target: Allow Write Exclusive non-reservation holders to READ

commit 1ecc7586922662e3ca2f3f0c3f17fec8749fc621 upstream.

For PGR reservation of type Write Exclusive Access, allow all non
reservation holding I_T nexuses with active registrations to READ
from the device.

This addresses a bug where active registrations that attempted
to READ would result in an reservation conflict.

Signed-off-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index 8df0c932db59f54927a223713221ac44e49c81e1..7f85f4a6d73a9c24664ea9de7d5c907c0af85d3b 100644 (file)
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -518,6 +518,18 @@ static int core_scsi3_pr_seq_non_holder(
 
                        return 0;
                }
+       } else if (we && registered_nexus) {
+               /*
+                * Reads are allowed for Write Exclusive locks
+                * from all registrants.
+                */
+               if (cmd->data_direction == DMA_FROM_DEVICE) {
+                       pr_debug("Allowing READ CDB: 0x%02x for %s"
+                               " reservation\n", cdb[0],
+                               core_scsi3_pr_dump_type(pr_reg_type));
+
+                       return 0;
+               }
        }
        pr_debug("%s Conflict for %sregistered nexus %s CDB: 0x%2x"
                " for %s reservation\n", transport_dump_cmd_direction(cmd),