[PATCH] fix rq->flags use in ide-tape.c

Noticed by Stuart_Hayes@Dell.com:

I've noticed that, in the 2.6 (test 9) kernel, the "cmd" field (of type int)
in struct request has been removed, and it looks like all of the code in
ide-tape has just had a find & replace run on it to replace any instance of
rq.cmd or rq->cmd with rq.flags or rq->flags.

The values being put into "cmd" in 2.4 (now "flags", in 2.6) by ide-tape are
8-bit numbers, like 90, 91, etc... and the actual flags that are being used
in "flags" cover the low 23 bits.  So, not only do the flags get wiped out
when, say, ide-tape assigns, say, 90 to "flags", but also the 90 gets wiped
out when one of the flags is modified.

I noticed this, because ide-tape checks this value, and spews error codes
when it isn't correct--continuously--as soon as you load the module, because
ide-tape is calling ide_do_drive_cmd with an action of ide_preempt, which
causes ide_do_drive_cmd to set the REQ_PREEMPT flag, so "flags" isn't the
same when it gets back to idetape_do_request.

drivers/block/ll_rw_blk.c

@@ -780,6 +780,11 @@ static char *rq_flags[] = {
 	"REQ_PM_SUSPEND",
 	"REQ_PM_RESUME",
 	"REQ_PM_SHUTDOWN",
+	"REQ_IDETAPE_PC1",
+	"REQ_IDETAPE_PC2",
+	"REQ_IDETAPE_READ",
+	"REQ_IDETAPE_WRITE",
+	"REQ_IDETAPE_READ_BUFFER",
 };
 
 void blk_dump_rq_flags(struct request *rq, char *msg)

drivers/ide/ide-tape.c

@@ -1210,34 +1210,11 @@ typedef struct {
  *	In order to service a character device command, we add special
  *	requests to the tail of our block device request queue and wait
  *	for their completion.
- *
- */
-#define IDETAPE_FIRST_RQ		90
-
-/*
- * 	IDETAPE_PC_RQ is used to queue a packet command in the request queue.
  */
-#define IDETAPE_PC_RQ1			90
-#define IDETAPE_PC_RQ2			91
-
-/*
- *	IDETAPE_READ_RQ and IDETAPE_WRITE_RQ are used by our
- *	character device interface to request read/write operations from
- *	our block device interface.
- */
-#define IDETAPE_READ_RQ			92
-#define IDETAPE_WRITE_RQ		93
-#define IDETAPE_ABORTED_WRITE_RQ	94
-#define IDETAPE_ABORTED_READ_RQ		95
-#define IDETAPE_READ_BUFFER_RQ		96
-
-#define IDETAPE_LAST_RQ			96
-
-/*
- *	A macro which can be used to check if a we support a given
- *	request command.
- */
-#define IDETAPE_RQ_CMD(cmd) 		((cmd >= IDETAPE_FIRST_RQ) && (cmd <= IDETAPE_LAST_RQ))
+#define idetape_request(rq) \
+	((rq)->flags & (REQ_IDETAPE_PC1 | REQ_IDETAPE_PC2 | \
+			REQ_IDETAPE_READ | REQ_IDETAPE_WRITE | \
+			REQ_IDETAPE_READ_BUFFER))
 
 /*
  *	Error codes which are returned in rq->errors to the higher part
@@ -1891,7 +1868,7 @@ static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
 		tape->active_stage = NULL;
 		tape->active_data_request = NULL;
 		tape->nr_pending_stages--;
-		if (rq->flags == IDETAPE_WRITE_RQ) {
+		if (rq->flags & REQ_IDETAPE_WRITE) {
 #if ONSTREAM_DEBUG
 			if (tape->debug_level >= 2) {
 				if (tape->onstream) {
@@ -1937,7 +1914,7 @@ static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
 					}
 				}
 			}
-		} else if (rq->flags == IDETAPE_READ_RQ) {
+		} else if (rq->flags & REQ_IDETAPE_READ) {
 			if (error == IDETAPE_ERROR_EOD) {
 				set_bit(IDETAPE_PIPELINE_ERROR, &tape->flags);
 				idetape_abort_pipeline(drive, active_stage);
@@ -2016,9 +1993,9 @@ static void idetape_create_request_sense_cmd (idetape_pc_t *pc)
  */
 static void idetape_queue_pc_head (ide_drive_t *drive, idetape_pc_t *pc,struct request *rq)
 {
-	ide_init_drive_cmd(rq);
+	memset(rq, 0, sizeof(*rq));
+	rq->flags = REQ_IDETAPE_PC1;
 	rq->buffer = (char *) pc;
-	rq->flags = IDETAPE_PC_RQ1;
 	(void) ide_do_drive_cmd(drive, rq, ide_preempt);
 }
 
