From: Juergen Gross Date: Thu, 18 May 2017 15:28:49 +0000 (+0200) Subject: xen/blkback: don't use xen_blkif_get() in xen-blkback kthread X-Git-Tag: android-x86-7.1-r1~25^2~173^2~142 X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=8dc9f9dede5b92658a1bb32866e11905933d2b48;p=android-x86%2Fkernel.git xen/blkback: don't use xen_blkif_get() in xen-blkback kthread commit a24fa22ce22ae302b3bf8f7008896d52d5d57b8d upstream. There is no need to use xen_blkif_get()/xen_blkif_put() in the kthread of xen-blkback. Thread stopping is synchronous and using the blkif reference counting in the kthread will avoid to ever let the reference count drop to zero at the end of an I/O running concurrent to disconnecting and multiple rings. Setting ring->xenblkd to NULL after stopping the kthread isn't needed as the kthread does this already. Signed-off-by: Juergen Gross Tested-by: Steven Haigh Acked-by: Roger Pau Monné Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index c42202d63567..d6eaaa25d1cc 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -609,8 +609,6 @@ int xen_blkif_schedule(void *arg) unsigned long timeout; int ret; - xen_blkif_get(blkif); - set_freezable(); while (!kthread_should_stop()) { if (try_to_freeze()) @@ -665,7 +663,6 @@ purge_gnt_list: print_stats(ring); ring->xenblkd = NULL; - xen_blkif_put(blkif); return 0; } diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 9b69fe410c08..d8fc9c58e2a3 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -255,7 +255,6 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif) if (ring->xenblkd) { kthread_stop(ring->xenblkd); wake_up(&ring->shutdown_wq); - ring->xenblkd = NULL; } /* The above kthread_stop() guarantees that at this point we