ide-atapi,tape,floppy: allow ->pc_callback() to change rq->data_len
Tejun Heo [Sat, 18 Apr 2009 23:46:02 +0000 (08:46 +0900)]
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: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>

drivers/ide/ide-atapi.c
drivers/ide/ide-floppy.c
drivers/ide/ide-tape.c

index 5cefe12..3df5442 100644 (file)
@@ -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;
                }
 
index d20704a..537b7c5 100644 (file)
@@ -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;
        }
 
index 2b9a136..8226d52 100644 (file)
@@ -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]);