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* vfs: move ACL cache lookup into generic codeLinus Torvalds2011-07-251-3/+49
| | | | | | | | | | | | | | This moves logic for checking the cached ACL values from low-level filesystems into generic code. The end result is a streamlined ACL check that doesn't need to load the inode->i_op->check_acl pointer at all for the common cached case. The filesystems also don't need to check for a non-blocking RCU walk case in their acl_check() functions, because that is all handled at a VFS layer. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* VFS: Fixup kerneldoc for generic_permission()Tobias Klauser2011-07-211-1/+0
| | | | | | | | The flags parameter went away in d749519b444db985e40b897f73ce1898b11f997e Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* unexport kern_path_parent()Al Viro2011-07-201-1/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* switch vfs_path_lookup() to struct pathAl Viro2011-07-201-5/+11
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* kill lookup_create()Al Viro2011-07-201-36/+18
| | | | | | folded into the only caller (kern_path_create()) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* new helpers: kern_path_create/user_path_createAl Viro2011-07-201-78/+76
| | | | | | | combination of kern_path_parent() and lookup_create(). Does *not* expose struct nameidata to caller. Syscalls converted to that... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* kill LOOKUP_CONTINUEAl Viro2011-07-201-8/+3
| | | | | | LOOKUP_PARENT is equivalent to it now Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* don't transliterate lower bits of ->intent.open.flags to FMODE_...Al Viro2011-07-201-19/+2
| | | | | | ->create() instances are much happier that way... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Don't pass nameidata when calling vfs_create() from mknod()Al Viro2011-07-201-1/+1
| | | | | | | All instances can cope with that now (and ceph one actually starts working properly). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* merge do_revalidate() into its only callerAl Viro2011-07-201-24/+18
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* no reason to keep exec_permission() separate nowAl Viro2011-07-201-41/+4
| | | | | | cache footprint alone makes it a bad idea... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* massage generic_permission() to treat directories on a separate pathAl Viro2011-07-201-4/+13
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* ->permission() sanitizing: don't pass flags to exec_permission()Al Viro2011-07-201-10/+7
| | | | | | | pass mask instead; kill security_inode_exec_permission() since we can use security_inode_permission() instead. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* ->permission() sanitizing: don't pass flags to ->permission()Al Viro2011-07-201-2/+2
| | | | | | not used by the instances anymore. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* ->permission() sanitizing: don't pass flags to generic_permission()Al Viro2011-07-201-2/+2
| | | | | | | redundant; all callers get it duplicated in mask & MAY_NOT_BLOCK and none of them removes that bit. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* ->permission() sanitizing: don't pass flags to ->check_acl()Al Viro2011-07-201-5/+5
| | | | | | not used in the instances anymore. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* ->permission() sanitizing: pass MAY_NOT_BLOCK to ->check_acl()Al Viro2011-07-201-2/+2
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* ->permission() sanitizing: MAY_NOT_BLOCKAl Viro2011-07-201-2/+5
| | | | | | Duplicate the flags argument into mask bitmap. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* kill check_acl callback of generic_permission()Al Viro2011-07-201-10/+7
| | | | | | | its value depends only on inode and does not change; we might as well store it in ->i_op->check_acl and be done with that. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* lockless get_write_access/deny_write_accessAl Viro2011-07-201-46/+0
| | | | | | new helpers: atomic_inc_unless_negative()/atomic_dec_unless_positive() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* move exec_permission() up to the rest of permission-related functionsAl Viro2011-07-201-34/+38
| | | | | | ... and convert the comment before it into linuxdoc form. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* kill file_permission() completelyAl Viro2011-07-201-18/+0
| | | | | | convert the last remaining caller to inode_permission() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* switch path_init() to exec_permission()Al Viro2011-07-201-1/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* make exec_permission(dir) really equivalent to inode_permission(dir, MAY_EXEC)Al Viro2011-07-201-9/+9
