Re: [PATCH 3/3] ide-{cd,floppy}: do not map all cmds to an sg

Bartlomiej Zolnierkiewicz
2009-03-05T12:10:45Z

Hi,

On Wednesday 04 March 2009, Borislav Petkov wrote:
> ... since some do not transfer any data from the drive and
> rq->buffer is unset leading to an OOPS when checking VM translations
> (CONFIG_DEBUG_VIRTUAL).
>
> Tested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Signed-off-by: Borislav Petkov <petkovbb@gmail.com>

Thanks for fixing it but I worry that the patch is not entirely correct
(why o why did you have to throw in unrelated changes...?)

also ideally there should have been two patches:
- minimal bugfix for the buggy patch
- unification/cleanup of PIO sg setup

> ---
> drivers/ide/ide-atapi.c | 9 ++++++++-
> drivers/ide/ide-cd.c | 4 ----
> drivers/ide/ide-floppy.c | 4 ----
> 3 files changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
> index a5596a6..ef78cbf 100644
> --- a/drivers/ide/ide-atapi.c
> +++ b/drivers/ide/ide-atapi.c
> @@ -570,7 +570,7 @@ static ide_startstop_t ide_transfer_pc(ide_drive_t *drive)
>
> ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_cmd *cmd)
> {
> - struct ide_atapi_pc *pc;
> + struct ide_atapi_pc *uninitialized_var(pc);
> ide_hwif_t *hwif = drive->hwif;
> ide_expiry_t *expiry = NULL;
> struct request *rq = hwif->rq;
> @@ -587,6 +587,7 @@ ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_cmd *cmd)
>
> if (drive->dma)
> drive->dma = !ide_dma_prepare(drive, cmd);
> +

?

> } else {
> pc = drive->pc;
>
> @@ -614,6 +615,12 @@ ide_startstop_t ide_issue_pc(ide_drive_t *drive, struct ide_cmd *cmd)
> : WAIT_TAPE_CMD;
> }
>
> + if (drive->media != ide_tape &&
> + !drive->dma && (blk_fs_request(rq) || rq->data_len)) {
> + ide_init_sg_cmd(cmd, blk_rq_bytes(rq));
> + ide_map_sg(drive, cmd);
> + }
> +
> ide_init_packet_cmd(cmd, tf_flags, bcount, drive->dma);
>
> (void)do_rw_taskfile(drive, cmd);
> diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c
> index 091d414..106cacb 100644
> --- a/drivers/ide/ide-cd.c
> +++ b/drivers/ide/ide-cd.c
> @@ -916,10 +916,6 @@ static ide_startstop_t ide_cd_do_request(ide_drive_t *drive, struct request *rq,
>
> cmd.rq = rq;
>
> - ide_init_sg_cmd(&cmd,
> - blk_fs_request(rq) ? (rq->nr_sectors << 9) : rq->data_len);
> - ide_map_sg(drive, &cmd);
> -
> return ide_issue_pc(drive, &cmd);
> out_end:
> nsectors = rq->hard_nr_sectors;
> diff --git a/drivers/ide/ide-floppy.c b/drivers/ide/ide-floppy.c
> index 2f8f453..b91deef 100644
> --- a/drivers/ide/ide-floppy.c
> +++ b/drivers/ide/ide-floppy.c
> @@ -281,10 +281,6 @@ static ide_startstop_t ide_floppy_do_request(ide_drive_t *drive,
> cmd.tf_flags |= IDE_TFLAG_WRITE;
>
> cmd.rq = rq;
> -
> - ide_init_sg_cmd(&cmd, pc->req_xfer);

There was a reason for using ->req_xfer.

I don't see where rq->data_len is set for REQ_TYPE_SPECIAL requests
(ide_queue_pc_tail() and friends)?

> - ide_map_sg(drive, &cmd);
> -
> pc->rq = rq;
>
> return ide_floppy_issue_pc(drive, &cmd, pc);