ide-atapi: switch to rq->resid_len

Now that we have rq->resid_len, use it to account partial completion
amount during the lifetime of an rq, decrementing it on each successful
transfer. As a result, get rid of now unused pc->xferred.

While at it, remove noisy debug call in ide_prep_sense.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>

drivers/ide/ide-atapi.c

@@ -172,8 +172,6 @@ void ide_prep_sense(ide_drive_t *drive, struct request *rq)
 	unsigned int cmd_len, sense_len;
 	int err;
 
-	debug_log("%s: enter\n", __func__);
-
 	switch (drive->media) {
 	case ide_floppy:
 		cmd_len = 255;
@@ -370,7 +368,7 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 						     ? "write" : "read");
 			pc->flags |= PC_FLAG_DMA_ERROR;
 		} else
-			pc->xferred = blk_rq_bytes(rq);
+			rq->resid_len = 0;
 		debug_log("%s: DMA finished\n", drive->name);
 	}
 
@@ -379,7 +377,7 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 		int uptodate, error;
 
 		debug_log("Packet command completed, %d bytes transferred\n",
-			  pc->xferred);
+			  blk_rq_bytes(rq));
 
 		pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
 
@@ -467,15 +465,15 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 	ide_pio_bytes(drive, cmd, write, done);
 
 	/* Update transferred byte count */
-	pc->xferred += done;
+	rq->resid_len -= done;
 
 	bcount -= done;
 
 	if (bcount)
 		ide_pad_transfer(drive, write, bcount);
 
-	debug_log("[cmd %x] transferred %d bytes, padded %d bytes\n",
-		  rq->cmd[0], done, bcount);
+	debug_log("[cmd %x] transferred %d bytes, padded %d bytes, resid: %u\n",
+		  rq->cmd[0], done, bcount, rq->resid_len);
 
 	/* And set the interrupt handler again */
 	ide_set_handler(drive, ide_pc_intr, timeout);
@@ -643,16 +641,15 @@ ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_cmd *cmd)
 	} else {
 		pc = drive->pc;
 
-		/* We haven't transferred any data yet */
-		pc->xferred = 0;
-
 		valid_tf = IDE_VALID_DEVICE;
 		bytes = blk_rq_bytes(rq);
-
 		bcount = ((drive->media == ide_tape) ? bytes
 						     : min_t(unsigned int,
 							     bytes, 63 * 1024));
 
+		/* We haven't transferred any data yet */
+		rq->resid_len = bcount;
+
 		if (pc->flags & PC_FLAG_DMA_ERROR) {
 			pc->flags &= ~PC_FLAG_DMA_ERROR;
 			ide_dma_off(drive);

drivers/ide/ide-tape.c

@@ -301,11 +301,9 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
 	debug_log(DBG_ERR, "pc = %x, sense key = %x, asc = %x, ascq = %x\n",
 		 pc->c[0], tape->sense_key, tape->asc, tape->ascq);
 
-	/* Correct pc->xferred by asking the tape.	 */
+	/* correct remaining bytes to transfer */
 	if (pc->flags & PC_FLAG_DMA_ERROR)
-		pc->xferred = blk_rq_bytes(rq) -
-			tape->blk_size *
-			get_unaligned_be32(&sense[3]);
+		rq->resid_len = tape->blk_size * get_unaligned_be32(&sense[3]);
 
 	/*
 	 * If error was the result of a zero-length read or write command,
@@ -339,7 +337,7 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
 			pc->flags |= PC_FLAG_ABORT;
 		}
 		if (!(pc->flags & PC_FLAG_ABORT) &&
-		    pc->xferred)
+		    (blk_rq_bytes(rq) - rq->resid_len))
 			pc->retries = IDETAPE_MAX_PC_RETRIES + 1;
 	}
 }
@@ -369,7 +367,8 @@ static int ide_tape_callback(ide_drive_t *drive, int dsc)
 			printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
 					"itself - Aborting request!\n");
 	} else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
-		int blocks = pc->xferred / tape->blk_size;
+		unsigned int blocks =
+			(blk_rq_bytes(rq) - rq->resid_len) / tape->blk_size;
 
 		tape->avg_size += blocks * tape->blk_size;
 
@@ -381,7 +380,6 @@ static int ide_tape_callback(ide_drive_t *drive, int dsc)
 		}
 
 		tape->first_frame += blocks;
-		rq->resid_len = blk_rq_bytes(rq) - blocks * tape->blk_size;
 
 		if (pc->error) {
 			uptodate = 0;

include/linux/ide.h

@@ -357,8 +357,6 @@ struct ide_atapi_pc {
 
 	/* bytes to transfer */
 	int req_xfer;
-	/* bytes actually transferred */
-	int xferred;
 
 	/* data buffer */
 	u8 *buf;