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authorNeilBrown <neilb@suse.de>2010-11-15 11:27:01 +1100
committerJ. Bruce Fields <bfields@redhat.com>2010-12-17 15:48:18 -0500
commit7c96aef75949a56ec427fc6a2522dace2af33605 (patch)
treeca65368231d4c5b39e3adce558bfe15d712809c7 /net/sunrpc
parent18b631f83810e95eeb2e1839889b27142bd8d6d8 (diff)
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sunrpc: remove xpt_pool
The xpt_pool field is only used for reporting BUGs. And it isn't used correctly. In particular, when it is cleared in svc_xprt_received before XPT_BUSY is cleared, there is no guarantee that either the compiler or the CPU might not re-order to two assignments, just setting xpt_pool to NULL after XPT_BUSY is cleared. If a different cpu were running svc_xprt_enqueue at this moment, it might see XPT_BUSY clear and then xpt_pool non-NULL, and so BUG. This could be fixed by calling smp_mb__before_clear_bit() before the clear_bit. However as xpt_pool isn't really used, it seems safest to simply remove xpt_pool. Another alternate would be to change the clear_bit to clear_bit_unlock, and the test_and_set_bit to test_and_set_bit_lock. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Diffstat (limited to 'net/sunrpc')
-rw-r--r--net/sunrpc/svc_xprt.c5
1 files changed, 0 insertions, 5 deletions
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 5a75d23645c8..5eae53b1e306 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -351,8 +351,6 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
dprintk("svc: transport %p busy, not enqueued\n", xprt);
goto out_unlock;
}
- BUG_ON(xprt->xpt_pool != NULL);
- xprt->xpt_pool = pool;
if (!list_empty(&pool->sp_threads)) {
rqstp = list_entry(pool->sp_threads.next,
@@ -370,13 +368,11 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
rqstp->rq_reserved = serv->sv_max_mesg;
atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
pool->sp_stats.threads_woken++;
- BUG_ON(xprt->xpt_pool != pool);
wake_up(&rqstp->rq_wait);
} else {
dprintk("svc: transport %p put into queue\n", xprt);
list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
pool->sp_stats.sockets_queued++;
- BUG_ON(xprt->xpt_pool != pool);
}
out_unlock:
@@ -415,7 +411,6 @@ static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
void svc_xprt_received(struct svc_xprt *xprt)
{
BUG_ON(!test_bit(XPT_BUSY, &xprt->xpt_flags));
- xprt->xpt_pool = NULL;
/* As soon as we clear busy, the xprt could be closed and
* 'put', so we need a reference to call svc_xprt_enqueue with:
*/