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

Bartlomiej Zolnierkiewicz
2009-03-11T17:01:11Z

On Tuesday 10 March 2009, Borislav Petkov wrote:
> Hi,
>
> > If the mainline is broken sg fix can wait but to be honest I don't see much
> > point in delaying it (it is an independent problem and the bugfix should be
> > a completely safe one-liner).
>
> --
> From: Borislav Petkov <petkovbb@gmail.com>
> Date: Tue, 10 Mar 2009 07:04:52 +0100
> Subject: [PATCH] ide-floppy: do not map dataless cmds to an sg
>
> since it fails the virt_to_page() translation check with DEBUG_VIRTUAL
> enabled.
>
> Signed-off-by: Borislav Petkov <petkovbb@gmail.com>

I applied it with some changes:

> ---
> drivers/ide/ide-atapi.c | 12 ++++++++++++
> drivers/ide/ide-floppy.c | 6 ++++--
> 2 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
> index a5596a6..11a680c 100644
> --- a/drivers/ide/ide-atapi.c
> +++ b/drivers/ide/ide-atapi.c
> @@ -90,6 +90,12 @@ static void ide_queue_pc_head(ide_drive_t *drive, struct gendisk *disk,
> rq->cmd_flags |= REQ_PREEMPT;
> rq->buffer = (char *)pc;
> rq->rq_disk = disk;
> +
> + if (pc->req_xfer) {
> + rq->data = pc->buf;
> + rq->data_len = pc->req_xfer;
> + }
> +
> memcpy(rq->cmd, pc->c, 12);
> if (drive->media == ide_tape)
> rq->cmd[13] = REQ_IDETAPE_PC1;
> @@ -112,6 +118,12 @@ int ide_queue_pc_tail(ide_drive_t *drive, struct gendisk *disk,
> rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
> rq->cmd_type = REQ_TYPE_SPECIAL;
> rq->buffer = (char *)pc;
> +
> + if (pc->req_xfer) {
> + rq->data = pc->buf;
> + rq->data_len = pc->req_xfer;
> + }
> +
> memcpy(rq->cmd, pc->c, 12);
> if (drive->media == ide_tape)
> rq->cmd[13] = REQ_IDETAPE_PC1;

ide-atapi.c part doesn't seem to be needed for fixing the issue
so I removed it (IMO it would fit much better with your sg setup
cleanup patch than this one)

> diff --git a/drivers/ide/ide-floppy.c b/drivers/ide/ide-floppy.c
> index 2f8f453..2b4868d 100644
> --- a/drivers/ide/ide-floppy.c
> +++ b/drivers/ide/ide-floppy.c
> @@ -282,8 +282,10 @@ static ide_startstop_t ide_floppy_do_request(ide_drive_t *drive,
>
> cmd.rq = rq;
>
> - ide_init_sg_cmd(&cmd, pc->req_xfer);
> - ide_map_sg(drive, &cmd);
> + if (blk_fs_request(rq) || pc->req_xfer) {

ditto for blk_fs_request(rq) check

> + ide_init_sg_cmd(&cmd, pc->req_xfer);
> + ide_map_sg(drive, &cmd);
> + }
>
> pc->rq = rq;

Thanks,
Bart