessary cacheline dirtying and bouncing in multi-socket environments. Eric Dumazet has a file descriptor benchmark that goes 4% faster from this on his two-socket machine. It's probably partly superlinear improvement due to getting slightly less spinlock contention on the file_lock spinlock due to less work in the critical section. Tested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vfs: Fix pathological performance case for __alloc_fd()Linus Torvalds2015-11-011-4/+35
| | | | | | | | | | | | | | | | | | | | | | | | | Al Viro points out that: > > * [Linux-specific aside] our __alloc_fd() can degrade quite badly > > with some use patterns. The cacheline pingpong in the bitmap is probably > > inevitable, unless we accept considerably heavier memory footprint, > > but we also have a case when alloc_fd() takes O(n) and it's _not_ hard > > to trigger - close(3);open(...); will have the next open() after that > > scanning the entire in-use bitmap. And Eric Dumazet has a somewhat realistic multithreaded microbenchmark that opens and closes a lot of sockets with minimal work per socket. This patch largely fixes it. We keep a 2nd-level bitmap of the open file bitmaps, showing which words are already full. So then we can traverse that second-level bitmap to efficiently skip already allocated file descriptors. On his benchmark, this improves performance by up to an order of magnitude, by avoiding the excessive open file bitmap scanning. Tested-and-acked-by: Eric Dumazet <edumazet@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/file.c: __fget() and dup2() atomicity rulesEric Dumazet2015-07-011-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __fget() does lockless fetch of pointer from the descriptor table, attempts to grab a reference and treats "it was already zero" as "it's already gone from the table, we just hadn't seen the store, let's fail". Unfortunately, that breaks the atomicity of dup2() - __fget() might see the old pointer, notice that it's been already dropped and treat that as "it's closed". What we should be getting is either the old file or new one, depending whether we come before or after dup2(). Dmitry had following test failing sometimes : int fd; void *Thread(void *x) { char buf; int n = read(fd, &buf, 1); if (n != 1) exit(printf("read failed: n=%d errno=%d\n", n, errno)); return 0; } int main() { fd = open("/dev/urandom", O_RDONLY); int fd2 = open("/dev/urandom", O_RDONLY); if (fd == -1 || fd2 == -1) exit(printf("open failed\n")); pthread_t th; pthread_create(&th, 0, Thread, 0); if (dup2(fd2, fd) == -1) exit(printf("dup2 failed\n")); pthread_join(th, 0); if (close(fd) == -1) exit(printf("close failed\n")); if (close(fd2) == -1) exit(printf("close failed\n")); printf("DONE\n"); return 0; } Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs/file.c: don't acquire files->file_lock in fd_install()Eric Dumazet2015-07-011-19/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mateusz Guzik reported : Currently obtaining a new file descriptor results in locking fdtable twice - once in order to reserve a slot and second time to fill it. Holding the spinlock in __fd_install() is needed in case a resize is done, or to prevent a resize. Mateusz provided an RFC patch and a micro benchmark : http://people.redhat.com/~mguzik/pipebench.c A resize is an unlikely operation in a process lifetime, as table size is at least doubled at every resize. We can use RCU instead of the spinlock. __fd_install() must wait if a resize is in progress. The resize must block new __fd_install() callers from starting, and wait that ongoing install are finished (synchronize_sched()) resize should be attempted by a single thread to not waste resources. rcu_sched variant is used, as __fd_install() and expand_fdtable() run from process context. It gives us a ~30% speedup using pipebench on a dual Intel(R) Xeon(R) CPU E5-2696 v2 @ 2.50GHz Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Mateusz Guzik <mguzik@redhat.com> Acked-by: Mateusz Guzik <mguzik@redhat.com> Tested-by: Mateusz Guzik <mguzik@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* mm: rcu-protected get_mm_exe_file()Konstantin Khlebnikov2015-04-171-2/+1
| | | | | | | | | | | | | | | This patch removes mm->mmap_sem from mm->exe_file read side. Also it kills dup_mm_exe_file() and moves exe_file duplication into dup_mmap() where both mmap_sems are locked. [akpm@linux-foundation.org: fix comment typo] Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/file.c: replace get_unused_fd() with get_unused_fd_flags(0)Yann Droneaud2014-12-111-1/+1
