linux/ipc, branch v3.11.9

ipc/sem.c: update sem_otime for all operations

2013-10-18T17:55:02Z

commit 0e8c665699e953fa58dc1b0b0d09e5dce7343cc7 upstream. In commit 0a2b9d4c7967 ("ipc/sem.c: move wake_up_process out of the spinlock section"), the update of semaphore's sem_otime(last semop time) was moved to one central position (do_smart_update). But since do_smart_update() is only called for operations that modify the array, this means that wait-for-zero semops do not update sem_otime anymore. The fix is simple: Non-alter operations must update sem_otime. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Manfred Spraul Reported-by: Jia He Tested-by: Jia He Cc: Davidlohr Bueso Cc: Mike Galbraith Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

ipc/sem.c: synchronize the proc interface

2013-10-18T17:55:02Z

commit d8c633766ad88527f25d9f81a5c2f083d78a2b39 upstream. The proc interface is not aware of sem_lock(), it instead calls ipc_lock_object() directly. This means that simple semop() operations can run in parallel with the proc interface. Right now, this is uncritical, because the implementation doesn't do anything that requires a proper synchronization. But it is dangerous and therefore should be fixed. Signed-off-by: Manfred Spraul Cc: Davidlohr Bueso Cc: Mike Galbraith Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

ipc/sem.c: optimize sem_lock()

2013-10-18T17:55:02Z

commit 6d07b68ce16ae9535955ba2059dedba5309c3ca1 upstream. Operations that need access to the whole array must guarantee that there are no simple operations ongoing. Right now this is achieved by spin_unlock_wait(sem->lock) on all semaphores. If complex_count is nonzero, then this spin_unlock_wait() is not necessary, because it was already performed in the past by the thread that increased complex_count and even though sem_perm.lock was dropped inbetween, no simple operation could have started, because simple operations cannot start when complex_count is non-zero. Signed-off-by: Manfred Spraul Cc: Mike Galbraith Cc: Rik van Riel Reviewed-by: Davidlohr Bueso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Mike Galbraith Signed-off-by: Greg Kroah-Hartman

ipc: drop ipc_lock_check

2013-10-18T17:55:02Z

commit 20b8875abcf2daa1dda5cf70bd6369df5e85d4c1 upstream. No remaining users, we now use ipc_obtain_object_check(). Signed-off-by: Davidlohr Bueso Cc: Sedat Dilek Cc: Rik van Riel Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Mike Galbraith Signed-off-by: Greg Kroah-Hartman

ipc, shm: drop shm_lock_check

2013-10-18T17:55:01Z

commit 7a25dd9e042b2b94202a67e5551112f4ac87285a upstream. This function was replaced by a the lockless shm_obtain_object_check(), and no longer has any users. Signed-off-by: Davidlohr Bueso Cc: Sedat Dilek Cc: Rik van Riel Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Mike Galbraith Signed-off-by: Greg Kroah-Hartman

ipc: drop ipc_lock_by_ptr

2013-10-18T17:55:01Z

commit 32a2750010981216fb788c5190fb0e646abfab30 upstream. After previous cleanups and optimizations, this function is no longer heavily used and we don't have a good reason to keep it. Update the few remaining callers and get rid of it. Signed-off-by: Davidlohr Bueso Cc: Sedat Dilek Cc: Rik van Riel Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Mike Galbraith Signed-off-by: Greg Kroah-Hartman

ipc, shm: guard against non-existant vma in shmdt(2)

2013-10-18T17:55:01Z

commit 530fcd16d87cd2417c472a581ba5a1e501556c86 upstream. When !CONFIG_MMU there's a chance we can derefence a NULL pointer when the VM area isn't found - check the return value of find_vma(). Also, remove the redundant -EINVAL return: retval is set to the proper return code and *only* changed to 0, when we actually unmap the segments. Signed-off-by: Davidlohr Bueso Cc: Sedat Dilek Cc: Rik van Riel Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Mike Galbraith Signed-off-by: Greg Kroah-Hartman

ipc: document general ipc locking scheme

2013-10-18T17:55:01Z

commit 05603c44a7627793219b0bd9a7b236099dc9cd9d upstream. As suggested by Andrew, add a generic initial locking scheme used throughout all sysv ipc mechanisms. Documenting the ids rwsem, how rcu can be enough to do the initial checks and when to actually acquire the kern_ipc_perm.lock spinlock. I found that adding it to util.c was generic enough. Signed-off-by: Davidlohr Bueso Tested-by: Sedat Dilek Cc: Rik van Riel Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Mike Galbraith Signed-off-by: Greg Kroah-Hartman

ipc,msg: drop msg_unlock

2013-10-18T17:55:01Z

commit 4718787d1f626f45ddb239912bc07266b9880044 upstream. There is only one user left, drop this function and just call ipc_unlock_object() and rcu_read_unlock(). Signed-off-by: Davidlohr Bueso Tested-by: Sedat Dilek Cc: Rik van Riel Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Mike Galbraith Signed-off-by: Greg Kroah-Hartman

ipc: rename ids->rw_mutex

2013-10-18T17:55:00Z

commit d9a605e40b1376eb02b067d7690580255a0df68f upstream. Since in some situations the lock can be shared for readers, we shouldn't be calling it a mutex, rename it to rwsem. Signed-off-by: Davidlohr Bueso Tested-by: Sedat Dilek Cc: Rik van Riel Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Mike Galbraith Signed-off-by: Greg Kroah-Hartman