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

[Jens Axboe <axboe@suse.de>]

On Thu, Mar 03 2005, Bartlomiej Zolnierkiewicz wrote:
> 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).

Seems cleaner to store the driver in the drive structure then, no
special casing needed.

-- 
Jens Axboe