| | | | | | | | | | | | | capability overrides apply only to the default case; if fs has ->permission() that does _not_ call generic_permission(), we have no business doing them. Moreover, if it has ->permission() that does call generic_permission(), we have no need to recheck capabilities. Besides, the capability overrides should apply only if we got EACCES from acl_permission_check(); any other value (-EIO, etc.) should be returned to caller, capabilities or not capabilities. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: add a DCACHE_NEED_LOOKUP flag for d_flagsJosef Bacik2011-07-201-0/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | Btrfs (and I'd venture most other fs's) stores its indexes in nice disk order for readdir, but unfortunately in the case of anything that stats the files in order that readdir spits back (like oh say ls) that means we still have to do the normal lookup of the file, which means looking up our other index and then looking up the inode. What I want is a way to create dummy dentries when we find them in readdir so that when ls or anything else subsequently does a stat(), we already have the location information in the dentry and can go straight to the inode itself. The lookup stuff just assumes that if it finds a dentry it is done, it doesn't perform a lookup. So add a DCACHE_NEED_LOOKUP flag so that the lookup code knows it still needs to run i_op->lookup() on the parent to get the inode for the dentry. I have tested this with btrfs and I went from something that looks like this http://people.redhat.com/jwhiter/ls-noreada.png To this http://people.redhat.com/jwhiter/ls-good.png Thats a savings of 1300 seconds, or 22 minutes. That is a significant savings. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: fix race in rcu lookup of pruned dentryLinus Torvalds2011-07-201-1/+6
| | | | | | | | | | Don't update *inode in __follow_mount_rcu() until we'd verified that there is mountpoint there. Kudos to Hugh Dickins for catching that one in the first place and eventually figuring out the solution (and catching a braino in the earlier version of patch). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Fix ->d_lock locking order in unlazy_walk()Al Viro2011-07-131-0/+2
| | | | | | | | Make sure that child is still a child of parent before nested locking of child->d_lock in unlazy_walk(); otherwise we are risking a violation of locking order and deadlocks. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fix comment in generic_permission()Al Viro2011-06-201-1/+2
| | | | | | | CAP_DAC_OVERRIDE is enough for MAY_EXEC on directory, even if no exec bits are set. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* kill obsolete comment for follow_down()Al Viro2011-06-201-3/+0
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* VFS: Fix vfsmount overput on simultaneous automountAl Viro2011-06-161-8/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [Kudos to dhowells for tracking that crap down] If two processes attempt to cause automounting on the same mountpoint at the same time, the vfsmount holding the mountpoint will be left with one too few references on it, causing a BUG when the kernel tries to clean up. The problem is that lock_mount() drops the caller's reference to the mountpoint's vfsmount in the case where it finds something already mounted on the mountpoint as it transits to the mounted filesystem and replaces path->mnt with the new mountpoint vfsmount. During a pathwalk, however, we don't take a reference on the vfsmount if it is the same as the one in the nameidata struct, but do_add_mount() doesn't know this. The fix is to make sure we have a ref on the vfsmount of the mountpoint before calling do_add_mount(). However, if lock_mount() doesn't transit, we're then left with an extra ref on the mountpoint vfsmount which needs releasing. We can handle that in follow_managed() by not making assumptions about what we can and what we cannot get from lookup_mnt() as the current code does. The callers of follow_managed() expect that reference to path->mnt will be grabbed iff path->mnt has been changed. follow_managed() and follow_automount() keep track of whether such reference has been grabbed and assume that it'll happen in those and only those cases that'll have us return with changed path->mnt. That assumption is almost correct - it breaks in case of racing automounts and in even harder to hit race between following a mountpoint and a couple of mount --move. The thing is, we don't need to make that assumption at all - after the end of loop in follow_manage() we can check if path->mnt has ended up unchanged and do mntput() if needed. The BUG can be reproduced with the following test program: #include <stdio.h> #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include <sys/wait.h> int main(int argc, char **argv) { int pid, ws; struct stat buf; pid = fork(); stat(argv[1], &buf); if (pid > 0) wait(&ws); return 0; } and the following procedure: (1) Mount an NFS volume that on the server has something else mounted on a subdirectory. For instance, I can mount / from my server: mount warthog:/ /mnt -t nfs4 -r On the server /data has another filesystem mounted on it, so NFS will see a change in FSID as it walks down the path, and will mark /mnt/data as being a mountpoint. This will cause the automount code to be triggered. !!! Do not look inside the mounted fs at this point !!! (2) Run the above program on a file within the submount to generate two simultaneous automount requests: /tmp/forkstat /mnt/data/testfile (3) Unmount the automounted submount: umount /mnt/data (4) Unmount the original mount: umount /mnt At this point the kernel should throw a BUG with something like the following: BUG: Dentry ffff880032e3c5c0{i=2,n=} still in use (1) [unmount of nfs4 0:12] Note that the bug