Skip to contentSkip to conversation

make SCSI error handler preserve data transfer residual

PATCH New Tony Battersby 1 participant 1 message Nov 1, 2004 SCSI

lore
Share & tools
lore

Tony Battersby

author
#0 lore raw

PATCH 1/1 make SCSI error handler preserve data transfer residual

This is a resend of http://marc.theaimsgroup.com/?l=linux-scsi&m=108445913200046&w=2.

When a SCSI command fails, the error handler in 2.4.x may send a command such as request sense which clobbers the data transfer residual value of the original command. This patch makes the error handler
save and restore the data transfer residual so that the value passed back to the upper level reflects the residual of the original command rather than the error handler's internal command. This makes a difference for userspace applications that use the /dev/sg* interface that require a correct data transfer residual count even for commands that went through error handling.

Please apply.

drivers/scsi/scsi_error.c +6 -0
@@ -410,6 +410,7 @@
 	{REQUEST_SENSE, 0, 0, 0, 255, 0};
 	unsigned char scsi_result0[256], *scsi_result = NULL;
 	int saved_result;
+	int saved_resid;
 
 	ASSERT_LOCK(&io_request_lock, 0);
 

@@ -436,6 +437,7 @@
 	memset((void *) scsi_result, 0, 256);
 
 	saved_result = SCpnt->result;
+	saved_resid = SCpnt->resid;
 	SCpnt->request_buffer = scsi_result;
 	SCpnt->request_bufflen = 256;
 	SCpnt->use_sg = 0;

@@ -461,6 +463,7 @@
 	memcpy((void *) SCpnt->cmnd, (void *) SCpnt->data_cmnd,
 	       sizeof(SCpnt->data_cmnd));
 	SCpnt->result = saved_result;
+	SCpnt->resid = saved_resid;
 	SCpnt->request_buffer = SCpnt->buffer;
 	SCpnt->request_bufflen = SCpnt->bufflen;
 	SCpnt->use_sg = SCpnt->old_use_sg;

@@ -484,6 +487,7 @@
 {
 	static unsigned char tur_command[6] =
 	{TEST_UNIT_READY, 0, 0, 0, 0, 0};
+	int saved_resid;
 
 	memcpy((void *) SCpnt->cmnd, (void *) tur_command,
 	       sizeof(tur_command));

@@ -497,6 +501,7 @@
 	 */
 	memset((void *) SCpnt->sense_buffer, 0, sizeof(SCpnt->sense_buffer));
 
+	saved_resid = SCpnt->resid;
 	SCpnt->request_buffer = NULL;
 	SCpnt->request_bufflen = 0;
 	SCpnt->use_sg = 0;

@@ -512,6 +517,7 @@
 	 */
 	memcpy((void *) SCpnt->cmnd, (void *) SCpnt->data_cmnd,
 	       sizeof(SCpnt->data_cmnd));
+	SCpnt->resid = saved_resid;
 	SCpnt->request_buffer = SCpnt->buffer;
 	SCpnt->request_bufflen = SCpnt->bufflen;
 	SCpnt->use_sg = SCpnt->old_use_sg;

Anthony J. Battersby
Cybernetics