@@ -2711,7 +2688,7 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 					  struct request *rq, sector_t block)
 {
 	idetape_tape_t *tape = drive->driver_data;
-	idetape_pc_t *pc;
+	idetape_pc_t *pc = NULL;
 	struct request *postponed_rq = tape->postponed_rq;
 	atapi_status_t status;
 
@@ -2728,7 +2705,7 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 			rq->sector, rq->nr_sectors, rq->current_nr_sectors);
 #endif /* IDETAPE_DEBUG_LOG */
 
-	if (!IDETAPE_RQ_CMD(rq->flags)) {
+	if (!idetape_request(rq)) {
 		/*
 		 * We do not support buffer cache originated requests.
 		 */
@@ -2769,7 +2746,7 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 	 */
 	if (tape->onstream)
 		status.b.dsc = 1;
-	if (!drive->dsc_overlap && rq->flags != IDETAPE_PC_RQ2)
+	if (!drive->dsc_overlap && !(rq->flags & REQ_IDETAPE_PC2))
 		set_bit(IDETAPE_IGNORE_DSC, &tape->flags);
 
 	/*
@@ -2783,7 +2760,7 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 	if (tape->tape_still_time > 100 && tape->tape_still_time < 200)
 		tape->measure_insert_time = 1;
 	if (tape->req_buffer_fill &&
-	    (rq->flags == IDETAPE_WRITE_RQ || rq->flags == IDETAPE_READ_RQ)) {
+	    (rq->flags & (REQ_IDETAPE_WRITE | REQ_IDETAPE_READ))) {
 		tape->req_buffer_fill = 0;
 		tape->writes_since_buffer_fill = 0;
 		tape->reads_since_buffer_fill = 0;
@@ -2797,12 +2774,12 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 		tape->insert_speed = tape->insert_size / 1024 * HZ / (jiffies - tape->insert_time);
 	calculate_speeds(drive);
 	if (tape->onstream && tape->max_frames &&
-	    ((rq->flags == IDETAPE_WRITE_RQ &&
+	    (((rq->flags & REQ_IDETAPE_WRITE) &&
               ( tape->cur_frames == tape->max_frames ||
                 ( tape->speed_control && tape->cur_frames > 5 &&
                        (tape->insert_speed > tape->max_insert_speed ||
                         (0 /* tape->cur_frames > 30 && tape->tape_still_time > 200 */) ) ) ) ) ||
-	     (rq->flags == IDETAPE_READ_RQ &&
+	     ((rq->flags & REQ_IDETAPE_READ) &&
 	      ( tape->cur_frames == 0 ||
 		( tape->speed_control && (tape->cur_frames < tape->max_frames - 5) &&
 			tape->insert_speed > tape->max_insert_speed ) ) && rq->nr_sectors) ) ) {
@@ -2831,7 +2808,7 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 		} else if ((signed long) (jiffies - tape->dsc_timeout) > 0) {
 			printk(KERN_ERR "ide-tape: %s: DSC timeout\n",
 				tape->name);
-			if (rq->flags == IDETAPE_PC_RQ2) {
+			if (rq->flags & REQ_IDETAPE_PC2) {
 				idetape_media_access_finished(drive);
 				return ide_stopped;
 			} else {
@@ -2842,8 +2819,7 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 		idetape_postpone_request(drive);
 		return ide_stopped;
 	}
-	switch (rq->flags) {
-		case IDETAPE_READ_RQ:
+	if (rq->flags & REQ_IDETAPE_READ) {
 		tape->buffer_head++;
 #if USE_IOTRACE
 		IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
@@ -2858,8 +2834,9 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 		}
 		pc = idetape_next_pc_storage(drive);
 		idetape_create_read_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
-			break;
-		case IDETAPE_WRITE_RQ:
+		goto out;
+	}
+	if (rq->flags & REQ_IDETAPE_WRITE) {
 		tape->buffer_head++;
 #if USE_IOTRACE
 		IO_trace(IO_IDETAPE_FIFO, tape->pipeline_head, tape->buffer_head, tape->tape_head, tape->minor);
@@ -2875,36 +2852,26 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 		}
 		pc = idetape_next_pc_storage(drive);
 		idetape_create_write_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
-			break;
-		case IDETAPE_READ_BUFFER_RQ:
+		goto out;
+	}
+	if (rq->flags & REQ_IDETAPE_READ_BUFFER) {
 		tape->postpone_cnt = 0;
 		pc = idetape_next_pc_storage(drive);
 		idetape_create_read_buffer_cmd(tape, pc, rq->current_nr_sectors, (struct idetape_bh *)rq->special);
-			break;
-		case IDETAPE_ABORTED_WRITE_RQ:
-			rq->flags = IDETAPE_WRITE_RQ;
-			idetape_end_request(drive, IDETAPE_ERROR_EOD, 0);
-			return ide_stopped;
-		case IDETAPE_ABORTED_READ_RQ:
-#if IDETAPE_DEBUG_LOG
-			if (tape->debug_level >= 2)
-				printk(KERN_INFO "ide-tape: %s: detected aborted read rq\n", tape->name);
-#endif
-			rq->flags = IDETAPE_READ_RQ;
-			idetape_end_request(drive, IDETAPE_ERROR_EOD, 0);
-			return ide_stopped;
-		case IDETAPE_PC_RQ1:
+		goto out;
+	}
+	if (rq->flags & REQ_IDETAPE_PC1) {
 		pc = (idetape_pc_t *) rq->buffer;
-			rq->flags = IDETAPE_PC_RQ2;
-			break;
-		case IDETAPE_PC_RQ2:
+		rq->flags &= ~(REQ_IDETAPE_PC1);
+		rq->flags |= REQ_IDETAPE_PC2;
+		goto out;
+	}
+	if (rq->flags & REQ_IDETAPE_PC2) {
 		idetape_media_access_finished(drive);
 		return ide_stopped;
-		default:
-			printk(KERN_ERR "ide-tape: bug in IDETAPE_RQ_CMD macro\n");
-			idetape_end_request(drive, 0, 0);
-			return ide_stopped;
 	}
+	BUG();
+out:
 	return idetape_issue_packet_command(drive, pc);
 }
 
