From 2af537a46a766b0ef085b4d8b1f28e8c40ba2a20 Mon Sep 17 00:00:00 2001 From: Boris Ostrovsky Date: Sat, 22 Sep 2018 15:55:49 -0400 Subject: [PATCH] xen/blkfront: When purging persistent grants, keep them in the buffer Commit f1d787e4e8ba ("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: f1d787e4e8ba ("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(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index a71d817e900dd..3b441fe69c0dd 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); -- 2.39.5