On Mon, 25 Mar 2013 16:21:22 -0400
Sasha Levin <sasha.le...@oracle.com> wrote:
> On 03/20/2013 03:55 PM, Rik van Riel wrote:
> > Include lkml in the CC: this time... *sigh*
> > ---8<---
> >
> > This series makes the sysv semaphore code more scalable,
> > by reducing the time the semaphore lock is held, and making
> > the locking more scalable for semaphore arrays with multiple
> > semaphores.
>
> Hi Rik,
>
> I'm getting the following false positives from lockdep:
Does this patch fix it?
Andrew, this looks like another one for the queue...
---8<---
Subject: [PATCH -mm -next] ipc,sem: fix lockdep false positive
When locking all the semaphores inside a sem_array, the kernel ends up
locking a large number of locks with identical lockdep status. This
trips up lockdep. Annotate the code to prevent such warnings.
Signed-off-by: Rik van Riel <r...@redhat.com>
---
ipc/sem.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/ipc/sem.c b/ipc/sem.c
index 450248e..f46441a 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -357,7 +357,7 @@ static inline int sem_lock(struct sem_array *sma, struct
sembuf *sops,
spin_lock(&sma->sem_perm.lock);
for (i = 0; i < sma->sem_nsems; i++) {
struct sem *sem = sma->sem_base + i;
- spin_lock(&sem->lock);
+ spin_lock_nested(&sem->lock, SINGLE_DEPTH_NESTING);
}
locknum = -1;
}
@@ -558,7 +558,7 @@ static int newary(struct ipc_namespace *ns, struct
ipc_params *params)
for (i = 0; i < nsems; i++) {
INIT_LIST_HEAD(&sma->sem_base[i].sem_pending);
spin_lock_init(&sma->sem_base[i].lock);
- spin_lock(&sma->sem_base[i].lock);
+ spin_lock_nested(&sma->sem_base[i].lock, SINGLE_DEPTH_NESTING);
}
sma->complex_count = 0;
--
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