@@ -3196,7 +3163,7 @@ static void idetape_wait_for_request (ide_drive_t *drive, struct request *rq)
 	idetape_tape_t *tape = drive->driver_data;
 
 #if IDETAPE_DEBUG_BUGS
-	if (rq == NULL || !IDETAPE_RQ_CMD(rq->flags)) {
+	if (rq == NULL || !idetape_request(rq)) {
 		printk (KERN_ERR "ide-tape: bug: Trying to sleep on non-valid request\n");
 		return;
 	}
@@ -3302,9 +3269,9 @@ static int __idetape_queue_pc_tail (ide_drive_t *drive, idetape_pc_t *pc)
 {
 	struct request rq;
 
-	ide_init_drive_cmd(&rq);
+	memset(&rq, 0, sizeof(rq));
+	rq.flags = REQ_IDETAPE_PC1;
 	rq.buffer = (char *) pc;
-	rq.flags = IDETAPE_PC_RQ1;
 	return ide_do_drive_cmd(drive, &rq, ide_wait);
 }
 
@@ -3579,16 +3546,16 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct
 	}
 #endif /* IDETAPE_DEBUG_BUGS */	
 
-	ide_init_drive_cmd(&rq);
-	rq.special = (void *)bh;
+	memset(&rq, 0, sizeof(rq));
 	rq.flags = cmd;
+	rq.special = (void *)bh;
 	rq.sector = tape->first_frame_position;
 	rq.nr_sectors = rq.current_nr_sectors = blocks;
 	if (tape->onstream)
 		tape->postpone_cnt = 600;
 	(void) ide_do_drive_cmd(drive, &rq, ide_wait);
 
