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authorChristoph Hellwig <hch@lst.de>2015-08-27 14:16:54 +0200
committerJames Bottomley <JBottomley@Odin.com>2015-08-28 13:14:54 -0700
commit1bab0de0274fbe8c8ac92179e6705584c55ed169 (patch)
tree3a2bbd51706e6ec0a279cbc0011d996de7320aa7 /drivers/md/dm-mpath.c
parent36dd5acd196574d41de3e81d8264df475bbb7123 (diff)
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dm-mpath, scsi_dh: don't let dm detach device handlers
While allowing dm-mpath to attach device handlers is a functionality we need for backwards compatibility reason there is no reason to reference count them and detach them if dm-mpath stops using the device for some reason. If the device handler works for the given device it can just stay attached, and we can take the retain_hw_handler codepath. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Hannes Reinecke <hare@Suse.de> Signed-off-by: James Bottomley <JBottomley@Odin.com>
Diffstat (limited to 'drivers/md/dm-mpath.c')
-rw-r--r--drivers/md/dm-mpath.c21
1 files changed, 6 insertions, 15 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index eff7bdd7731d..a9f58fdb5d69 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -159,12 +159,9 @@ static struct priority_group *alloc_priority_group(void)
static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
{
struct pgpath *pgpath, *tmp;
- struct multipath *m = ti->private;
list_for_each_entry_safe(pgpath, tmp, pgpaths, list) {
list_del(&pgpath->list);
- if (m->hw_handler_name)
- scsi_dh_detach(bdev_get_queue(pgpath->path.dev->bdev));
dm_put_device(ti, pgpath->path.dev);
free_pgpath(pgpath);
}
@@ -580,6 +577,7 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
q = bdev_get_queue(p->path.dev->bdev);
if (m->retain_attached_hw_handler) {
+retain:
attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL);
if (attached_handler_name) {
/*
@@ -599,20 +597,14 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
}
if (m->hw_handler_name) {
- /*
- * Increments scsi_dh reference, even when using an
- * already-attached handler.
- */
r = scsi_dh_attach(q, m->hw_handler_name);
if (r == -EBUSY) {
- /*
- * Already attached to different hw_handler:
- * try to reattach with correct one.
- */
- scsi_dh_detach(q);
- r = scsi_dh_attach(q, m->hw_handler_name);
- }
+ char b[BDEVNAME_SIZE];
+ printk(KERN_INFO "dm-mpath: retaining handler on device %s\n",
+ bdevname(p->path.dev->bdev, b));
+ goto retain;
+ }
if (r < 0) {
ti->error = "error attaching hardware handler";
dm_put_device(ti, p->path.dev);
@@ -624,7 +616,6 @@ static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps
if (r < 0) {
ti->error = "unable to set hardware "
"handler parameters";
- scsi_dh_detach(q);
dm_put_device(ti, p->path.dev);
goto bad;
}