block: Introduce new bio_split()

The new bio_split() can split arbitrary bios - it's not restricted to
single page bios, like the old bio_split() (previously renamed to
bio_pair_split()). It also has different semantics - it doesn't allocate
a struct bio_pair, leaving it up to the caller to handle completions.

Then convert the existing bio_pair_split() users to the new bio_split()
- and also nvme, which was open coding bio splitting.

(We have to take that BUG_ON() out of bio_integrity_trim() because this
bio_split() needs to use it, and there's no reason it has to be used on
bios marked as cloned; BIO_CLONED doesn't seem to have clearly
documented semantics anyways.)

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Neil Brown <neilb@suse.de>

1 files changed, 74 insertions, 62 deletions

diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 28789b82ae7d..3dda09a5ec41 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2338,75 +2338,29 @@ static void pkt_end_io_read_cloned(struct bio *bio, int err)
         pkt_bio_finished(pd);
 }
 
-static void pkt_make_request(struct request_queue *q, struct bio *bio)
+static void pkt_make_request_read(struct pktcdvd_device *pd, struct bio *bio)
 {
-        struct pktcdvd_device *pd;
-        char b[BDEVNAME_SIZE];
+        struct bio *cloned_bio = bio_clone(bio, GFP_NOIO);
+        struct packet_stacked_data *psd = mempool_alloc(psd_pool, GFP_NOIO);
+
+        psd->pd = pd;
+        psd->bio = bio;
+        cloned_bio->bi_bdev = pd->bdev;
+        cloned_bio->bi_private = psd;
+        cloned_bio->bi_end_io = pkt_end_io_read_cloned;
+        pd->stats.secs_r += bio_sectors(bio);
+        pkt_queue_bio(pd, cloned_bio);
+}
+
+static void pkt_make_request_write(struct request_queue *q, struct bio *bio)
+{
+        struct pktcdvd_device *pd = q->queuedata;
         sector_t zone;
         struct packet_data *pkt;
         int was_empty, blocked_bio;
         struct pkt_rb_node *node;
 
-        pd = q->queuedata;
-        if (!pd) {
-                pr_err("%s incorrect request queue\n",
-                       bdevname(bio->bi_bdev, b));
-                goto end_io;
-        }
-
-        /*
-         * Clone READ bios so we can have our own bi_end_io callback.
-         */
-        if (bio_data_dir(bio) == READ) {
-                struct bio *cloned_bio = bio_clone(bio, GFP_NOIO);
-                struct packet_stacked_data *psd = mempool_alloc(psd_pool, GFP_NOIO);
-
-                psd->pd = pd;
-                psd->bio = bio;
-                cloned_bio->bi_bdev = pd->bdev;
-                cloned_bio->bi_private = psd;
-                cloned_bio->bi_end_io = pkt_end_io_read_cloned;
-                pd->stats.secs_r += bio_sectors(bio);
-                pkt_queue_bio(pd, cloned_bio);
-                return;
-        }
-
-        if (!test_bit(PACKET_WRITABLE, &pd->flags)) {
-                pkt_notice(pd, "WRITE for ro device (%llu)\n",
-                           (unsigned long long)bio->bi_iter.bi_sector);
-                goto end_io;
-        }
-
-        if (!bio->bi_iter.bi_size || (bio->bi_iter.bi_size % CD_FRAMESIZE)) {
-                pkt_err(pd, "wrong bio size\n");
-                goto end_io;
-        }
-
-        blk_queue_bounce(q, &bio);
-
         zone = get_zone(bio->bi_iter.bi_sector, pd);
-        pkt_dbg(2, pd, "start = %6llx stop = %6llx\n",
-                (unsigned long long)bio->bi_iter.bi_sector,
-                (unsigned long long)bio_end_sector(bio));
-
-        /* Check if we have to split the bio */
-        {
-                struct bio_pair *bp;
-                sector_t last_zone;
-                int first_sectors;
-
-                last_zone = get_zone(bio_end_sector(bio) - 1, pd);
-                if (last_zone != zone) {
-                        BUG_ON(last_zone != zone + pd->settings.size);
-                        first_sectors = last_zone - bio->bi_iter.bi_sector;
-                        bp = bio_pair_split(bio, first_sectors);
-                        BUG_ON(!bp);
-                        pkt_make_request(q, &bp->bio1);
-                        pkt_make_request(q, &bp->bio2);
-                        bio_pair_release(bp);
-                        return;
-                }
-        }
 
         /*
          * If we find a matching packet in state WAITING or READ_WAIT, we can
@@ -2480,6 +2434,64 @@ static void pkt_make_request(struct request_queue *q, struct bio *bio)
                  */
                 wake_up(&pd->wqueue);
         }
+}
+
+static void pkt_make_request(struct request_queue *q, struct bio *bio)
+{
+        struct pktcdvd_device *pd;
+        char b[BDEVNAME_SIZE];
+        struct bio *split;
+
+        pd = q->queuedata;
+        if (!pd) {
+                pr_err("%s incorrect request queue\n",
+                       bdevname(bio->bi_bdev, b));
+                goto end_io;
+        }
+
+        pkt_dbg(2, pd, "start = %6llx stop = %6llx\n",
+                (unsigned long long)bio->bi_iter.bi_sector,
+                (unsigned long long)bio_end_sector(bio));
+
+        /*
+         * Clone READ bios so we can have our own bi_end_io callback.
+         */
+        if (bio_data_dir(bio) == READ) {
+                pkt_make_request_read(pd, bio);
+                return;
+        }
+
+        if (!test_bit(PACKET_WRITABLE, &pd->flags)) {
+                pkt_notice(pd, "WRITE for ro device (%llu)\n",
+                           (unsigned long long)bio->bi_iter.bi_sector);
+                goto end_io;
+        }
+
+        if (!bio->bi_iter.bi_size || (bio->bi_iter.bi_size % CD_FRAMESIZE)) {
+                pkt_err(pd, "wrong bio size\n");
+                goto end_io;
+        }
+
+        blk_queue_bounce(q, &bio);
+
+        do {
+                sector_t zone = get_zone(bio->bi_iter.bi_sector, pd);
+                sector_t last_zone = get_zone(bio_end_sector(bio) - 1, pd);
+
+                if (last_zone != zone) {
+                        BUG_ON(last_zone != zone + pd->settings.size);
+
+                        split = bio_split(bio, last_zone -
+                                          bio->bi_iter.bi_sector,
+                                          GFP_NOIO, fs_bio_set);
+                        bio_chain(split, bio);
+                } else {
+                        split = bio;
+                }
+
+                pkt_make_request_write(q, split);
+        } while (split != bio);
+
         return;
 end_io:
         bio_io_error(bio);