In preparation for moving some drivers out from under the host_lock,
make cmd_serial_number an atomic.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 2aeb2e9..13a3bf0 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -631,14 +631,15 @@ void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
* @host: the scsi host
* @cmd: command to assign serial number to
*
- * Description: a serial number identifies a request for error recovery
- * and debugging purposes. Protected by the Host_Lock of host.
+ * A serial number identifies a request for error recovery and debugging
+ * purposes.
*/
void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
{
- cmd->serial_number = host->cmd_serial_number++;
+ again:
+ cmd->serial_number = atomic_inc_return(&host->cmd_serial_number);
if (cmd->serial_number == 0)
- cmd->serial_number = host->cmd_serial_number++;
+ goto again;
}
EXPORT_SYMBOL(scsi_cmd_get_serial);
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index e7e3858..69dfabb 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -621,11 +621,9 @@ struct Scsi_Host {
short unsigned int sg_prot_tablesize;
short unsigned int max_sectors;
unsigned long dma_boundary;
- /*
- * Used to assign serial numbers to the cmds.
- * Protected by the host lock.
- */
- unsigned long cmd_serial_number;
+
+ /* Used to assign serial numbers to the cmds. */
+ atomic_t cmd_serial_number;
unsigned active_mode:2;
unsigned unchecked_isa_dma:1;
--
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