target: Add return for se_cmd->transport_complete_callback

This patch adds a sense_reason_t return to ->transport_complete_callback(),
and updates target_complete_ok_work() to invoke the call if necessary to
transport_send_check_condition_and_sense() during the failure case.

Also update xdreadwrite_callback() to use this return value.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

3 files changed, 26 insertions, 9 deletions

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index 8a462773d0c8..be5234abb76c 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -280,13 +280,13 @@ sbc_setup_write_same(struct se_cmd *cmd, unsigned char *flags, struct sbc_ops *o
         return 0;
 }
 
-static void xdreadwrite_callback(struct se_cmd *cmd)
+static sense_reason_t xdreadwrite_callback(struct se_cmd *cmd)
 {
         unsigned char *buf, *addr;
         struct scatterlist *sg;
         unsigned int offset;
-        int i;
-        int count;
+        sense_reason_t ret = TCM_NO_SENSE;
+        int i, count;
         /*
          * From sbc3r22.pdf section 5.48 XDWRITEREAD (10) command
          *
@@ -301,7 +301,7 @@ static void xdreadwrite_callback(struct se_cmd *cmd)
         buf = kmalloc(cmd->data_length, GFP_KERNEL);
         if (!buf) {
                 pr_err("Unable to allocate xor_callback buf\n");
-                return;
+                return TCM_OUT_OF_RESOURCES;
         }
         /*
          * Copy the scatterlist WRITE buffer located at cmd->t_data_sg
@@ -320,8 +320,10 @@ static void xdreadwrite_callback(struct se_cmd *cmd)
         offset = 0;
         for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, count) {
                 addr = kmap_atomic(sg_page(sg));
-                if (!addr)
+                if (!addr) {
+                        ret = TCM_OUT_OF_RESOURCES;
                         goto out;
+                }
 
                 for (i = 0; i < sg->length; i++)
                         *(addr + sg->offset + i) ^= *(buf + offset + i);
@@ -332,6 +334,7 @@ static void xdreadwrite_callback(struct se_cmd *cmd)
 
 out:
         kfree(buf);
+        return ret;
 }
 
 sense_reason_t
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 98ec7110873b..53d1d756f7f5 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -1904,10 +1904,24 @@ static void target_complete_ok_work(struct work_struct *work)
         }
         /*
          * Check for a callback, used by amongst other things
-         * XDWRITE_READ_10 emulation.
+         * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
          */
-        if (cmd->transport_complete_callback)
-                cmd->transport_complete_callback(cmd);
+        if (cmd->transport_complete_callback) {
+                sense_reason_t rc;
+
+                rc = cmd->transport_complete_callback(cmd);
+                if (!rc)
+                        return;
+
+                ret = transport_send_check_condition_and_sense(cmd,
+                                        rc, 0);
+                if (ret == -EAGAIN || ret == -ENOMEM)
+                        goto queue_full;
+
+                transport_lun_remove_cmd(cmd);
+                transport_cmd_check_stop_to_fabric(cmd);
+                return;
+        }
 
         switch (cmd->data_direction) {
         case DMA_FROM_DEVICE:
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index bd55acd43005..6892b3332ebb 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -447,7 +447,7 @@ struct se_cmd {
         struct kref             cmd_kref;
         struct target_core_fabric_ops *se_tfo;
         sense_reason_t          (*execute_cmd)(struct se_cmd *);
-        void (*transport_complete_callback)(struct se_cmd *);
+        sense_reason_t (*transport_complete_callback)(struct se_cmd *);
 
         unsigned char           *t_task_cdb;
         unsigned char           __t_task_cdb[TCM_MAX_COMMAND_SIZE];