dm writecache: further writecache_map() cleanup

Factor out writecache_map_flush() and writecache_map_discard() from
writecache_map(). Also eliminate the various goto labels in
writecache_map().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 2a920e9..64d7a79 100644 (file)
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -1447,31 +1447,52 @@ bio_copy:
        return WC_MAP_SUBMIT;
 }
 
+static enum wc_map_op writecache_map_flush(struct dm_writecache *wc, struct bio *bio)
+{
+       if (writecache_has_error(wc))
+               return WC_MAP_ERROR;
+
+       if (WC_MODE_PMEM(wc)) {
+               writecache_flush(wc);
+               if (writecache_has_error(wc))
+                       return WC_MAP_ERROR;
+               else if (unlikely(wc->cleaner) || unlikely(wc->metadata_only))
+                       return WC_MAP_REMAP_ORIGIN;
+               return WC_MAP_SUBMIT;
+       }
+       /* SSD: */
+       if (dm_bio_get_target_bio_nr(bio))
+               return WC_MAP_REMAP_ORIGIN;
+       writecache_offload_bio(wc, bio);
+       return WC_MAP_RETURN;
+}
+
+static enum wc_map_op writecache_map_discard(struct dm_writecache *wc, struct bio *bio)
+{
+       if (writecache_has_error(wc))
+               return WC_MAP_ERROR;
+
+       if (WC_MODE_PMEM(wc)) {
+               writecache_discard(wc, bio->bi_iter.bi_sector, bio_end_sector(bio));
+               return WC_MAP_REMAP_ORIGIN;
+       }
+       /* SSD: */
+       writecache_offload_bio(wc, bio);
+       return WC_MAP_RETURN;
+}
+
 static int writecache_map(struct dm_target *ti, struct bio *bio)
 {
        struct dm_writecache *wc = ti->private;
-       enum wc_map_op map_op = WC_MAP_ERROR;
+       enum wc_map_op map_op;
 
        bio->bi_private = NULL;
 
        wc_lock(wc);
 
        if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
-               if (writecache_has_error(wc))
-                       goto unlock_error;
-               if (WC_MODE_PMEM(wc)) {
-                       writecache_flush(wc);
-                       if (writecache_has_error(wc))
-                               goto unlock_error;
-                       if (unlikely(wc->cleaner) || unlikely(wc->metadata_only))
-                               goto unlock_remap_origin;
-                       goto unlock_submit;
-               } else {
-                       if (dm_bio_get_target_bio_nr(bio))
-                               goto unlock_remap_origin;
-                       writecache_offload_bio(wc, bio);
-                       goto unlock_return;
-               }
+               map_op = writecache_map_flush(wc, bio);
+               goto done;
        }
 
        bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
@@ -1481,29 +1502,22 @@ static int writecache_map(struct dm_target *ti, struct bio *bio)
                DMERR("I/O is not aligned, sector %llu, size %u, block size %u",
                      (unsigned long long)bio->bi_iter.bi_sector,
                      bio->bi_iter.bi_size, wc->block_size);
-               goto unlock_error;
+               map_op = WC_MAP_ERROR;
+               goto done;
        }
 
        if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) {
-               if (writecache_has_error(wc))
-                       goto unlock_error;
-               if (WC_MODE_PMEM(wc)) {
-                       writecache_discard(wc, bio->bi_iter.bi_sector, bio_end_sector(bio));
-                       goto unlock_remap_origin;
-               } else {
-                       writecache_offload_bio(wc, bio);
-                       goto unlock_return;
-               }
+               map_op = writecache_map_discard(wc, bio);
+               goto done;
        }
 
        if (bio_data_dir(bio) == READ)
                map_op = writecache_map_read(wc, bio);
        else
                map_op = writecache_map_write(wc, bio);
-
+done:
        switch (map_op) {
        case WC_MAP_REMAP_ORIGIN:
-unlock_remap_origin:
                if (likely(wc->pause != 0)) {
                        if (bio_op(bio) == REQ_OP_WRITE) {
                                dm_iot_io_begin(&wc->iot, 1);
@@ -1515,7 +1529,6 @@ unlock_remap_origin:
                return DM_MAPIO_REMAPPED;
 
        case WC_MAP_REMAP:
-unlock_remap:
                /* make sure that writecache_end_io decrements bio_in_progress: */
                bio->bi_private = (void *)1;
                atomic_inc(&wc->bio_in_progress[bio_data_dir(bio)]);
@@ -1523,18 +1536,16 @@ unlock_remap:
                return DM_MAPIO_REMAPPED;
 
        case WC_MAP_SUBMIT:
-unlock_submit:
                wc_unlock(wc);
                bio_endio(bio);
                return DM_MAPIO_SUBMITTED;
 
        case WC_MAP_RETURN:
-unlock_return:
                wc_unlock(wc);
                return DM_MAPIO_SUBMITTED;
 
        case WC_MAP_ERROR:
-unlock_error:
+       default:
                wc_unlock(wc);
                bio_io_error(bio);
                return DM_MAPIO_SUBMITTED;