linux-toradex.git/include/linux/sem.h, branch v2.6.36-rc5

ipc/sem.c: cacheline align the ipc spinlock for semaphores

2010-05-27T16:12:49+00:00

Cacheline align the spinlock for sysv semaphores.  Without the patch, the
spinlock and sem_otime [written by every semop that modified the array]
and sem_base [read in the hot path of try_atomic_semop()] can be in the
same cacheline.

Signed-off-by: Manfred Spraul 
Cc: Chris Mason 
Cc: Zach Brown 
Cc: Jens Axboe 
Cc: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

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

2009-12-16T15:20:10+00:00

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: rewrite undo list locking

2008-07-25T17:53:42+00:00

The attached patch:
- reverses the locking order of ulp->lock and sem_lock:
  Previously, it was first ulp->lock, then inside sem_lock.
  Now it's the other way around.
- converts the undo structure to rcu.

Benefits:
- With the old locking order, IPC_RMID could not kfree the undo structures.
  The stale entries remained in the linked lists and were released later.
- The patch fixes a a race in semtimedop(): if both IPC_RMID and a semget() that
  recreates exactly the same id happen between find_alloc_undo() and sem_lock,
  then semtimedop() would access already kfree'd memory.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Manfred Spraul 
Reviewed-by: Nadia Derbey 
Cc: Pierre Peiffer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc/sem.c: convert sem_array.sem_pending to struct list_head

2008-07-25T17:53:42+00:00

sem_array.sem_pending is a double linked list, the attached patch converts
it to struct list_head.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Manfred Spraul 
Reviewed-by: Nadia Derbey 
Cc: Pierre Peiffer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc/sem.c: remove unused entries from struct sem_queue

2008-07-25T17:53:42+00:00

sem_queue.sma and sem_queue.id were never used, the attached patch removes
them.

Signed-off-by: Manfred Spraul 
Reviewed-by: Nadia Derbey 
Cc: Pierre Peiffer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc/sem.c: convert undo structures to struct list_head

2008-07-25T17:53:42+00:00

The undo structures contain two linked lists, the attached patch replaces
them with generic struct list_head lists.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Manfred Spraul 
Cc: Nadia Derbey 
Cc: Pierre Peiffer 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ipc: store ipcs into IDRs

2007-10-19T18:53:44+00:00

This patch introduces ipcs storage into IDRs. The main changes are:
  . This ipc_ids structure is changed: the entries array is changed into a
    root idr structure.
  . The grow_ary() routine is removed: it is not needed anymore when adding
    an ipc structure, since we are now using the IDR facility.
  . The ipc_rmid() routine interface is changed:
       . there is no need for this routine to return the pointer passed in as
         argument: it is now declared as a void
       . since the id is now part of the kern_ipc_perm structure, no need to
         have it as an argument to the routine

Signed-off-by: Nadia Derbey 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Don't include from user-visible part of linux/sem.h

2006-04-25T13:55:13+00:00

Signed-off-by: David Woodhouse

[PATCH] fix remaining missing includes

2005-11-07T15:53:41+00:00

Fix more include file problems that surfaced since I submitted the previous
fix-missing-includes.patch.  This should now allow not to include sched.h
from module.h, which is done by a followup patch.

Signed-off-by: Tim Schmielau 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] ipc: convert /proc/sysvipc/* to generic seq_file interface

2005-09-07T23:57:26+00:00

Change the /proc/sysvipc/shm|sem|msg files to use the generic seq_file
implementation for struct ipc_ids.

Signed-off-by: Mike Waychison 
Cc: Manfred Spraul 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds