target: move write_same to struct spc_ops

Add spc_ops->execute_write_same() caller for ->execute_cmd() setup,
and update IBLOCK backends to use it.

(nab: add export of spc_get_write_same_sectors symbol)
(roland: Carry forward: Fix range calculation in WRITE SAME emulation
         when num blocks == 0)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 863c962e5021..ee70cc9f6a64 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -327,6 +327,23 @@ static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
         return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
 }
 
+static int iblock_execute_write_same(struct se_cmd *cmd)
+{
+        struct iblock_dev *ibd = cmd->se_dev->dev_ptr;
+        int ret;
+
+        ret = blkdev_issue_discard(ibd->ibd_bd, cmd->t_task_lba,
+                                   spc_get_write_same_sectors(cmd), GFP_KERNEL,
+                                   0);
+        if (ret < 0) {
+                pr_debug("blkdev_issue_discard() failed for WRITE_SAME\n");
+                return ret;
+        }
+
+        target_complete_cmd(cmd, GOOD);
+        return 0;
+}
+
 enum {
         Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 };
@@ -669,6 +686,7 @@ static void iblock_bio_done(struct bio *bio, int err)
 static struct spc_ops iblock_spc_ops = {
         .execute_rw             = iblock_execute_rw,
         .execute_sync_cache     = iblock_execute_sync_cache,
+        .execute_write_same     = iblock_execute_write_same,
 };
 
 static int iblock_parse_cdb(struct se_cmd *cmd)