Messages in this thread Patch in this message | | | Date | Tue, 25 May 2010 11:09:19 -0700 | From | Greg KH <> | Subject | [21/25] svc: Clean up deferred requests on transport destruction |
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2.6.27-stable review patch. If anyone has any objections, please let us know.
------------------ From: Tom Tucker <tom@opengridcomputing.com>
commit 22945e4a1c7454c97f5d8aee1ef526c83fef3223 upstream.
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 <tom@opengridcomputing.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Cc: roma1390 <roma1390@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- net/sunrpc/svc_xprt.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-)
--- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -810,6 +810,11 @@ static void svc_age_temp_xprts(unsigned 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); @@ -824,12 +829,16 @@ void svc_delete_xprt(struct svc_xprt *xp * 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); } @@ -875,17 +884,19 @@ static void svc_revisit(struct cache_def 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); }
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