-	if (cmd != IDETAPE_READ_RQ && cmd != IDETAPE_WRITE_RQ)
+	if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
 		return 0;
 
 	if (tape->merge_stage)
@@ -3623,14 +3590,14 @@ static void idetape_onstream_read_back_buffer (ide_drive_t *drive)
 			first = stage;
 		aux = stage->aux;
 		p = stage->bh->b_data;
-		idetape_queue_rw_tail(drive, IDETAPE_READ_BUFFER_RQ, tape->capabilities.ctl, stage->bh);
+		idetape_queue_rw_tail(drive, REQ_IDETAPE_READ_BUFFER, tape->capabilities.ctl, stage->bh);
 #if ONSTREAM_DEBUG
 		if (tape->debug_level >= 2)
 			printk(KERN_INFO "ide-tape: %s: read back logical block %d, data %x %x %x %x\n", tape->name, logical_blk_num, *p++, *p++, *p++, *p++);
 #endif
 		rq = &stage->rq;
-		ide_init_drive_cmd(rq);
-		rq->flags = IDETAPE_WRITE_RQ;
+		memset(rq, 0, sizeof(*rq));
+		rq->flags = REQ_IDETAPE_WRITE;
 		rq->sector = tape->first_frame_position;
 		rq->nr_sectors = rq->current_nr_sectors = tape->capabilities.ctl;
 		idetape_init_stage(drive, stage, OS_FRAME_TYPE_DATA, logical_blk_num++);
@@ -3900,12 +3867,12 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
 			 *	Linux is short on memory. Fallback to
 			 *	non-pipelined operation mode for this request.
 			 */
-			return idetape_queue_rw_tail(drive, IDETAPE_WRITE_RQ, blocks, tape->merge_stage->bh);
+			return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
 		}
 	}
 	rq = &new_stage->rq;
-	ide_init_drive_cmd(rq);
-	rq->flags = IDETAPE_WRITE_RQ;
+	memset(rq, 0, sizeof(*rq));
+	rq->flags = REQ_IDETAPE_WRITE;
 	/* Doesn't actually matter - We always assume sequential access */
 	rq->sector = tape->first_frame_position;
 	rq->nr_sectors = rq->current_nr_sectors = blocks;
@@ -4093,7 +4060,7 @@ static int idetape_initiate_read (ide_drive_t *drive, int max_stages)
 		 *	is switched from completion mode to buffer available
 		 *	mode.
 		 */
-		bytes_read = idetape_queue_rw_tail(drive, IDETAPE_READ_RQ, 0, tape->merge_stage->bh);
+		bytes_read = idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 0, tape->merge_stage->bh);
 		if (bytes_read < 0) {
 			__idetape_kfree_stage(tape->merge_stage);
 			tape->merge_stage = NULL;
@@ -4103,8 +4070,8 @@ static int idetape_initiate_read (ide_drive_t *drive, int max_stages)
 	}
 	if (tape->restart_speed_control_req)
 		idetape_restart_speed_control(drive);
-	ide_init_drive_cmd(&rq);
-	rq.flags = IDETAPE_READ_RQ;
+	memset(&rq, 0, sizeof(rq));
+	rq.flags = REQ_IDETAPE_READ;
 	rq.sector = tape->first_frame_position;
 	rq.nr_sectors = rq.current_nr_sectors = blocks;
 	if (!test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags) &&
@@ -4242,7 +4209,7 @@ static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
 		}
 		if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
 		 	return 0;
-		return idetape_queue_rw_tail(drive, IDETAPE_READ_RQ, blocks, tape->merge_stage->bh);
+		return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks, tape->merge_stage->bh);
 	}
 	rq_ptr = &tape->first_stage->rq;
 	bytes_read = tape->tape_block_size * (rq_ptr->nr_sectors - rq_ptr->current_nr_sectors);
@@ -4308,7 +4275,7 @@ static void idetape_pad_zeros (ide_drive_t *drive, int bcount)
 			count -= atomic_read(&bh->b_count);
 			bh = bh->b_reqnext;
 		}
-		idetape_queue_rw_tail(drive, IDETAPE_WRITE_RQ, blocks, tape->merge_stage->bh);
+		idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
 	}
 }
 
@@ -4788,7 +4755,7 @@ static void idetape_update_last_marker (ide_drive_t *drive, int last_mark_addr,
 			"tape block %d\n", tape->last_frame_position);
 #endif
 	idetape_position_tape(drive, last_mark_addr, 0, 0);
-	if (!idetape_queue_rw_tail(drive, IDETAPE_READ_RQ, 1, stage->bh)) {
+	if (!idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 1, stage->bh)) {
 		printk(KERN_INFO "ide-tape: %s: couldn't read last marker\n",
 			tape->name);
 		__idetape_kfree_stage(stage);
@@ -4809,7 +4776,7 @@ static void idetape_update_last_marker (ide_drive_t *drive, int last_mark_addr,
 #endif
 	aux->next_mark_addr = htonl(next_mark_addr);
 	idetape_position_tape(drive, last_mark_addr, 0, 0);
-	if (!idetape_queue_rw_tail(drive, IDETAPE_WRITE_RQ, 1, stage->bh)) {
+	if (!idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 1, stage->bh)) {
 		printk(KERN_INFO "ide-tape: %s: couldn't write back marker "
 			"frame at %d\n", tape->name, last_mark_addr);
 		__idetape_kfree_stage(stage);
@@ -4845,7 +4812,7 @@ static void idetape_write_filler (ide_drive_t *drive, int block, int cnt)
 
