Hi,
On Thursday 12 May 2016 16:42:31 Pranay Srivastava wrote:
> Hi Markus,
>
>
> On Thu, May 12, 2016 at 3:13 PM, Markus Pargmann <mpa@...1897...> wrote:
> > spinlocked ranges should be small and not contain calls into huge
> > subfunctions. Fix my mistake and just get the pointer to the socket
> > instead of doing everything with spinlock held.
> >
> > Reported-by: Mikulas Patocka <mikulas@...2380...>
> > Signed-off-by: Markus Pargmann <mpa@...1897...>
> > ---
> > drivers/block/nbd.c | 18 ++++++++++--------
> > 1 file changed, 10 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> > index 0b892eed06a0..157bf3da876e 100644
> > --- a/drivers/block/nbd.c
> > +++ b/drivers/block/nbd.c
> > @@ -173,20 +173,22 @@ static void nbd_end_request(struct nbd_device *nbd, struct request *req)
> > */
> > static void sock_shutdown(struct nbd_device *nbd)
> > {
> > + struct socket *sock;
> > +
> > spin_lock_irq(&nbd->sock_lock);
> > + sock = nbd->sock;
> > + nbd->sock = NULL;
> > + spin_unlock_irq(&nbd->sock_lock);
> >
> > - if (!nbd->sock) {
> > - spin_unlock_irq(&nbd->sock_lock);
> > + if (!sock)
> > return;
> > - }
> > +
> > + del_timer(&nbd->timeout_timer);
> >
> > dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
> > - kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
> > - sockfd_put(nbd->sock);
> > - nbd->sock = NULL;
> > - spin_unlock_irq(&nbd->sock_lock);
> > + kernel_sock_shutdown(sock, SHUT_RDWR);
> > + sockfd_put(sock);
> >
> > - del_timer(&nbd->timeout_timer);
> > }
> >
> > static void nbd_xmit_timeout(unsigned long arg)
>
> I was concerned about nbd_xmit_timeout as well. There's also a call to
> kernel_sock_shutdown,
> while holding the spin_lock in the timeout. The above is ok for
> sock_shutdown but some kind of change
> is also required in nbd_xmit_timeout as well. My patch addressed both these.
Oh I see thanks. Seems there is some duplicate code in
nbd_xmit_timeout and sock_shutdown. I think nbd_xmit_timeout could
perhaps be simplified?
static void nbd_xmit_timeout(unsigned long arg)
{
struct nbd_device *nbd = (struct nbd_device *)arg;
if (list_empty(&nbd->queue_head))
return;
nbd->timedout = true;
dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down connection\n");
sock_shutdown(nbd);
}
Thanks,
Markus
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