diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2006-01-04 20:31:21 +0100 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2006-01-09 15:44:35 +1100 |
| commit | 762cf6dac2623473e83bb271f2bbe97d2355c64d (patch) | |
| tree | 51871b65240062fc9442965923f710f0782b4e34 | |
| parent | c902be71dc6d5e8473bd021feafc8c3608e2b82a (diff) | |
[PATCH] spufs: fix locking in spu_acquire_runnable
We need to check for validity of owner under down_write,
down_read is not enough.
Noticed by Al Viro.
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
| -rw-r--r-- | arch/powerpc/platforms/cell/spufs/context.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c index 1758cec58bc7..903c35d19577 100644 --- a/arch/powerpc/platforms/cell/spufs/context.c +++ b/arch/powerpc/platforms/cell/spufs/context.c @@ -120,27 +120,29 @@ int spu_acquire_runnable(struct spu_context *ctx) ctx->spu->prio = current->prio; return 0; } + up_read(&ctx->state_sema); + + down_write(&ctx->state_sema); /* ctx is about to be freed, can't acquire any more */ if (!ctx->owner) { ret = -EINVAL; goto out; } - up_read(&ctx->state_sema); - down_write(&ctx->state_sema); if (ctx->state == SPU_STATE_SAVED) { ret = spu_activate(ctx, 0); ctx->state = SPU_STATE_RUNNABLE; } - downgrade_write(&ctx->state_sema); if (ret) goto out; + downgrade_write(&ctx->state_sema); /* On success, we return holding the lock */ + return ret; out: /* Release here, to simplify calling code. */ - up_read(&ctx->state_sema); + up_write(&ctx->state_sema); return ret; } |