| | | | | | | | | | | | | | This patch replaces calls to get_unused_fd() with equivalent call to get_unused_fd_flags(0) to preserve current behavor for existing code. In a further patch, get_unused_fd() will be removed so that new code start using get_unused_fd_flags(), with the hope O_CLOEXEC could be used, either by default or choosen by userspace. Signed-off-by: Yann Droneaud <ydroneaud@opteya.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2014-10-131-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "The main changes in this cycle were: - changes related to No-CBs CPUs and NO_HZ_FULL - RCU-tasks implementation - torture-test updates - miscellaneous fixes - locktorture updates - RCU documentation updates" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (81 commits) workqueue: Use cond_resched_rcu_qs macro workqueue: Add quiescent state between work items locktorture: Cleanup header usage locktorture: Cannot hold read and write lock locktorture: Fix __acquire annotation for spinlock irq locktorture: Support rwlocks rcu: Eliminate deadlock between CPU hotplug and expedited grace periods locktorture: Document boot/module parameters rcutorture: Rename rcutorture_runnable parameter locktorture: Add test scenario for rwsem_lock locktorture: Add test scenario for mutex_lock locktorture: Make torture scripting account for new _runnable name locktorture: Introduce torture context locktorture: Support rwsems locktorture: Add infrastructure for torturing read locks torture: Address race in module cleanup locktorture: Make statistics generic locktorture: Teach about lock debugging locktorture: Support mutexes locktorture: Add documentation ...
| * rcu: Provide cond_resched_rcu_qs() to force quiescent states in long loopsPaul E. McKenney2014-09-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | RCU-tasks requires the occasional voluntary context switch from CPU-bound in-kernel tasks. In some cases, this requires instrumenting cond_resched(). However, there is some reluctance to countenance unconditionally instrumenting cond_resched() (see http://lwn.net/Articles/603252/), so this commit creates a separate cond_resched_rcu_qs() that may be used in place of cond_resched() in locations prone to long-duration in-kernel looping. This commit currently instruments only RCU-tasks. Future possibilities include also instrumenting RCU, RCU-bh, and RCU-sched in order to reduce IPI usage. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* | missing annotation in fs/file.cAl Viro2014-10-091-0/+1
|/ | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs/file.c: don't open-code kvfree()Al Viro2014-05-061-8/+3
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2014-04-121-7/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: "The first vfs pile, with deep apologies for being very late in this window. Assorted cleanups and fixes, plus a large preparatory part of iov_iter work. There's a lot more of that, but it'll probably go into the next merge window - it *does* shape up nicely, removes a lot of boilerplate, gets rid of locking inconsistencie between aio_write and splice_write and I hope to get Kent's direct-io rewrite merged into the same queue, but some of the stuff after this point is having (mostly trivial) conflicts with the things already merged into mainline and with some I want more testing. This one passes LTP and xfstests without regressions, in addition to usual beating. BTW, readahead02 in ltp syscalls testsuite has started giving failures since "mm/readahead.c: fix readahead failure for memoryless NUMA nodes and limit readahead pages" - might be a false positive, might be a real regression..." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) missing bits of "splice: fix racy pipe->buffers uses" cifs: fix the race in cifs_writev() ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure kill generic_file_buffered_write() ocfs2_file_aio_write(): switch to generic_perform_write() ceph_aio_write(): switch to generic_perform_write() xfs_file_buffered_aio_write(): switch to generic_perform_write() export generic_perform_write(), start getting rid of generic_file_buffer_write() generic_file_direct_write(): get rid of ppos argument btrfs_file_aio_write(): get rid of ppos kill the 5th argument of generic_file_buffered_write() kill the 4th argument of __generic_file_aio_write() lustre: don't open-code kernel_recvmsg() ocfs2: don't open-code kernel_recvmsg() drbd: don't open-code kernel_recvmsg() constify blk_rq_map_user_iov() and friends lustre: switch to kernel_sendmsg() ocfs2: don't open-code kernel_sendmsg() take iov_iter stuff to mm/iov_iter.c process_vm_access: tidy up a bit ...
