dm thin: remap the bios in a cell immediately
authorJoe Thornber <ejt@redhat.com>
Fri, 10 Oct 2014 14:27:16 +0000 (15:27 +0100)
committerMike Snitzer <snitzer@redhat.com>
Mon, 10 Nov 2014 20:25:28 +0000 (15:25 -0500)
commit2d759a46b4d65e1392843cf9df7101897af87008
tree7cca57c04d5d8e29ca7ae232fa52f2e8fa6883c3
parenta374bb217b449a00eb96d0584bb833a8b62b672a
dm thin: remap the bios in a cell immediately

This use of direct submission in process_prepared_mapping() reduces
latency for submitting bios in a cell by avoiding adding those bios to
the deferred list and waiting for the next iteration of the worker.

But this direct submission exposes the potential for a race between
releasing a cell and incrementing deferred set.  Fix this by introducing
dm_cell_visit_release() and refactoring inc_remap_and_issue_cell()
accordingly.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
drivers/md/dm-bio-prison.c
drivers/md/dm-bio-prison.h
drivers/md/dm-thin.c