appears on the root dentry of the original mount, not the mountpoint and not the submount because sys_umount() hasn't got to its final mntput_no_expire() yet, but this isn't so obvious from the call trace: [<ffffffff8117cd82>] shrink_dcache_for_umount+0x69/0x82 [<ffffffff8116160e>] generic_shutdown_super+0x37/0x15b [<ffffffffa00fae56>] ? nfs_super_return_all_delegations+0x2e/0x1b1 [nfs] [<ffffffff811617f3>] kill_anon_super+0x1d/0x7e [<ffffffffa00d0be1>] nfs4_kill_super+0x60/0xb6 [nfs] [<ffffffff81161c17>] deactivate_locked_super+0x34/0x83 [<ffffffff811629ff>] deactivate_super+0x6f/0x7b [<ffffffff81186261>] mntput_no_expire+0x18d/0x199 [<ffffffff811862a8>] mntput+0x3b/0x44 [<ffffffff81186d87>] release_mounts+0xa2/0xbf [<ffffffff811876af>] sys_umount+0x47a/0x4ba [<ffffffff8109e1ca>] ? trace_hardirqs_on_caller+0x1fd/0x22f [<ffffffff816ea86b>] system_call_fastpath+0x16/0x1b as do_umount() is inlined. However, you can see release_mounts() in there. Note also that it may be necessary to have multiple CPU cores to be able to trigger this bug. Tested-by: Jeff Layton <jlayton@redhat.com> Tested-by: Ian Kent <raven@themaw.net> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fix wrong iput on d_inode introduced by e6bc45d65dTörök Edwin2011-06-161-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Git bisection shows that commit e6bc45d65df8599fdbae73be9cec4ceed274db53 causes BUG_ONs under high I/O load: kernel BUG at fs/inode.c:1368! [ 2862.501007] Call Trace: [ 2862.501007] [<ffffffff811691d8>] d_kill+0xf8/0x140 [ 2862.501007] [<ffffffff81169c19>] dput+0xc9/0x190 [ 2862.501007] [<ffffffff8115577f>] fput+0x15f/0x210 [ 2862.501007] [<ffffffff81152171>] filp_close+0x61/0x90 [ 2862.501007] [<ffffffff81152251>] sys_close+0xb1/0x110 [ 2862.501007] [<ffffffff814c14fb>] system_call_fastpath+0x16/0x1b A reliable way to reproduce this bug is: Login to KDE, run 'rsnapshot sync', and apt-get install openjdk-6-jdk, and apt-get remove openjdk-6-jdk. The buggy part of the patch is this: struct inode *inode = NULL; ..... - if (nd.last.name[nd.last.len]) - goto slashes; inode = dentry->d_inode; - if (inode) - ihold(inode); + if (nd.last.name[nd.last.len] || !inode) + goto slashes; + ihold(inode) ... if (inode) iput(inode); /* truncate the inode here */ If nd.last.name[nd.last.len] is nonzero (and thus goto slashes branch is taken), and dentry->d_inode is non-NULL, then this code now does an additional iput on the inode, which is wrong. Fix this by only setting the inode variable if nd.last.name[nd.last.len] is 0. Reference: https://lkml.org/lkml/2011/6/15/50 Reported-by: Norbert Preining <preining@logic.at> Reported-by: Török Edwin <edwintorok@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Török Edwin <edwintorok@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: make unlink() and rmdir() return ENOENT in preference to EROFSTheodore Ts'o2011-06-071-4/+7
| | | | | | | | | | | If user space attempts to remove a non-existent file or directory, and the file system is mounted read-only, return ENOENT instead of EROFS. Either error code is arguably valid/correct, but ENOENT is a more specific error message. Reported-by: Michael Tokarev <mjt@tls.msk.ru> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: shrink_dcache_parent before rmdir, dir renameSage Weil2011-05-301-0/+3
| | | | | | | | | | The dentry_unhash push-down series missed that shink_dcache_parent needs to be called prior to rmdir or dir rename to clear DCACHE_REFERENCED and allow efficient dentry reclaim. Reported-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Lift the check for automount points into do_lookup()Al Viro2011-05-271-5/+5
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Trim excessive arguments of follow_mount_rcu()Al Viro2011-05-271-18/+8
| | | | | | | | | | ... and kill a useless local variable in follow_dotdot_rcu(), while we are at it - follow_mount_rcu(nd, path, inode) *always* assigned value to *inode, and always it had been path->dentry->d_inode (aka nd->path.dentry->d_inode, since it always got &nd->path as the second argument). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* split __follow_mount_rcu() into normal and .. casesAl Viro2011-05-271-9/+26
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2011-05-261-242/+138
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (25 commits) cifs: remove unnecessary dentry_unhash on rmdir/rename_dir ocfs2: remove unnecessary dentry_unhash on rmdir/rename_dir exofs: remove unnecessary dentry_unhash on rmdir/rename_dir nfs: remove unnecessary dentry_unhash on rmdir/rename_dir ext2: remove unnecessary dentry_unhash on rmdir/rename_dir ext3: remove unnecessary dentry_unhash on rmdir/rename_dir ext4: remove unnecessary dentry_unhash on rmdir/rename_dir btrfs: remove unnecessary dentry_unhash in rmdir/rename_dir ceph: remove unnecessary dentry_unhash calls vfs: clean up vfs_rename_other vfs: clean up vfs_rename_dir vfs: clean up vfs_rmdir vfs: fix vfs_rename_dir for FS_RENAME_DOES_D_MOVE filesystems libfs: drop unneeded dentry_unhash vfs: update dentry_unhash() comment vfs: push dentry_unhash on rename_dir into file systems vfs: push dentry_unhash on rmdir into file systems vfs: remove dget() from dentry_unhash() vfs: dentry_unhash immediately prior to rmdir vfs: Block mmapped writes while the fs is frozen ...
