[PATCH] fix SCSI non-sector bio backed IO

This fixes the SCSI layer to handle non-sector-aligned requests from
SG_IO (and potentially anything else producing these requests) that
could stall the machine and cause all sorts of funnies depending on the
low level driver used.

drivers/scsi/scsi_lib.c

@@ -493,7 +493,7 @@ void scsi_run_host_queues(struct Scsi_Host *shost)
  *		at some point during this call.
  */
 static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate,
-					  int sectors, int requeue)
+					  int bytes, int requeue)
 {
 	request_queue_t *q = cmd->device->request_queue;
 	struct request *req = cmd->request;
@@ -503,12 +503,15 @@ static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate,
 	 * If there are blocks left over at the end, set up the command
 	 * to queue the remainder of them.
 	 */
-	if (end_that_request_first(req, uptodate, sectors)) {
-		int leftover = req->hard_nr_sectors - sectors;
+	if (end_that_request_chunk(req, uptodate, bytes)) {
+		int leftover = (req->hard_nr_sectors << 9) - bytes;
+
+		if (blk_pc_request(req))
+			leftover = req->data_len - bytes;
 
 		/* kill remainder if no retrys */
 		if (!uptodate && blk_noretry_request(req))
-			end_that_request_first(req, 0, leftover);
+			end_that_request_chunk(req, 0, leftover);
 		else {
 			if (requeue)
 				/*
@@ -649,11 +652,11 @@ static void scsi_release_buffers(struct scsi_cmnd *cmd)
  *		b) We can just use scsi_requeue_command() here.  This would
  *		   be used if we just wanted to retry, for example.
  */
-void scsi_io_completion(struct scsi_cmnd *cmd, int good_sectors,
-			int block_sectors)
+void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes,
+			unsigned int block_bytes)
 {
 	int result = cmd->result;
-	int this_count = cmd->bufflen >> 9;
+	int this_count = cmd->bufflen;
 	request_queue_t *q = cmd->device->request_queue;
 	struct request *req = cmd->request;
 	int clear_errors = 1;
@@ -705,9 +708,9 @@ void scsi_io_completion(struct scsi_cmnd *cmd, int good_sectors,
 	 * Next deal with any sectors which we were able to correctly
 	 * handle.
 	 */
-	if (good_sectors >= 0) {
-		SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d sectors done.\n",
-					      req->nr_sectors, good_sectors));
+	if (good_bytes >= 0) {
+		SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n",
+					      req->nr_sectors, good_bytes));
 		SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg));
 
 		if (clear_errors)
@@ -717,13 +720,13 @@ void scsi_io_completion(struct scsi_cmnd *cmd, int good_sectors,
 		 * they will have been finished off by the first command.
 		 * If not, then we have a multi-buffer command.
 		 *
-		 * If block_sectors != 0, it means we had a medium error
+		 * If block_bytes != 0, it means we had a medium error
 		 * of some sort, and that we want to mark some number of
 		 * sectors as not uptodate.  Thus we want to inhibit
 		 * requeueing right here - we will requeue down below
 		 * when we handle the bad sectors.
 		 */
-		cmd = scsi_end_request(cmd, 1, good_sectors, result == 0);
+		cmd = scsi_end_request(cmd, 1, good_bytes, result == 0);
 
 		/*
 		 * If the command completed without error, then either finish off the
@@ -808,7 +811,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, int good_sectors,
 			       (int) cmd->device->id, (int) cmd->device->lun);
 			print_command(cmd->data_cmnd);
 			print_sense("", cmd);
-			cmd = scsi_end_request(cmd, 0, block_sectors, 1);
+			cmd = scsi_end_request(cmd, 0, block_bytes, 1);
 			return;
 		default:
 			break;
@@ -837,8 +840,10 @@ void scsi_io_completion(struct scsi_cmnd *cmd, int good_sectors,
 		 * We sometimes get this cruft in the event that a medium error
 		 * isn't properly reported.
 		 */
-		cmd = scsi_end_request(cmd, 0, req->current_nr_sectors, 1);
-		return;
+		block_bytes = req->hard_cur_sectors << 9;
+		if (!block_bytes)
+			block_bytes = req->data_len;
+		cmd = scsi_end_request(cmd, 0, block_bytes, 1);
 	}
 }
 

drivers/scsi/sd.c

@@ -661,8 +661,8 @@ static struct block_device_operations sd_fops = {
 static void sd_rw_intr(struct scsi_cmnd * SCpnt)
 {
 	int result = SCpnt->result;
-	int this_count = SCpnt->bufflen >> 9;
-	int good_sectors = (result == 0 ? this_count : 0);
+	int this_count = SCpnt->bufflen;
+	int good_bytes = (result == 0 ? this_count : 0);
 	sector_t block_sectors = 1;
 	sector_t error_sector;
 #ifdef CONFIG_SCSI_LOGGING
@@ -688,6 +688,8 @@ static void sd_rw_intr(struct scsi_cmnd * SCpnt)
 		case MEDIUM_ERROR:
 			if (!(SCpnt->sense_buffer[0] & 0x80))
 				break;
+			if (!blk_fs_request(SCpnt->request))
+				break;
 			error_sector = (SCpnt->sense_buffer[3] << 24) |
 			(SCpnt->sense_buffer[4] << 16) |
 			(SCpnt->sense_buffer[5] << 8) |
@@ -718,9 +720,9 @@ static void sd_rw_intr(struct scsi_cmnd * SCpnt)
 			}
 
