[PATCH] USB Storage: remove dependency on SCSI-provided serial/tag number

This patch started life as as531 from Alan Stern.  It has been rediffed
against the latest tree.

The SCSI people have deprecated the use of scsi_cmnd.serial_number for
anything other than printk.  Worse than that, the SCSI core doesn't
always increment the number (when the error handler is running, for
example).  So this patch creates a locally-stored value for use in
bulk-only tags.  The net result is a simplification, since we no longer
have to save & restore the serial_number value while autosensing.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 3 insertions, 8 deletions

diff --git a/drivers/usb/storage/transport.c b/drivers/usb/storage/transport.c
index e6b1c6cf07f2..e42875152c34 100644
--- a/drivers/usb/storage/transport.c
+++ b/drivers/usb/storage/transport.c
@@ -611,7 +611,6 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
                 unsigned char old_sc_data_direction;
                 unsigned char old_cmd_len;
                 unsigned char old_cmnd[MAX_COMMAND_SIZE];
-                unsigned long old_serial_number;
                 int old_resid;
 
                 US_DEBUGP("Issuing auto-REQUEST_SENSE\n");
@@ -648,10 +647,6 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
                 old_sg = srb->use_sg;
                 srb->use_sg = 0;
 
-                /* change the serial number -- toggle the high bit*/
-                old_serial_number = srb->serial_number;
-                srb->serial_number ^= 0x80000000;
-
                 /* issue the auto-sense command */
                 old_resid = srb->resid;
                 srb->resid = 0;
@@ -662,7 +657,6 @@ void usb_stor_invoke_transport(struct scsi_cmnd *srb, struct us_data *us)
                 srb->request_buffer = old_request_buffer;
                 srb->request_bufflen = old_request_bufflen;
                 srb->use_sg = old_sg;
-                srb->serial_number = old_serial_number;
                 srb->sc_data_direction = old_sc_data_direction;
                 srb->cmd_len = old_cmd_len;
                 memcpy(srb->cmnd, old_cmnd, MAX_COMMAND_SIZE);
@@ -985,7 +979,7 @@ int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
         bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
         bcb->DataTransferLength = cpu_to_le32(transfer_length);
         bcb->Flags = srb->sc_data_direction == DMA_FROM_DEVICE ? 1 << 7 : 0;
-        bcb->Tag = srb->serial_number;
+        bcb->Tag = ++us->tag;
         bcb->Lun = srb->device->lun;
         if (us->flags & US_FL_SCM_MULT_TARG)
                 bcb->Lun |= srb->device->id << 4;
@@ -1074,7 +1068,7 @@ int usb_stor_Bulk_transport(struct scsi_cmnd *srb, struct us_data *us)
         US_DEBUGP("Bulk Status S 0x%x T 0x%x R %u Stat 0x%x\n",
                         le32_to_cpu(bcs->Signature), bcs->Tag, 
                         residue, bcs->Status);
-        if (bcs->Tag != srb->serial_number || bcs->Status > US_BULK_STAT_PHASE) {
+        if (bcs->Tag != us->tag || bcs->Status > US_BULK_STAT_PHASE) {
                 US_DEBUGP("Bulk logical error\n");
                 return USB_STOR_TRANSPORT_ERROR;
         }
diff --git a/drivers/usb/storage/usb.h b/drivers/usb/storage/usb.h
index 625b7aa98074..a195adae57b6 100644
--- a/drivers/usb/storage/usb.h
+++ b/drivers/usb/storage/usb.h
@@ -158,6 +158,7 @@ struct us_data {
 
         /* SCSI interfaces */
         struct scsi_cmnd        *srb;            /* current srb         */
+        unsigned int            tag;             /* current dCBWTag     */
 
         /* thread information */
         int                     pid;             /* control thread       */