target: Fix SYNCHRONIZE_CACHE zero LBA + range breakage

This patch fixes a SYNCHRONIZE_CACHE CDB handling bug with IBLOCK/FILEIO
backends where transport_cmd_get_valid_sectors() was incorrectly rejecting
a zero LBA + range CDB from being processed, and returning CHECK_CONDITION.

This includes changing transport_cmd_get_valid_sectors() to return '0' on
success and '-EINVAL' on failure (this makes more sense than sectors),
and to only check transport_cmd_get_valid_sectors() when a non zero LBA +
range SYNCHRONIZE_CACHE operation has been receieved for the non passthrough
case.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 7 insertions, 7 deletions

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index d35c2cc779e9..d385c317a7a4 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -2853,12 +2853,10 @@ static int transport_cmd_get_valid_sectors(struct se_cmd *cmd)
                         " transport_dev_end_lba(): %llu\n",
                         cmd->t_task_lba, sectors,
                         transport_dev_end_lba(dev));
-                pr_err("  We should return CHECK_CONDITION"
-                       " but we don't yet\n");
-                return 0;
+                return -EINVAL;
         }
 
-        return sectors;
+        return 0;
 }
 
 static int target_check_write_same_discard(unsigned char *flags, struct se_device *dev)
@@ -3350,10 +3348,12 @@ static int transport_generic_cmd_sequencer(
                 cmd->se_cmd_flags |= SCF_EMULATE_CDB_ASYNC;
                 /*
                  * Check to ensure that LBA + Range does not exceed past end of
-                 * device.
+                 * device for IBLOCK and FILEIO ->do_sync_cache() backend calls
                  */
-                if (!transport_cmd_get_valid_sectors(cmd))
-                        goto out_invalid_cdb_field;
+                if ((cmd->t_task_lba != 0) || (sectors != 0)) {
+                        if (transport_cmd_get_valid_sectors(cmd) < 0)
+                                goto out_invalid_cdb_field;
+                }
                 break;
         case UNMAP:
                 size = get_unaligned_be16(&cdb[7]);