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>

2 files changed, 36 insertions, 34 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)
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 377c5105e270..146ca372489b 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -156,24 +156,9 @@ err:
         return ret;
 }
 
-/*
- * Used for TCM/IBLOCK and TCM/FILEIO for block/blk-lib.c level discard support.
- * Note this is not used for TCM/pSCSI passthrough
- */
-static int sbc_emulate_write_same(struct se_cmd *cmd)
+int spc_get_write_same_sectors(struct se_cmd *cmd)
 {
-        struct se_device *dev = cmd->se_dev;
-        sector_t range;
-        sector_t lba = cmd->t_task_lba;
         u32 num_blocks;
-        int ret;
-
-        if (!dev->transport->do_discard) {
-                pr_err("WRITE_SAME emulation not supported"
-                                " for: %s\n", dev->transport->name);
-                cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
-                return -ENOSYS;
-        }
 
         if (cmd->t_task_cdb[0] == WRITE_SAME)
                 num_blocks = get_unaligned_be16(&cmd->t_task_cdb[7]);
@@ -186,23 +171,13 @@ static int sbc_emulate_write_same(struct se_cmd *cmd)
          * Use the explicit range when non zero is supplied, otherwise calculate
          * the remaining range based on ->get_blocks() - starting LBA.
          */
-        if (num_blocks != 0)
-                range = num_blocks;
-        else
-                range = (dev->transport->get_blocks(dev) - lba) + 1;
+        if (num_blocks)
+                return num_blocks;
 
-        pr_debug("WRITE_SAME UNMAP: LBA: %llu Range: %llu\n",
-                 (unsigned long long)lba, (unsigned long long)range);
-
-        ret = dev->transport->do_discard(dev, lba, range);
-        if (ret < 0) {
-                pr_debug("blkdev_issue_discard() failed for WRITE_SAME\n");
-                return ret;
-        }
-
-        target_complete_cmd(cmd, GOOD);
-        return 0;
+        return cmd->se_dev->transport->get_blocks(cmd->se_dev) -
+                cmd->t_task_lba + 1;
 }
+EXPORT_SYMBOL(spc_get_write_same_sectors);
 
 static int sbc_emulate_verify(struct se_cmd *cmd)
 {
@@ -488,6 +463,9 @@ int sbc_parse_cdb(struct se_cmd *cmd, struct spc_ops *ops)
                                 cmd->se_cmd_flags |= SCF_FUA;
                         break;
                 case WRITE_SAME_32:
+                        if (!ops->execute_write_same)
+                                goto out_unsupported_cdb;
+
                         sectors = transport_get_sectors_32(cdb);
                         if (!sectors) {
                                 pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
@@ -500,7 +478,7 @@ int sbc_parse_cdb(struct se_cmd *cmd, struct spc_ops *ops)
 
                         if (sbc_write_same_supported(dev, &cdb[10]) < 0)
                                 goto out_unsupported_cdb;
-                        cmd->execute_cmd = sbc_emulate_write_same;
+                        cmd->execute_cmd = ops->execute_write_same;
                         break;
                 default:
                         pr_err("VARIABLE_LENGTH_CMD service action"
@@ -559,6 +537,9 @@ int sbc_parse_cdb(struct se_cmd *cmd, struct spc_ops *ops)
                 cmd->execute_cmd = sbc_emulate_unmap;
                 break;
         case WRITE_SAME_16:
+                if (!ops->execute_write_same)
+                        goto out_unsupported_cdb;
+
                 sectors = transport_get_sectors_16(cdb);
                 if (!sectors) {
                         pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
@@ -570,9 +551,12 @@ int sbc_parse_cdb(struct se_cmd *cmd, struct spc_ops *ops)
 
                 if (sbc_write_same_supported(dev, &cdb[1]) < 0)
                         goto out_unsupported_cdb;
-                cmd->execute_cmd = sbc_emulate_write_same;
+                cmd->execute_cmd = ops->execute_write_same;
                 break;
         case WRITE_SAME:
+                if (!ops->execute_write_same)
+                        goto out_unsupported_cdb;
+
                 sectors = transport_get_sectors_10(cdb);
                 if (!sectors) {
                         pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
@@ -588,7 +572,7 @@ int sbc_parse_cdb(struct se_cmd *cmd, struct spc_ops *ops)
                  */
                 if (sbc_write_same_supported(dev, &cdb[1]) < 0)
                         goto out_unsupported_cdb;
-                cmd->execute_cmd = sbc_emulate_write_same;
+                cmd->execute_cmd = ops->execute_write_same;
                 break;
         case VERIFY:
                 size = 0;