Messages in this thread Patch in this message | | | Date | Mon, 04 Mar 2013 03:38:11 +0000 | From | Ben Hutchings <> | Subject | [ 064/153] svcrpc: make svc_age_temp_xprts enqueue under sv_lock |
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3.2-stable review patch. If anyone has any objections, please let me know.
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From: "J. Bruce Fields" <bfields@redhat.com>
commit e75bafbff2270993926abcc31358361db74a9bc2 upstream.
svc_age_temp_xprts expires xprts in a two-step process: first it takes the sv_lock and moves the xprts to expire off their server-wide list (sv_tempsocks or sv_permsocks) to a local list. Then it drops the sv_lock and enqueues and puts each one.
I see no reason for this: svc_xprt_enqueue() will take sp_lock, but the sv_lock and sp_lock are not otherwise nested anywhere (and documentation at the top of this file claims it's correct to nest these with sp_lock inside.)
Tested-by: Jason Tibbitts <tibbs@math.uh.edu> Tested-by: PaweÅ Sikora <pawel.sikora@agmk.net> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- net/sunrpc/svc_xprt.c | 15 ++------------- 1 file changed, 2 insertions(+), 13 deletions(-)
--- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -816,7 +816,6 @@ static void svc_age_temp_xprts(unsigned struct svc_serv *serv = (struct svc_serv *)closure; struct svc_xprt *xprt; struct list_head *le, *next; - LIST_HEAD(to_be_aged); dprintk("svc_age_temp_xprts\n"); @@ -837,25 +836,15 @@ static void svc_age_temp_xprts(unsigned if (atomic_read(&xprt->xpt_ref.refcount) > 1 || test_bit(XPT_BUSY, &xprt->xpt_flags)) continue; - svc_xprt_get(xprt); - list_move(le, &to_be_aged); + list_del_init(le); set_bit(XPT_CLOSE, &xprt->xpt_flags); set_bit(XPT_DETACHED, &xprt->xpt_flags); - } - spin_unlock_bh(&serv->sv_lock); - - while (!list_empty(&to_be_aged)) { - le = to_be_aged.next; - /* fiddling the xpt_list node is safe 'cos we're XPT_DETACHED */ - list_del_init(le); - xprt = list_entry(le, struct svc_xprt, xpt_list); - dprintk("queuing xprt %p for closing\n", xprt); /* a thread will dequeue and close it soon */ svc_xprt_enqueue(xprt); - svc_xprt_put(xprt); } + spin_unlock_bh(&serv->sv_lock); mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ); }
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