| * get rid of files_defer_init()Al Viro2014-04-021-7/+4
| | | | | | | | | | | | | | | | the only thing it's doing these days is calculation of upper limit for fs.nr_open sysctl and that can be done statically Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds2014-03-311-1/+1
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "Main changes: - Torture-test changes, including refactoring of rcutorture and introduction of a vestigial locktorture. - Real-time latency fixes. - Documentation updates. - Miscellaneous fixes" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits) rcu: Provide grace-period piggybacking API rcu: Ensure kernel/rcu/rcu.h can be sourced/used stand-alone rcu: Fix sparse warning for rcu_expedited from kernel/ksysfs.c notifier: Substitute rcu_access_pointer() for rcu_dereference_raw() Documentation/memory-barriers.txt: Clarify release/acquire ordering rcutorture: Save kvm.sh output to log rcutorture: Add a lock_busted to test the test rcutorture: Place kvm-test-1-run.sh output into res directory rcutorture: Rename TREE_RCU-Kconfig.txt locktorture: Add kvm-recheck.sh plug-in for locktorture rcutorture: Gracefully handle NULL cleanup hooks locktorture: Add vestigial locktorture configuration rcutorture: Introduce "rcu" directory level underneath configs rcutorture: Rename kvm-test-1-rcu.sh rcutorture: Remove RCU dependencies from ver_functions.sh API rcutorture: Create CFcommon file for common Kconfig parameters rcutorture: Create config files for scripted test-the-test testing rcutorture: Add an rcu_busted to test the test locktorture: Add a lock-torture kernel module rcutorture: Abstract kvm-recheck.sh ...
| * fs: Substitute rcu_access_pointer() for rcu_dereference_raw()Paul E. McKenney2014-02-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | (Trivial patch.) If the code is looking at the RCU-protected pointer itself, but not dereferencing it, the rcu_dereference() functions can be downgraded to rcu_access_pointer(). This commit makes this downgrade in __alloc_fd(), which simply compares the RCU-protected pointer against NULL with no dereferencing. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Josh Triplett <josh@joshtriplett.org>
* | vfs: Don't let __fdget_pos() get FMODE_PATH filesEric Biggers2014-03-231-15/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit bd2a31d522344 ("get rid of fget_light()") introduced the __fdget_pos() function, which returns the resulting file pointer and fdput flags combined in an 'unsigned long'. However, it also changed the behavior to return files with FMODE_PATH set, which shouldn't happen because read(), write(), lseek(), etc. aren't allowed on such files. This commit restores the old behavior. This regression actually had no effect on read() and write() since FMODE_READ and FMODE_WRITE are not set on file descriptors opened with O_PATH, but it did cause lseek() on a file descriptor opened with O_PATH to fail with ESPIPE rather than EBADF. Signed-off-by: Eric Biggers <ebiggers3@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | get rid of fget_light()Al Viro2014-03-101-13/+43
|/ | | | | | | | instead of returning the flags by reference, we can just have the low-level primitive return those in lower bits of unsigned long, with struct file * derived from the rest. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs/file.c:fdtable: avoid triggering OOMs from alloc_fdmemEric W. Biederman2014-02-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Recently due to a spike in connections per second memcached on 3 separate boxes triggered the OOM killer from accept. At the time the OOM killer was triggered there was 4GB out of 36GB free in zone 1. The problem was that alloc_fdtable was allocating an order 3 page (32KiB) to hold a bitmap, and there was sufficient fragmentation that the largest page available was 8KiB. I find the logic that PAGE_ALLOC_COSTLY_ORDER can't fail pretty dubious but I do agree that order 3 allocations are very likely to succeed. There are always pathologies where order > 0 allocations can fail when there are copious amounts of free memory available. Using the pigeon hole principle it is easy to show that it requires 1 page more than 50% of the pages being free to guarantee an order 1 (8KiB) allocation will succeed, 1 page more than 75% of the pages being free to guarantee an order 2 (16KiB) allocation will