From f151ba989d149bbdfc90e5405724bbea094f9b17 Mon Sep 17 00:00:00 2001 From: Boris Ostrovsky Date: Sat, 22 Sep 2018 15:55:49 -0400 Subject: xen/blkfront: When purging persistent grants, keep them in the buffer Commit a46b53672b2c ("xen/blkfront: cleanup stale persistent grants") added support for purging persistent grants when they are not in use. As part of the purge, the grants were removed from the grant buffer, This eventually causes the buffer to become empty, with BUG_ON triggered in get_free_grant(). This can be observed even on an idle system, within 20-30 minutes. We should keep the grants in the buffer when purging, and only free the grant ref. Fixes: a46b53672b2c ("xen/blkfront: cleanup stale persistent grants") Reviewed-by: Juergen Gross Signed-off-by: Boris Ostrovsky Signed-off-by: Jens Axboe --- drivers/block/xen-blkfront.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'drivers/block/xen-blkfront.c') diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index a71d817e900d..3b441fe69c0d 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -2667,11 +2667,9 @@ static void purge_persistent_grants(struct blkfront_info *info) gnttab_query_foreign_access(gnt_list_entry->gref)) continue; - list_del(&gnt_list_entry->node); gnttab_end_foreign_access(gnt_list_entry->gref, 0, 0UL); + gnt_list_entry->gref = GRANT_INVALID_REF; rinfo->persistent_gnts_c--; - __free_page(gnt_list_entry->page); - kfree(gnt_list_entry); } spin_unlock_irqrestore(&rinfo->ring_lock, flags); -- cgit v1.2.3-59-g8ed1b From 15c206887603a452f13fbfde2db0f8830d37028c Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 28 Sep 2018 09:40:17 -0600 Subject: Revert "xen/blkfront: When purging persistent grants, keep them in the buffer" Fix didn't work for all cases, reverting to add a (hopefully) better fix. This reverts commit f151ba989d149bbdfc90e5405724bbea094f9b17. Signed-off-by: Jens Axboe --- drivers/block/xen-blkfront.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/block/xen-blkfront.c') diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 3b441fe69c0d..a71d817e900d 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -2667,9 +2667,11 @@ static void purge_persistent_grants(struct blkfront_info *info) gnttab_query_foreign_access(gnt_list_entry->gref)) continue; + list_del(&gnt_list_entry->node); gnttab_end_foreign_access(gnt_list_entry->gref, 0, 0UL); - gnt_list_entry->gref = GRANT_INVALID_REF; rinfo->persistent_gnts_c--; + __free_page(gnt_list_entry->page); + kfree(gnt_list_entry); } spin_unlock_irqrestore(&rinfo->ring_lock, flags); -- cgit v1.2.3-59-g8ed1b From 6c7678674014b4552caf0e5aa0ca34078a377482 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Fri, 28 Sep 2018 09:28:27 +0200 Subject: xen/blkfront: correct purging of persistent grants Commit a46b53672b2c2e3770b38a4abf90d16364d2584b ("xen/blkfront: cleanup stale persistent grants") introduced a regression as purged persistent grants were not pu into the list of free grants again. Correct that. Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross Signed-off-by: Jens Axboe --- drivers/block/xen-blkfront.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/block/xen-blkfront.c') diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index a71d817e900d..429d20131c7e 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -2670,8 +2670,8 @@ static void purge_persistent_grants(struct blkfront_info *info) list_del(&gnt_list_entry->node); gnttab_end_foreign_access(gnt_list_entry->gref, 0, 0UL); rinfo->persistent_gnts_c--; - __free_page(gnt_list_entry->page); - kfree(gnt_list_entry); + gnt_list_entry->gref = GRANT_INVALID_REF; + list_add_tail(&gnt_list_entry->node, &rinfo->grants); } spin_unlock_irqrestore(&rinfo->ring_lock, flags); -- cgit v1.2.3-59-g8ed1b