| * vfs: clean up vfs_rename_otherSage Weil2011-05-261-11/+14
| | | | | | | | | | | | | | Simplify control flow to match vfs_rename_dir. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: clean up vfs_rename_dirSage Weil2011-05-261-11/+15
| | | | | | | | | | | | | | Simplify control flow through vfs_rename_dir. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: clean up vfs_rmdirSage Weil2011-05-261-14/+17
| | | | | | | | | | | | | | Simplify the control flow with an out label. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: fix vfs_rename_dir for FS_RENAME_DOES_D_MOVE filesystemsMiklos Szeredi2011-05-261-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | vfs_rename_dir() doesn't properly account for filesystems with FS_RENAME_DOES_D_MOVE. If new_dentry has a target inode attached, it unhashes the new_dentry prior to the rename() iop and rehashes it after, but doesn't account for the possibility that rename() may have swapped {old,new}_dentry. For FS_RENAME_DOES_D_MOVE filesystems, it rehashes new_dentry (now the old renamed-from name, which d_move() expected to go away), such that a subsequent lookup will find it. Currently all FS_RENAME_DOES_D_MOVE filesystems compensate for this by failing in d_revalidate. The bug was introduced by: commit 349457ccf2592c14bdf13b6706170ae2e94931b1 "[PATCH] Allow file systems to manually d_move() inside of ->rename()" Fix by not rehashing the new dentry. Rehashing used to be needed by d_move() but isn't anymore. Reported-by: Sage Weil <sage@newdream.net> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: update dentry_unhash() commentSage Weil2011-05-261-4/+4
| | | | | | | | | | | | | | The helper is now only called by file systems, not the VFS. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: push dentry_unhash on rename_dir into file systemsSage Weil2011-05-261-10/+2
| | | | | | | | | | | | | | | | | | | | Only a few file systems need this. Start by pushing it down into each rename method (except gfs2 and xfs) so that it can be dealt with on a per-fs basis. Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: push dentry_unhash on rmdir into file systemsSage Weil2011-05-261-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | Only a few file systems need this. Start by pushing it down into each fs rmdir method (except gfs2 and xfs) so it can be dealt with on a per-fs basis. This does not change behavior for any in-tree file systems. Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: remove dget() from dentry_unhash()Sage Weil2011-05-261-4/+1
| | | | | | | | | | | | | | | | | | | | | | This serves no useful purpose that I can discern. All callers (rename, rmdir) hold their own reference to the dentry. A quick audit of all file systems showed no relevant checks on the value of d_count in vfs_rmdir/vfs_rename_dir paths. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: dentry_unhash immediately prior to rmdirSage Weil2011-05-261-2/+2
| | | | | | | | | | | | | | | | | | This presumes that there is no reason to unhash a dentry if we fail because it is a mountpoint or the LSM check fails, and that the LSM checks do not depend on the dentry being unhashed. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * merge handle_reval_dot and nameidata_drop_rcu_lastAl Viro2011-05-261-81/+40
| | | | | | | | | | | | | | | | | | | | | | new helper: complete_walk(). Done on successful completion of walk, drops out of RCU mode, does d_revalidate of final result if that hadn't been done already. handle_reval_dot() and nameidata_drop_rcu_last() subsumed into that one; callers converted to use of complete_walk(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * consolidate nameidata_..._drop_rcu()Al Viro2011-05-261-105/+46
| | | | | | | | | | | | | | Merge these into a single function (unlazy_walk(nd, dentry)), kill ..._maybe variants Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | VFS: move BUG_ON test for symlink nd->depth after current->link_count testErez Zadok2011-05-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This solves a serious VFS-level bug in nested_symlink (which was rewritten from do_follow_link), and follows the order of depth tests that existed before. The bug triggers a BUG_ON in fs/namei.c:1381, when running racer with symlink and rename ops. Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu> Acked-by: Miklos Szeredi <mszeredi@suse.cz> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | vfs: micro-optimize acl_permission_check()Linus Torvalds2011-05-131-1/+1
|/ | | | | | | | | | | | | | It's a hot function, and we're better off not mixing types in the mask calculations. The compiler just ends up mixing 16-bit and 32-bit operations, for no good reason. So do everything in 'unsigned int' rather than mixing 'unsigned int' masking with a 'umode_t' (16-bit) mode variable. This, together with the parent commit (47a150edc2ae: "Cache user_ns in struct cred") makes acl_permission_check() much nicer. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>