From: Joe Thornber Date: Fri, 23 Jan 2015 10:16:16 +0000 (+0000) Subject: dm cache: fix problematic dual use of a single migration count variable X-Git-Tag: omap-for-v4.1/prcm-dts-mfd-syscon-fix~232^2~1 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a59db67656021fa212e9b95a583f13c34eb67cd9;p=pandora-kernel.git dm cache: fix problematic dual use of a single migration count variable Introduce a new variable to count the number of allocated migration structures. The existing variable cache->nr_migrations became overloaded. It was used to: i) track of the number of migrations in flight for the purposes of quiescing during suspend. ii) to estimate the amount of background IO occuring. Recent discard changes meant that REQ_DISCARD bios are processed with a migration. Discards are not background IO so nr_migrations was not incremented. However this could cause quiescing to complete early. (i) is now handled with a new variable cache->nr_allocated_migrations. cache->nr_migrations has been renamed cache->nr_io_migrations. cleanup_migration() is now called free_io_migration(), since it decrements that variable. Also, remove the unused cache->next_migration variable that got replaced with with prealloc_structs a while ago. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer Cc: stable@vger.kernel.org --- Reading git-diff-tree failed