Re: [PATCH ide-dev-2.6] ide: ide_dma_intr oops fix

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

On Thu, 03 Mar 2005 15:57:18 +0900, Tejun Heo <htejun@gmail.com> wrote:
>   Hello, Jens.
> 
> Jens Axboe wrote:
> > On Thu, Mar 03 2005, Tejun Heo wrote:
> >
> >> Hello, Bartlomiej.
> >>
> >> This patch fixes ide_dma_intr() oops which occurs for TASKFILE ioctl
> >>using DMA dataphses.  This is against the latest ide-dev-2.6 tree +
> >>all your recent 9 patches.
> >>
> >> Signed-off-by: Tejun Heo <htejun@gmail.com>
> >>
> >>Index: linux-taskfile-ng/drivers/ide/ide-dma.c
> >>===================================================================
> >>--- linux-taskfile-ng.orig/drivers/ide/ide-dma.c      2005-03-03 11:59:16.485582413 +0900
> >>+++ linux-taskfile-ng/drivers/ide/ide-dma.c   2005-03-03 12:00:07.753376048 +0900
> >>@@ -175,10 +175,14 @@ ide_startstop_t ide_dma_intr (ide_drive_
> >>      if (OK_STAT(stat,DRIVE_READY,drive->bad_wstat|DRQ_STAT)) {
> >>              if (!dma_stat) {
> >>                      struct request *rq = HWGROUP(drive)->rq;
> >>-                     ide_driver_t *drv;
> >>
> >>-                     drv = *(ide_driver_t **)rq->rq_disk->private_data;;
> >>-                     drv->end_request(drive, 1, rq->nr_sectors);
> >>+                     if (rq->rq_disk) {
> >>+                             ide_driver_t *drv;
> >>+
> >>+                             drv = *(ide_driver_t **)rq->rq_disk->private_data;;
> >>+                             drv->end_request(drive, 1, rq->nr_sectors);
> >>+                     } else
> >>+                             ide_end_request(drive, 1, rq->nr_sectors);
> >>                      return ide_stopped;
> >>              }
> >>              printk(KERN_ERR "%s: dma_intr: bad DMA status (dma_stat=%x)\n",
> >
> > Why not just set rq_disk for taskfile requests as well, seems a lot
> > cleaner than special casing the end_request handling.
> 
>   Just because other places were fixed this way and the whole drive
> command issue/completion codes are just about to be restructured.  Above
> code will go away soon.  Please consider it a quick fix.
> 
>   Thanks.

Because struct gendisk is now allocated by device drivers (like in SCSI
subsystem) rq_disk can't be set for REQ_DRIVE_TASKFILE requests
(for some requests it can be set but better to keep it consistent).