svcrpc: make svc_age_temp_xprts enqueue under sv_lock

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.)

Cc: stable@kernel.org
Tested-by: Jason Tibbitts <tibbs@math.uh.edu>
Tested-by: Paweł Sikora <pawel.sikora@agmk.net>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields 2013-02-10 11:33:48 -05:00
parent f25cc71e63
commit e75bafbff2

View File

@ -863,7 +863,6 @@ static void svc_age_temp_xprts(unsigned long closure)
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");
@ -884,25 +883,15 @@ static void svc_age_temp_xprts(unsigned long closure)
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);
}