 	strcpy(stage->bh->b_data, "Filler");
 	while (cnt--) {
-		if (!idetape_queue_rw_tail(drive, IDETAPE_WRITE_RQ, 1, stage->bh)) {
+		if (!idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 1, stage->bh)) {
 			printk(KERN_INFO "ide-tape: %s: write_filler: "
 				"couldn't write header frame\n", tape->name);
 			__idetape_kfree_stage(stage);
@@ -4880,7 +4847,7 @@ static void __idetape_write_header (ide_drive_t *drive, int block, int cnt)
 	header.partition.eod_frame_addr = htonl(tape->eod_frame_addr);
 	memcpy(stage->bh->b_data, &header, sizeof(header));
 	while (cnt--) {
-		if (!idetape_queue_rw_tail(drive, IDETAPE_WRITE_RQ, 1, stage->bh)) {
+		if (!idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 1, stage->bh)) {
 			printk(KERN_INFO "ide-tape: %s: couldn't write "
 				"header frame\n", tape->name);
 			__idetape_kfree_stage(stage);
@@ -5013,7 +4980,7 @@ static ssize_t idetape_chrdev_write (struct file *file, const char *buf,
 		 *	is switched from completion mode to buffer available
 		 *	mode.
 		 */
-		retval = idetape_queue_rw_tail(drive, IDETAPE_WRITE_RQ, 0, tape->merge_stage->bh);
+		retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh);
 		if (retval < 0) {
 			__idetape_kfree_stage(tape->merge_stage);
 			tape->merge_stage = NULL;
@@ -5487,7 +5454,7 @@ static int __idetape_analyze_headers (ide_drive_t *drive, int block)
 		printk(KERN_INFO "ide-tape: %s: reading header\n", tape->name);
 #endif
 	idetape_position_tape(drive, block, 0, 0);
-	if (!idetape_queue_rw_tail(drive, IDETAPE_READ_RQ, 1, stage->bh)) {
+	if (!idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 1, stage->bh)) {
 		printk(KERN_INFO "ide-tape: %s: couldn't read header frame\n",
 			tape->name);
 		__idetape_kfree_stage(stage);

include/linux/blkdev.h

@@ -193,6 +193,11 @@ enum rq_flag_bits {
 	__REQ_PM_SUSPEND,	/* suspend request */
 	__REQ_PM_RESUME,	/* resume request */
 	__REQ_PM_SHUTDOWN,	/* shutdown request */
+	__REQ_IDETAPE_PC1,	/* packet command (first stage) */
+	__REQ_IDETAPE_PC2,	/* packet command (second stage) */
+	__REQ_IDETAPE_READ,
+	__REQ_IDETAPE_WRITE,
+	__REQ_IDETAPE_READ_BUFFER,
 	__REQ_NR_BITS,		/* stops here */
 };
 
@@ -218,6 +223,11 @@ enum rq_flag_bits {
 #define REQ_PM_SUSPEND	(1 << __REQ_PM_SUSPEND)
 #define REQ_PM_RESUME	(1 << __REQ_PM_RESUME)
 #define REQ_PM_SHUTDOWN	(1 << __REQ_PM_SHUTDOWN)
+#define REQ_IDETAPE_PC1 (1 << __REQ_IDETAPE_PC1)
+#define REQ_IDETAPE_PC2 (1 << __REQ_IDETAPE_PC2)
+#define REQ_IDETAPE_READ	(1 << __REQ_IDETAPE_READ)
+#define REQ_IDETAPE_WRITE	(1 << __REQ_IDETAPE_WRITE)
+#define REQ_IDETAPE_READ_BUFFER	(1 << __REQ_IDETAPE_READ_BUFFER)
 
 /*
  * State information carried for REQ_PM_SUSPEND and REQ_PM_RESUME