ide-cd,atapi: use bio for internal commands

Impact: unify request data buffer handling

rq->data is used mostly to pass kernel buffer through request queue
without using bio.  There are only a couple of places which still do
this in kernel and converting to bio isn't difficult.

This patch converts ide-cd and atapi to use bio instead of rq->data
for request sense and internal pc commands.  With previous change to
unify sense request handling, this is relatively easily achieved by
adding blk_rq_map_kern() during sense_rq prep and PC issue.

If blk_rq_map_kern() fails for sense, the error is deferred till sense
issue and aborts the failed command which triggered the sense.  Note
that this is a slim possibility as sense prep is done on each command
issue, so for the above condition to actually trigger, all preps since
the last sense issue till the issue of the request which would require
a sense should fail.

* do_request functions might sleep now.  This should be okay as ide
  request_fn - do_ide_request() - is invoked only from make_request
  and plug work.  Make sure this is the case by adding might_sleep()
  to do_ide_request().

* Functions which access the read sense data before the sense request
  is complete now should access bio_data(sense_rq->bio) as the sense
  buffer might have been copied during blk_rq_map_kern().

* ide-tape updated to map sg.

* cdrom_do_block_pc() now doesn't have to deal with REQ_TYPE_ATA_PC
  special case.  Simplified.

* tp_ops->output/input_data path dropped from ide_pc_intr().

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 31 insertions, 21 deletions

diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
index 972c522516f..5cefe12f562 100644
--- a/drivers/ide/ide-atapi.c
+++ b/drivers/ide/ide-atapi.c
@@ -94,16 +94,18 @@ int ide_queue_pc_tail(ide_drive_t *drive, struct gendisk *disk,
 	rq->special = (char *)pc;
 
 	if (pc->req_xfer) {
-		rq->data = pc->buf;
-		rq->data_len = pc->req_xfer;
+		error = blk_rq_map_kern(drive->queue, rq, pc->buf, pc->req_xfer,
+					GFP_NOIO);
+		if (error)
+			goto put_req;
 	}
 
 	memcpy(rq->cmd, pc->c, 12);
 	if (drive->media == ide_tape)
 		rq->cmd[13] = REQ_IDETAPE_PC1;
 	error = blk_execute_rq(drive->queue, disk, rq, 0);
+put_req:
 	blk_put_request(rq);
-
 	return error;
 }
 EXPORT_SYMBOL_GPL(ide_queue_pc_tail);
@@ -168,6 +170,7 @@ void ide_prep_sense(ide_drive_t *drive, struct request *rq)
 	struct request_sense *sense = &drive->sense_data;
 	struct request *sense_rq = &drive->sense_rq;
 	unsigned int cmd_len, sense_len;
+	int err;
 
 	debug_log("%s: enter\n", __func__);
 
@@ -193,13 +196,19 @@ void ide_prep_sense(ide_drive_t *drive, struct request *rq)
 	memset(sense, 0, sizeof(*sense));
 
 	blk_rq_init(rq->q, sense_rq);
-	sense_rq->rq_disk = rq->rq_disk;
 
-	sense_rq->data = sense;
+	err = blk_rq_map_kern(drive->queue, sense_rq, sense, sense_len,
+			      GFP_NOIO);
+	if (unlikely(err)) {
+		if (printk_ratelimit())
+			printk(KERN_WARNING "%s: failed to map sense buffer\n",
+			       drive->name);
+		return;
+	}
+
+	sense_rq->rq_disk = rq->rq_disk;
 	sense_rq->cmd[0] = GPCMD_REQUEST_SENSE;
 	sense_rq->cmd[4] = cmd_len;
-	sense_rq->data_len = sense_len;
-
 	sense_rq->cmd_type = REQ_TYPE_SENSE;
 	sense_rq->cmd_flags |= REQ_PREEMPT;
 
@@ -210,9 +219,14 @@ void ide_prep_sense(ide_drive_t *drive, struct request *rq)
 }
 EXPORT_SYMBOL_GPL(ide_prep_sense);
 
-void ide_queue_sense_rq(ide_drive_t *drive, void *special)
+int ide_queue_sense_rq(ide_drive_t *drive, void *special)
 {
-	BUG_ON(!drive->sense_rq_armed);
+	/* deferred failure from ide_prep_sense() */
+	if (!drive->sense_rq_armed) {
+		printk(KERN_WARNING "%s: failed queue sense request\n",
+		       drive->name);
+		return -ENOMEM;
+	}
 
 	drive->sense_rq.special = special;
 	drive->sense_rq_armed = false;
@@ -221,6 +235,7 @@ void ide_queue_sense_rq(ide_drive_t *drive, void *special)
 
 	elv_add_request(drive->queue, &drive->sense_rq,
 			ELEVATOR_INSERT_FRONT, 0);
+	return 0;
 }
 EXPORT_SYMBOL_GPL(ide_queue_sense_rq);
 
@@ -239,13 +254,14 @@ void ide_retry_pc(ide_drive_t *drive)
 	/* init pc from sense_rq */
 	ide_init_pc(pc);
 	memcpy(pc->c, sense_rq->cmd, 12);
-	pc->buf = sense_rq->data;
+	pc->buf = bio_data(sense_rq->bio);	/* pointer to mapped address */
 	pc->req_xfer = sense_rq->data_len;
 
 	if (drive->media == ide_tape)
 		set_bit(IDE_AFLAG_IGNORE_DSC, &drive->atapi_flags);
 
-	ide_queue_sense_rq(drive, pc);
+	if (ide_queue_sense_rq(drive, pc))
+		ide_complete_rq(drive, -EIO, blk_rq_bytes(drive->hwif->rq));
 }
 EXPORT_SYMBOL_GPL(ide_retry_pc);
 
@@ -317,7 +333,6 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 	struct ide_cmd *cmd = &hwif->cmd;
 	struct request *rq = hwif->rq;
 	const struct ide_tp_ops *tp_ops = hwif->tp_ops;
-	xfer_func_t *xferfunc;
 	unsigned int timeout, done;
 	u16 bcount;
 	u8 stat, ireason, dsc = 0;
@@ -411,7 +426,7 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 					rq->errors = -EIO;
 			}
 
-			if (drive->media == ide_tape)
+			if (drive->media == ide_tape && !rq->bio)
 				done = ide_rq_bytes(rq); /* FIXME */
 			else
 				done = blk_rq_bytes(rq);
@@ -448,16 +463,11 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
 		return ide_do_reset(drive);
 	}
 
-	xferfunc = write ? tp_ops->output_data : tp_ops->input_data;
-
-	if (drive->media == ide_floppy && pc->buf == NULL) {
+	if (drive->media == ide_tape && pc->bh)
+		done = drive->pc_io_buffers(drive, pc, bcount, write);
+	else {
 		done = min_t(unsigned int, bcount, cmd->nleft);
 		ide_pio_bytes(drive, cmd, write, done);
-	} else if (drive->media == ide_tape && pc->bh) {
-		done = drive->pc_io_buffers(drive, pc, bcount, write);
-	} else {
-		done = min_t(unsigned int, bcount, pc->req_xfer - pc->xferred);
-		xferfunc(drive, NULL, pc->cur_pos, done);
 	}
 
 	/* Update the current position */