From 366f50133bb66bb368fb933c90f2dd2b07d35162 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Thu, 18 May 2017 17:28:49 +0200 Subject: xen/blkback: don't use xen_blkif_get() in xen-blkback kthread MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- drivers/block/xen-blkback/blkback.c | 3 --- drivers/block/xen-blkback/xenbus.c | 1 - 2 files changed, 4 deletions(-) diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c index 41fb1a917b17..33e23a7a691f 100644 --- a/drivers/block/xen-blkback/blkback.c +++ b/drivers/block/xen-blkback/blkback.c @@ -595,8 +595,6 @@ int xen_blkif_schedule(void *arg) unsigned long timeout; int ret; - xen_blkif_get(blkif); - while (!kthread_should_stop()) { if (try_to_freeze()) continue; @@ -650,7 +648,6 @@ purge_gnt_list: print_stats(blkif); blkif->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 58f151e283ff..923308201375 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -221,7 +221,6 @@ static int xen_blkif_disconnect(struct xen_blkif *blkif) if (blkif->xenblkd) { kthread_stop(blkif->xenblkd); wake_up(&blkif->shutdown_wq); - blkif->xenblkd = NULL; } /* The above kthread_stop() guarantees that at this point we -- cgit v1.2.3