 			error_sector &= ~(block_sectors - 1);
-			good_sectors = error_sector - SCpnt->request->sector;
-			if (good_sectors < 0 || good_sectors >= this_count)
-				good_sectors = 0;
+			good_bytes = (error_sector - SCpnt->request->sector) << 9;
+			if (good_bytes < 0 || good_bytes >= this_count)
+				good_bytes = 0;
 			break;
 
 		case RECOVERED_ERROR:
@@ -732,7 +734,7 @@ static void sd_rw_intr(struct scsi_cmnd * SCpnt)
 			print_sense("sd", SCpnt);
 			SCpnt->result = 0;
 			SCpnt->sense_buffer[0] = 0x0;
-			good_sectors = this_count;
+			good_bytes = this_count;
 			break;
 
 		case ILLEGAL_REQUEST:
@@ -755,7 +757,7 @@ static void sd_rw_intr(struct scsi_cmnd * SCpnt)
 	 * how many actual sectors finished, and how many sectors we need
 	 * to say have failed.
 	 */
-	scsi_io_completion(SCpnt, good_sectors, block_sectors);
+	scsi_io_completion(SCpnt, good_bytes, block_sectors << 9);
 }
 
 static int media_not_present(struct scsi_disk *sdkp, struct scsi_request *srp)

drivers/scsi/sr.c

@@ -179,14 +179,14 @@ static inline struct scsi_cd *scsi_cd(struct gendisk *disk)
 static void rw_intr(struct scsi_cmnd * SCpnt)
 {
 	int result = SCpnt->result;
-	int this_count = SCpnt->bufflen >> 9;
-	int good_sectors = (result == 0 ? this_count : 0);
+	int this_count = SCpnt->bufflen;
+	int good_bytes = (result == 0 ? this_count : 0);
 	int block_sectors = 0;
 	long error_sector;
 	struct scsi_cd *cd = scsi_cd(SCpnt->request->rq_disk);
 
 #ifdef DEBUG
-	printk("sr.c done: %x %p\n", result, SCpnt->request->bh->b_data);
+	printk("sr.c done: %x\n", result);
 #endif
 
 	/*
@@ -203,6 +203,8 @@ static void rw_intr(struct scsi_cmnd * SCpnt)
 		case ILLEGAL_REQUEST:
 			if (!(SCpnt->sense_buffer[0] & 0x90))
 				break;
+			if (!blk_fs_request(SCpnt->request))
+				break;
 			error_sector = (SCpnt->sense_buffer[3] << 24) |
 				(SCpnt->sense_buffer[4] << 16) |
 				(SCpnt->sense_buffer[5] << 8) |
@@ -215,9 +217,9 @@ static void rw_intr(struct scsi_cmnd * SCpnt)
 			if (cd->device->sector_size == 2048)
 				error_sector <<= 2;
 			error_sector &= ~(block_sectors - 1);
-			good_sectors = error_sector - SCpnt->request->sector;
-			if (good_sectors < 0 || good_sectors >= this_count)
-				good_sectors = 0;
+			good_bytes = (error_sector - SCpnt->request->sector) << 9;
+			if (good_bytes < 0 || good_bytes >= this_count)
+				good_bytes = 0;
 			/*
 			 * The SCSI specification allows for the value
 			 * returned by READ CAPACITY to be up to 75 2K
@@ -241,7 +243,7 @@ static void rw_intr(struct scsi_cmnd * SCpnt)
 			print_sense("sr", SCpnt);
 			SCpnt->result = 0;
 			SCpnt->sense_buffer[0] = 0x0;
-			good_sectors = this_count;
+			good_bytes = this_count;
 			break;
 
 		default:
@@ -254,7 +256,7 @@ static void rw_intr(struct scsi_cmnd * SCpnt)
 	 * how many actual sectors finished, and how many sectors we need
 	 * to say have failed.
 	 */
-	scsi_io_completion(SCpnt, good_sectors, block_sectors);
+	scsi_io_completion(SCpnt, good_bytes, block_sectors << 9);
 }
 
 static int sr_init_command(struct scsi_cmnd * SCpnt)

drivers/scsi/st.c

@@ -4005,7 +4005,7 @@ static int st_remove(struct device *dev)
 
 static void st_intr(struct scsi_cmnd *SCpnt)
 {
-	scsi_io_completion(SCpnt, (SCpnt->result ? 0: SCpnt->bufflen >> 9), 1);
+	scsi_io_completion(SCpnt, (SCpnt->result ? 0: SCpnt->bufflen), 1);
 }
 
 /*

include/scsi/scsi_cmnd.h

@@ -158,6 +158,6 @@ struct scsi_cmnd {
 
 extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, int);
 extern void scsi_put_command(struct scsi_cmnd *);
-extern void scsi_io_completion(struct scsi_cmnd *, int, int);
+extern void scsi_io_completion(struct scsi_cmnd *, unsigned int, unsigned int);
 
 #endif /* _SCSI_SCSI_CMND_H */