[PATCH] Fix IDE-CD command failure re-play

Every failed SG_IO request is replayed second time without data
transfer.  Fix the problem by immediately purging the failed SG_IO
request from the request queue.

It fixes (among others)

	http://marc.theaimsgroup.com/?t=105634805100001&r=1&w=2

where induced kernel crash occurs upon packet replay.

drivers/ide/ide-cd.c

@@ -749,12 +749,17 @@ static int cdrom_decode_status(ide_drive_t *drive, int good_stat, int *stat_ret)
 		   by transferring the semaphore from the packet
 		   command request to the request sense request. */
 
+		rq->flags |= REQ_FAILED;
 		if ((stat & ERR_STAT) != 0) {
 			wait = rq->waiting;
 			rq->waiting = NULL;
+			if ((rq->flags & REQ_BLOCK_PC) != 0) {
+				cdrom_queue_request_sense(drive, wait,
+							  rq->sense, rq);
+				return 1; /* REQ_BLOCK_PC self-cares */
+			}
 		}
 
-		rq->flags |= REQ_FAILED;
 		cdrom_end_request(drive, 0);
 
 		if ((stat & ERR_STAT) != 0)
@@ -1657,13 +1662,14 @@ static ide_startstop_t cdrom_newpc_intr(ide_drive_t *drive)
 	dma = info->dma;
 	if (dma) {
 		info->dma = 0;
-		if ((dma_error = HWIF(drive)->ide_dma_end(drive))) {
-			printk("ide-cd: dma error\n");
-			HWIF(drive)->ide_dma_off(drive);
-		}
+		dma_error = HWIF(drive)->ide_dma_end(drive);
 	}
 
 	if (cdrom_decode_status(drive, 0, &stat)) {
+		if ((stat & ERR_STAT) != 0) {
+			end_that_request_chunk(rq, 0, rq->data_len);
+			goto end_request; /* purge the whole thing... */
+		}
 		end_that_request_chunk(rq, 1, rq->data_len);
 		return ide_stopped;
 	}
@@ -1672,8 +1678,11 @@ static ide_startstop_t cdrom_newpc_intr(ide_drive_t *drive)
 	 * using dma, transfer is complete now
 	 */
 	if (dma) {
-		if (dma_error)
+		if (dma_error) {
+			printk("ide-cd: dma error\n");
+			HWIF(drive)->ide_dma_off(drive);
 			return DRIVER(drive)->error(drive, "dma error", stat);
+		}
 
 		end_that_request_chunk(rq, 1, rq->data_len);
 		rq->data_len = 0;