succeed and 1 page more than 87.5% of the pages being free to guarantee an order 3 allocate will succeed. A server churning memory with a lot of small requests and replies like memcached is a common case that if anything can will skew the odds against large pages being available. Therefore let's not give external applications a practical way to kill linux server applications, and specify __GFP_NORETRY to the kmalloc in alloc_fdmem. Unless I am misreading the code and by the time the code reaches should_alloc_retry in __alloc_pages_slowpath (where __GFP_NORETRY becomes signification). We have already tried everything reasonable to allocate a page and the only thing left to do is wait. So not waiting and falling back to vmalloc immediately seems like the reasonable thing to do even if there wasn't a chance of triggering the OOM killer. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Cong Wang <cwang@twopensource.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: __fget_light() can use __fget() in slow pathOleg Nesterov2014-01-251-11/+3
| | | | | | | | The slow path in __fget_light() can use __fget() to avoid the code duplication. Saves 232 bytes. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: factor out common code in fget_light() and fget_raw_light()Oleg Nesterov2014-01-251-24/+9
| | | | | | | | | Apart from FMODE_PATH check fget_light() and fget_raw_light() are identical, shift the code into the new helper, __fget_light(fd, mask). Saves 208 bytes. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: factor out common code in fget() and fget_raw()Oleg Nesterov2014-01-251-17/+8
| | | | | | | | | Apart from FMODE_PATH check fget() and fget_raw() are identical, shift the code into the new simple helper, __fget(fd, mask). Saves 160 bytes. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* change close_files() to use rcu_dereference_raw(files->fdt)Oleg Nesterov2014-01-251-17/+9
| | | | | | | | | | | | | | | | | | | | | put_files_struct() and close_files() do rcu_read_lock() to make rcu_dereference_check_fdtable() happy. This looks a bit ugly, files_fdtable() just reads the pointer, we can simply use rcu_dereference_raw() to avoid the warning. The patch also changes close_files() to return fdt, this avoids another rcu_read_lock()/files_fdtable() in put_files_struct(). I think close_files() needs more cleanups: - we do not need xchg() exactly because we are the last user of this files_struct - "if (file)" should be turned into WARN_ON(!file) Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* introduce __fcheck_files() to fix rcu_dereference_check_fdtable(), kill ↵Oleg Nesterov2014-01-251-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | rcu_my_thread_group_empty() rcu_dereference_check_fdtable() looks very wrong, 1. rcu_my_thread_group_empty() was added by 844b9a8707f1 "vfs: fix RCU-lockdep false positive due to /proc" but it doesn't really fix the problem. A CLONE_THREAD (without CLONE_FILES) task can hit the same race with get_files_struct(). And otoh rcu_my_thread_group_empty() can suppress the correct warning if the caller is the CLONE_FILES (without CLONE_THREAD) task. 2. files->count == 1 check is not really right too. Even if this files_struct is not shared it is not safe to access it lockless unless the caller is the owner. Otoh, this check is sub-optimal. files->count == 0 always means it is safe to use it lockless even if files != current->files, but put_files_struct() has to take rcu_read_lock(). See the next patch. This patch removes the buggy checks and turns fcheck_files() into __fcheck_files() which uses rcu_dereference_raw(), the "unshared" callers, fget_light() and fget_raw_light(), can use it to avoid the warning from RCU-lockdep. fcheck_files() is trivially reimplemented as rcu_lockdep_assert() plus __fcheck_files(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* don't bother with deferred freeing of fdtablesAl Viro2013-05-011-66/+2
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* locking: Various static lock initializer fixesThomas Gleixner2013-02-191-1/+1
| | | | | | | | | The static lock initializers want to be fed the proper name of the lock and not some random string. In mainline random strings are obfuscating the readability of debug output, but for RT they prevent the spinlock substitution. Fix it up. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* misc: remove __dev* attributes.Greg Kroah-Hartman2013-01-041-1/+1
