dm rq: change ->rq_end_io calling conventions

Instead of returning either a DM_ENDIO_* constant or an error code, add
a new DM_ENDIO_DONE value that means keep errno as is.  This allows us
to easily keep the existing error code in case where we can't push back,
and it also preparares for the new block level status codes with strict
type checking.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 8b394a08d4271bc9f5cde847043c99e4e283d827..926a6bcb32c8600118696119fd8ebe521cadbe5e 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1469,6 +1469,7 @@ static int multipath_end_io(struct dm_target *ti, struct request *clone,
 {
        struct dm_mpath_io *mpio = get_mpio(map_context);
        struct pgpath *pgpath = mpio->pgpath;
+       int r = DM_ENDIO_DONE;
 
        /*
         * We don't queue any clone request inside the multipath target
@@ -1484,14 +1485,18 @@ static int multipath_end_io(struct dm_target *ti, struct request *clone,
        if (error && !noretry_error(error)) {
                struct multipath *m = ti->private;
 
-               error = DM_ENDIO_REQUEUE;
+               r = DM_ENDIO_REQUEUE;
 
                if (pgpath)
                        fail_path(pgpath);
 
                if (atomic_read(&m->nr_valid_paths) == 0 &&
-                   !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))
-                       error = dm_report_EIO(m);
+                   !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
+                       if (error == -EIO)
+                               error = dm_report_EIO(m);
+                       /* complete with the original error */
+                       r = DM_ENDIO_DONE;
+               }
        }
 
        if (pgpath) {
@@ -1501,7 +1506,7 @@ static int multipath_end_io(struct dm_target *ti, struct request *clone,
                        ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
        }
 
-       return error;
+       return r;
 }
 
 static int do_end_io_bio(struct multipath *m, struct bio *clone,

diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index d445b712970b268293aa4a34cbbbb6ad3549131d..920e854caba9849ceeb4bd1bcb6c6a8c6b28c067 100644 (file)
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -287,7 +287,7 @@ static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_
 
 static void dm_done(struct request *clone, int error, bool mapped)
 {
-       int r = error;
+       int r = DM_ENDIO_DONE;
        struct dm_rq_target_io *tio = clone->end_io_data;
        dm_request_endio_fn rq_end_io = NULL;
 
@@ -298,7 +298,7 @@ static void dm_done(struct request *clone, int error, bool mapped)
                        r = rq_end_io(tio->ti, clone, error, &tio->info);
        }
 
-       if (unlikely(r == -EREMOTEIO)) {
+       if (unlikely(error == -EREMOTEIO)) {
                if (req_op(clone) == REQ_OP_WRITE_SAME &&
                    !clone->q->limits.max_write_same_sectors)
                        disable_write_same(tio->md);
@@ -307,16 +307,19 @@ static void dm_done(struct request *clone, int error, bool mapped)
                        disable_write_zeroes(tio->md);
        }
 
-       if (r <= 0)
+       switch (r) {
+       case DM_ENDIO_DONE:
                /* The target wants to complete the I/O */
-               dm_end_request(clone, r);
-       else if (r == DM_ENDIO_INCOMPLETE)
+               dm_end_request(clone, error);
+               break;
+       case DM_ENDIO_INCOMPLETE:
                /* The target will handle the I/O */
                return;
-       else if (r == DM_ENDIO_REQUEUE)
+       case DM_ENDIO_REQUEUE:
                /* The target wants to requeue the I/O */
                dm_requeue_original_request(tio, false);
-       else {
+               break;
+       default:
                DMWARN("unimplemented target endio return value: %d", r);
                BUG();
        }

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 925b63cdef527bf055a87b9c3c53bb1e28f26568..5a02fc0ff311d6d02a558f48fe1475c8246adeea 100644 (file)
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -593,6 +593,7 @@ extern struct ratelimit_state dm_ratelimit_state;
 /*
  * Definitions of return values from target end_io function.
  */
+#define DM_ENDIO_DONE          0
 #define DM_ENDIO_INCOMPLETE    1
 #define DM_ENDIO_REQUEUE       2