ipc,sem: fix semctl(..., GETZCNT)
authorRik van Riel <riel@redhat.com>
Thu, 9 May 2013 20:53:28 +0000 (16:53 -0400)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 9 May 2013 21:17:47 +0000 (14:17 -0700)
commitebc2e5e6a408a0e6ed63c0ba98c2c8a232c6b4f4
treeeb376fff2b32ae63b6d5ba8faac2f26a899d51df
parent07e074503eba3ee657ab50a8c9497ddf90039e7e
ipc,sem: fix semctl(..., GETZCNT)

The semctl GETZCNT returns the number of semops waiting for the
specified semaphore to become zero.  After commit 9f1bc2c9022c
("ipc,sem: have only one list in struct sem_queue"), the semops waiting
on just one semaphore are waiting on that semaphore's list.

In order to return the correct count, we have to walk that list too, in
addition to the sem_array's list for complex operations.

This bug broke dbench; it works again with this patch applied.

Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Kent Overstreet <koverstreet@google.com>
Tested-by: Kent Overstreet <koverstreet@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc/sem.c