| | | | | | | | | | | | | | CONFIG_HOTPLUG is going away as an option. As a result, the __dev* markings need to be removed. This change removes the last of the __dev* markings from the kernel from a variety of different, tiny, places. Based on patches originally written by Bill Pemberton, but redone by me in order to handle some of the coding style issues better, by hand. Cc: Bill Pemberton <wfp5p@virginia.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2012-12-121-6/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal Pull big execve/kernel_thread/fork unification series from Al Viro: "All architectures are converted to new model. Quite a bit of that stuff is actually shared with architecture trees; in such cases it's literally shared branch pulled by both, not a cherry-pick. A lot of ugliness and black magic is gone (-3KLoC total in this one): - kernel_thread()/kernel_execve()/sys_execve() redesign. We don't do syscalls from kernel anymore for either kernel_thread() or kernel_execve(): kernel_thread() is essentially clone(2) with callback run before we return to userland, the callbacks either never return or do successful do_execve() before returning. kernel_execve() is a wrapper for do_execve() - it doesn't need to do transition to user mode anymore. As a result kernel_thread() and kernel_execve() are arch-independent now - they live in kernel/fork.c and fs/exec.c resp. sys_execve() is also in fs/exec.c and it's completely architecture-independent. - daemonize() is gone, along with its parts in fs/*.c - struct pt_regs * is no longer passed to do_fork/copy_process/ copy_thread/do_execve/search_binary_handler/->load_binary/do_coredump. - sys_fork()/sys_vfork()/sys_clone() unified; some architectures still need wrappers (ones with callee-saved registers not saved in pt_regs on syscall entry), but the main part of those suckers is in kernel/fork.c now." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: (113 commits) do_coredump(): get rid of pt_regs argument print_fatal_signal(): get rid of pt_regs argument ptrace_signal(): get rid of unused arguments get rid of ptrace_signal_deliver() arguments new helper: signal_pt_regs() unify default ptrace_signal_deliver flagday: kill pt_regs argument of do_fork() death to idle_regs() don't pass regs to copy_process() flagday: don't pass regs to copy_thread() bfin: switch to generic vfork, get rid of pointless wrappers xtensa: switch to generic clone() openrisc: switch to use of generic fork and clone unicore32: switch to generic clone(2) score: switch to generic fork/vfork/clone c6x: sanitize copy_thread(), get rid of clone(2) wrapper, switch to generic clone() take sys_fork/sys_vfork/sys_clone prototypes to linux/syscalls.h mn10300: switch to generic fork/vfork/clone h8300: switch to generic fork/vfork/clone tile: switch to generic clone() ... Conflicts: arch/microblaze/include/asm/Kbuild
| * kill daemonize()Al Viro2012-11-291-6/+0
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | fix off-by-one in argument passed by iterate_fd() to callbacksAl Viro2012-11-301-6/+8
|/ | | | | | | | Noticed by Pavel Roskin; the thing in his patch I disagree with was compensating for that shite in callbacks instead of fixing it once in the iterator itself. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2012-11-181-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc VFS fixes from Al Viro: "Remove a bogus BUG_ON() that can trigger spuriously + alpha bits of do_mount() constification I'd missed during the merge window." This pull request came in a week ago, I missed it for some reason. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: kill bogus BUG_ON() in do_close_on_exec() missing const in alpha callers of do_mount()
| * kill bogus BUG_ON() in do_close_on_exec()Al Viro2012-11-121-1/+0
| | | | | | | | | | | | | | | | | | It can be legitimately triggered via procfs access. Now, at least 2 of 3 of get_files_struct() callers in procfs are useless, but when and if we get rid of those we can always add WARN_ON() here. BUG_ON() at that spot is simply wrong. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Return the right error value when dup[23]() newfd argument is too largeAl Viro2012-10-311-2/+2
|/ | | | | | | | | | | | | | | | | Jack Lin reports that the error return from dup3() for the RLIMIT_NOFILE case changed incorrectly after 3.6. The culprit is commit f33ff9927f42 ("take rlimit check to callers of expand_files()") which when it moved the "return -EMFILE" out to the caller, didn't notice that the dup3() had special code to turn the EMFILE return into EBADF. The replace_fd() helper that got added later then inherited the bug too. Reported-by: Jack Lin <linliangjie@huawei.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> [ Noted more bugs, wrote proper changelog, fixed up typos - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dup3: Return an error when oldfd == newfd.Richard W.M. Jones2012-10-101-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I have tested the attached patch to fix the dup3 regression. Rich. From 0944e30e12dec6544b3602626b60ff412375c78f Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" <rjones@redhat.com> Date: Tue, 9 Oct 2012 14:42:45 +0100 Subject: [PATCH] dup3: Return an error when oldfd == newfd. The following commit: commit fe17f22d7fd0e344ef6447238f799bb49f670c6f Author: Al Viro <viro@zeniv.linux.org.uk> Date: Tue Aug 21 11:48:11 2012 -0400 take purely descriptor-related stuff from fcntl.c to file.c was supposed to be just code motion, but it dropped the following two lines: if (unlikely(oldfd == newfd)) return -EINVAL; from the dup3 system call. dup3 is not specified by POSIX, so Linux can do what it likes. However the POSIX proposal for dup3 [1] states that it should return an error if oldfd == newfd. [1] http://austingroupbugs.net/view.php?id=411 Signed-off-by: Richard W.M. Jones <rjones@redhat.com> Tested-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* export fget_lightAl Viro2012-09-271-0/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helper: daemonize_descriptors()Al Viro2012-09-271-0/+6
| | | | | | | | descriptor-related parts of daemonize, done right. As the result we simplify the locking rules for ->files - we hold task_lock in *all* cases when we modify ->files. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helper: iterate_fd()Al Viro2012-09-271-0/+21
| | | | | | | | | | | | | iterates through the opened files in given descriptor table, calling a supplied function; we stop once non-zero is returned. Callback gets struct file *, descriptor number and const void * argument passed to iterator. It is called with files->file_lock held, so it is not allowed to block. tty_io, netprio_cgroup and selinux flush_unauthorized_files() converted to its use. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* make expand_files() and alloc_fd() staticAl Viro2012-09-271-2/+2
| | | | | | no callers outside of fs/file.c left Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* take __{set,clear}_{open_fd,close_on_exec}() into fs/file.cAl Viro2012-09-271-0/+20
| | | | | | nobody uses those outside anymore. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helper: replace_fd()Al Viro2012-09-271-29/+62
| | | | | | analog of dup2(), except that it takes struct file * as source. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* take purely descriptor-related stuff from fcntl.c to file.cAl Viro2012-09-271-0/+132
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* take close-on-exec logics to fs/file.c, clean it up a bitAl Viro2012-09-271-0/+37
| | | | | | | ... and add cond_resched() there, while we are at it. We can get large latencies as is... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* take descriptor-related part of close() to file.cAl Viro2012-09-271-0/+26
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* take fget() and friends to fs/file.cAl Viro2012-09-271-0/+106
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* expose a low-level variant of fd_install() for binderAl Viro2012-09-271-2/+14
| | | | | | | | | | | | | | Similar situation to that of __alloc_fd(); do not use unless you really have to. You should not touch any descriptor table other than your own; it's a sure sign of a really bad API design. As with __alloc_fd(), you *must* use a first-class reference to struct files_struct; something obtained by get_files_struct(some task) (let alone direct task->files) will not do. It must be either current->files, or obtained by get_files_struct(current) by the owner of that sucker and given to you. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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