From 22945e4a1c7454c97f5d8aee1ef526c83fef3223 Mon Sep 17 00:00:00 2001 From: Tom Tucker Date: Mon, 5 Jan 2009 15:21:19 -0600 Subject: svc: Clean up deferred requests on transport destruction A race between svc_revisit and svc_delete_xprt can result in deferred requests holding references on a transport that can never be recovered because dead transports are not enqueued for subsequent processing. Check for XPT_DEAD in revisit to clean up completing deferrals on a dead transport and sweep a transport's deferred queue to do the same for queued but unprocessed deferrals. Signed-off-by: Tom Tucker Signed-off-by: J. Bruce Fields --- net/sunrpc/svc_xprt.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 29619612b9f..a78b87937c7 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -850,6 +850,11 @@ static void svc_age_temp_xprts(unsigned long closure) void svc_delete_xprt(struct svc_xprt *xprt) { struct svc_serv *serv = xprt->xpt_server; + struct svc_deferred_req *dr; + + /* Only do this once */ + if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags)) + return; dprintk("svc: svc_delete_xprt(%p)\n", xprt); xprt->xpt_ops->xpo_detach(xprt); @@ -864,12 +869,16 @@ void svc_delete_xprt(struct svc_xprt *xprt) * while still attached to a queue, the queue itself * is about to be destroyed (in svc_destroy). */ - if (!test_and_set_bit(XPT_DEAD, &xprt->xpt_flags)) { - BUG_ON(atomic_read(&xprt->xpt_ref.refcount) < 2); - if (test_bit(XPT_TEMP, &xprt->xpt_flags)) - serv->sv_tmpcnt--; + if (test_bit(XPT_TEMP, &xprt->xpt_flags)) + serv->sv_tmpcnt--; + + for (dr = svc_deferred_dequeue(xprt); dr; + dr = svc_deferred_dequeue(xprt)) { svc_xprt_put(xprt); + kfree(dr); } + + svc_xprt_put(xprt); spin_unlock_bh(&serv->sv_lock); } @@ -915,17 +924,19 @@ static void svc_revisit(struct cache_deferred_req *dreq, int too_many) container_of(dreq, struct svc_deferred_req, handle); struct svc_xprt *xprt = dr->xprt; - if (too_many) { + spin_lock(&xprt->xpt_lock); + set_bit(XPT_DEFERRED, &xprt->xpt_flags); + if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) { + spin_unlock(&xprt->xpt_lock); + dprintk("revisit canceled\n"); svc_xprt_put(xprt); kfree(dr); return; } dprintk("revisit queued\n"); dr->xprt = NULL; - spin_lock(&xprt->xpt_lock); list_add(&dr->handle.recent, &xprt->xpt_deferred); spin_unlock(&xprt->xpt_lock); - set_bit(XPT_DEFERRED, &xprt->xpt_flags); svc_xprt_enqueue(xprt); svc_xprt_put(xprt); } -- cgit v1.2.3-70-g09d2