pm24.git/ipc, branch v2.6.33-rc2

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

2009-12-16T20:04:02Z

* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (38 commits) direct I/O fallback sync simplification ocfs: stop using do_sync_mapping_range cleanup blockdev_direct_IO locking make generic_acl slightly more generic sanitize xattr handler prototypes libfs: move EXPORT_SYMBOL for d_alloc_name vfs: force reval of target when following LAST_BIND symlinks (try #7) ima: limit imbalance msg Untangling ima mess, part 3: kill dead code in ima Untangling ima mess, part 2: deal with counters Untangling ima mess, part 1: alloc_file() O_TRUNC open shouldn't fail after file truncation ima: call ima_inode_free ima_inode_free IMA: clean up the IMA counts updating code ima: only insert at inode creation time ima: valid return code from ima_inode_alloc fs: move get_empty_filp() deffinition to internal.h Sanitize exec_permission_lite() Kill cached_lookup() and real_lookup() Kill path_lookup_open() ... Trivial conflicts in fs/direct-io.c

Untangling ima mess, part 2: deal with counters

2009-12-16T17:16:47Z

* do ima_get_count() in __dentry_open() * stop doing that in followups * move ima_path_check() to right after nameidata_to_filp() * don't bump counters on it Signed-off-by: Al Viro

Untangling ima mess, part 1: alloc_file()

2009-12-16T17:16:47Z

There are 2 groups of alloc_file() callers: * ones that are followed by ima_counts_get * ones giving non-regular files So let's pull that ima_counts_get() into alloc_file(); it's a no-op in case of non-regular files. Signed-off-by: Al Viro

switch alloc_file() to passing struct path

2009-12-16T17:16:42Z

... and have the caller grab both mnt and dentry; kill leak in infiniband, while we are at it. Signed-off-by: Al Viro

ipc: remove unreachable code in sem.c

2009-12-16T15:20:10Z

This line is unreachable, remove it. [akpm@linux-foundation.org: remove unneeded initialisation of `err'] Signed-off-by: WANG Cong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc/sem.c: optimize single sops when semval is zero

2009-12-16T15:20:10Z

If multiple simple decrements on the same semaphore are pending, then the current code scans all decrement operations, even if the semaphore value is already 0. The patch optimizes that: if the semaphore value is 0, then there is no need to scan the q->alter entries. Note that this is a common case: It happens if 100 decrements by one are pending and now an increment by one increases the semaphore value from 0 to 1. Without this patch, all 100 entries are scanned. With the patch, only one entry is scanned, then woken up. Then the new rule triggers and the scanning is aborted, without looking at the remaining 99 tasks. With this patch, single sop increment/decrement by 1 are now O(1). (same as with Nick's patch) Signed-off-by: Manfred Spraul Cc: Nick Piggin Cc: Pierre Peiffer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc/sem.c: optimize single semop operations

2009-12-16T15:20:10Z

sysv sem has the concept of semaphore arrays that consist out of multiple semaphores. Atomic operations that affect multiple semaphores are supported. The patch optimizes single semaphore operation calls that affect only one semaphore: It's not necessary to scan all pending operations, it is sufficient to scan the per-semaphore list. The idea is from Nick Piggin version of an ipc sem improvement, the implementation is different: The code tries to keep as much common code as possible. As the result, the patch is simpler, but optimizes fewer cases. Signed-off-by: Manfred Spraul Cc: Nick Piggin Cc: Pierre Peiffer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc/sem.c: add a per-semaphore pending list

2009-12-16T15:20:10Z

Based on Nick's findings: sysv sem has the concept of semaphore arrays that consist out of multiple semaphores. Atomic operations that affect multiple semaphores are supported. The patch is the first step for optimizing simple, single semaphore operations: In addition to the global list of all pending operations, a 2nd, per-semaphore list with the simple operations is added. Note: this patch does not make sense by itself, the new list is used nowhere. Signed-off-by: Manfred Spraul Cc: Nick Piggin Cc: Pierre Peiffer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc/sem.c: optimize if semops fail

2009-12-16T15:20:09Z

Reduce the amount of scanning of the list of pending semaphore operations: If try_atomic_semop failed, then no changes were applied. Thus no need to restart. Additionally, this patch correct an incorrect comment: It's possible to wait for arbitrary semaphore values (do a dec by , wait-for-zero, inc by in one atomic operation) Both changes are from Nick Piggin, the patch is the result of a different split of the individual changes. Signed-off-by: Manfred Spraul Cc: Nick Piggin Cc: Pierre Peiffer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ipc/sem.c: sem preempt improve

2009-12-16T15:20:09Z

The strange sysv semaphore wakeup scheme has a kind of busy-wait lock involved, which could deadlock if preemption is enabled during the "lock". It is an implementation detail (due to a spinlock being held) that this is actually the case. However if "spinlocks" are made preemptible, or if the sem lock is changed to a sleeping lock for example, then the wakeup would become buggy. So this might be a bugfix for -rt kernels. Imagine waker being preempted by wakee and never clearing IN_WAKEUP -- if wakee has higher RT priority then there is a priority inversion deadlock. Even if there is not a priority inversion to cause a deadlock, then there is still time wasted spinning. Signed-off-by: Nick Piggin Signed-off-by: Manfred Spraul Cc: Pierre Peiffer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds