Bruce,
This patch replaces 2/3 of Trond's deferral cleanup patch. This shouldn't
come across with the white-spaced munged. Please let me know if it does.
Thanks,
Tom
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 <[email protected]>
---
net/sunrpc/svc_xprt.c | 25 ++++++++++++++++++-------
1 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index bf5b5cd..e6e7e25 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -837,6 +837,11 @@ 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);
@@ -851,12 +856,16 @@ 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);
}
@@ -902,17 +911,19 @@ 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);
}
On Mon, Jan 05, 2009 at 03:21:19PM -0600, Tom Tucker wrote:
> Bruce,
>
> This patch replaces 2/3 of Trond's deferral cleanup patch. This shouldn't
By that you mean patches 2 and 3, right?
--b.
> come across with the white-spaced munged. Please let me know if it does.
>
> Thanks,
> Tom
>
> 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 <[email protected]>
>
> ---
> net/sunrpc/svc_xprt.c | 25 ++++++++++++++++++-------
> 1 files changed, 18 insertions(+), 7 deletions(-)
>
> diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> index bf5b5cd..e6e7e25 100644
> --- a/net/sunrpc/svc_xprt.c
> +++ b/net/sunrpc/svc_xprt.c
> @@ -837,6 +837,11 @@ 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);
> @@ -851,12 +856,16 @@ 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);
> }
>
> @@ -902,17 +911,19 @@ 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);
> }
On Wed, Jan 07, 2009 at 05:00:28PM -0500, bfields wrote:
> On Mon, Jan 05, 2009 at 03:21:19PM -0600, Tom Tucker wrote:
> > Bruce,
> >
> > This patch replaces 2/3 of Trond's deferral cleanup patch. This shouldn't
>
> By that you mean patches 2 and 3, right?
Must be. Anyway, applied.
> > come across with the white-spaced munged. Please let me know if it does.
It seems to have arrived with an extra space at the beginning of each
context line (each line not beginning with a +/-). With that fixed, it
applies cleanly.
--b.
> >
> > Thanks,
> > Tom
> >
> > 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 <[email protected]>
> >
> > ---
> > net/sunrpc/svc_xprt.c | 25 ++++++++++++++++++-------
> > 1 files changed, 18 insertions(+), 7 deletions(-)
> >
> > diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
> > index bf5b5cd..e6e7e25 100644
> > --- a/net/sunrpc/svc_xprt.c
> > +++ b/net/sunrpc/svc_xprt.c
> > @@ -837,6 +837,11 @@ 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);
> > @@ -851,12 +856,16 @@ 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);
> > }
> >
> > @@ -902,17 +911,19 @@ 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);
> > }