Commit b3071d19 authored by Tejun Heo's avatar Tejun Heo
Browse files

ide-atapi,tape,floppy: allow ->pc_callback() to change rq->data_len 



Impact: allow residual count implementation in ->pc_callback()

rq->data_len has two duties - carrying the number of input bytes on
issue and carrying residual count back to the issuer on completion.
ide-atapi completion callback ->pc_callback() is the right place to do
this but currently ide-atapi depends on rq->data_len carrying the
original request size after calling ->pc_callback() to complete the pc
request.

This patch makes ide_pc_intr(), ide_tape_issue_pc() and
ide_floppy_issue_pc() cache length to complete before calling
->pc_callback() so that it can modify rq->data_len as necessary.

Note: As using rq->data_len for two purposes can make cases like this
      incorrect in subtle ways, future changes will introduce separate
      field for residual count.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
parent ea7066af

drivers/ide/ide-atapi.c

+10 −6
Original line number Diff line number Diff line
@@ -409,6 +409,16 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive) 
		if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) && (stat & ATA_DSC) == 0)

			dsc = 1;



		/*

		 * ->pc_callback() might change rq->data_len for

		 * residual count, cache total length.

		 */

		if (!blk_special_request(rq) &&

		    (drive->media == ide_tape && !rq->bio))

			done = ide_rq_bytes(rq);        /* FIXME */

		else

			done = blk_rq_bytes(rq);



		/* Command finished - Call the callback function */

		uptodate = drive->pc_callback(drive, dsc);
@@ -417,7 +427,6 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive) 


		if (blk_special_request(rq)) {

			rq->errors = 0;

			done = blk_rq_bytes(rq);

			error = 0;

		} else {
@@ -426,11 +435,6 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive) 
					rq->errors = -EIO;

			}



			if (drive->media == ide_tape && !rq->bio)

				done = ide_rq_bytes(rq); /* FIXME */

			else

				done = blk_rq_bytes(rq);



			error = uptodate ? 0 : -EIO;

		}

drivers/ide/ide-floppy.c

+4 −1
Original line number Diff line number Diff line
@@ -134,14 +134,17 @@ static ide_startstop_t ide_floppy_issue_pc(ide_drive_t *drive, 
	drive->pc = pc;



	if (pc->retries > IDEFLOPPY_MAX_PC_RETRIES) {

		unsigned int done = blk_rq_bytes(drive->hwif->rq);



		if (!(pc->flags & PC_FLAG_SUPPRESS_ERROR))

			ide_floppy_report_error(floppy, pc);



		/* Giving up */

		pc->error = IDE_DRV_ERROR_GENERAL;



		drive->failed_pc = NULL;

		drive->pc_callback(drive, 0);

		ide_complete_rq(drive, -EIO, blk_rq_bytes(drive->hwif->rq));

		ide_complete_rq(drive, -EIO, done);

		return ide_stopped;

	}

drivers/ide/ide-tape.c

+4 −1
Original line number Diff line number Diff line
@@ -622,6 +622,8 @@ static ide_startstop_t ide_tape_issue_pc(ide_drive_t *drive, 


	if (pc->retries > IDETAPE_MAX_PC_RETRIES ||

		(pc->flags & PC_FLAG_ABORT)) {

		unsigned int done = blk_rq_bytes(drive->hwif->rq);



		/*

		 * We will "abort" retrying a packet command in case legitimate

		 * error code was received (crossing a filemark, or end of the
@@ -641,9 +643,10 @@ static ide_startstop_t ide_tape_issue_pc(ide_drive_t *drive, 
			/* Giving up */

			pc->error = IDE_DRV_ERROR_GENERAL;

		}



		drive->failed_pc = NULL;

		drive->pc_callback(drive, 0);

		ide_complete_rq(drive, -EIO, blk_rq_bytes(drive->hwif->rq));

		ide_complete_rq(drive, -EIO, done);

		return ide_stopped;

	}

	debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);

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