linux-kernel - Re: [PATCH 04/40] ide-scsi: fix Interrupt Reason checking in idescsi_pc

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Date:	Mon, 19 May 2008 07:10:32 +0200
From:	Borislav Petkov <petkovbb@...glemail.com>
To:	Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
Cc:	linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 04/40] ide-scsi: fix Interrupt Reason checking in
	idescsi_pc_intr()

On Sun, May 18, 2008 at 08:55:03PM +0200, Bartlomiej Zolnierkiewicz wrote:
> Set PC_FLAG_WRITING pc flag in idescsi_queue() (if needed)
> and then fix Interrupt Reason checking in idescsi_pc_intr().
> 
> Cc: Borislav Petkov <petkovbb@...il.com>
> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
> ---
>  drivers/scsi/ide-scsi.c |   17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> Index: b/drivers/scsi/ide-scsi.c
> ===================================================================
> --- a/drivers/scsi/ide-scsi.c
> +++ b/drivers/scsi/ide-scsi.c
> @@ -427,7 +427,15 @@ static ide_startstop_t idescsi_pc_intr (
>  		printk(KERN_ERR "ide-scsi: CoD != 0 in idescsi_pc_intr\n");
>  		return ide_do_reset (drive);
>  	}
> -	if (ireason & IO) {
> +	if (((ireason & IO) == IO) == !!(pc->flags & PC_FLAG_WRITING)) {
> +		/* Hopefully, we will never get here */
> +		printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
> +				"to %s!\n", drive->name,
> +				(ireason & IO) ? "Write" : "Read",
> +				(ireason & IO) ? "Read" : "Write");
> +		return ide_do_reset(drive);
> +	}
> +	if (!(pc->flags & PC_FLAG_WRITING)) {
>  		temp = pc->xferred + bcount;
>  		if (temp > pc->req_xfer) {
>  			if (temp > pc->buf_size) {
> @@ -436,7 +444,6 @@ static ide_startstop_t idescsi_pc_intr (
>  					"- discarding data\n");
>  				temp = pc->buf_size - pc->xferred;
>  				if (temp) {
> -					pc->flags &= ~PC_FLAG_WRITING;
>  					if (pc->sg)
>  						idescsi_input_buffers(drive, pc,
>  									temp);
> @@ -457,15 +464,11 @@ static ide_startstop_t idescsi_pc_intr (
>  			printk (KERN_NOTICE "ide-scsi: The scsi wants to send us more data than expected - allowing transfer\n");
>  #endif /* IDESCSI_DEBUG_LOG */
>  		}
> -	}
> -	if (ireason & IO) {
> -		pc->flags &= ~PC_FLAG_WRITING;
>  		if (pc->sg)
>  			idescsi_input_buffers(drive, pc, bcount);
>  		else
>  			hwif->input_data(drive, NULL, pc->cur_pos, bcount);
>  	} else {
> -		pc->flags |= PC_FLAG_WRITING;

Yeah, what was the driver doing turning on/off that flag in the irq handler? Are
those pc's getting reused in ide-scsi... I guess this is one of the bugs you
were talking about :).

>  		if (pc->sg)
>  			idescsi_output_buffers(drive, pc, bcount);
>  		else
> @@ -777,6 +780,8 @@ static int idescsi_queue (struct scsi_cm
>  
>  	memset (pc->c, 0, 12);
>  	pc->flags = 0;
> +	if (cmd->sc_data_direction == DMA_TO_DEVICE)
> +		pc->flags |= PC_FLAG_WRITING;
>  	pc->rq = rq;
>  	memcpy (pc->c, cmd->cmnd, cmd->cmd_len);
>  	pc->buf = NULL;

-- 
Regards/Gruß,
    Boris.
--
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