linux-kernel - RE: [PATCH] mmc: block: disable the reliable write If the card does not support CMD23

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Message-ID: <BLU168-W82A87998B6D70A69827831D6600@phx.gbl>
Date:	Wed, 26 Aug 2015 20:38:14 +0800
From:	LIYONG <sdliyong@...il.com>
To:	Shawn Lin <shawn.lin@...k-chips.com>,
	Ulf Hansson <ulf.hansson@...aro.org>
CC:	Chris Ball <chris@...ntf.net>,
	linux-mmc <linux-mmc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] mmc: block: disable the reliable write If the card does
 not support CMD23

Thanks Shawn. I got your point. You mean we can remove the || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23) at line 1468.

But considering this case: The do_rel_wr = false and the card does support CMD23.
do_rel_wr = false; 
!(card->quirks & MMC_QUIRK_BLK_NO_CMD23) = true;

At line 1468, do_rel_wr || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23) should be true;

If re remove the || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23), it will be false

It seems that we cannot modify the line 1468?

Thanks,
Yong Li
----------------------------------------
> Subject: Re: [PATCH] mmc: block: disable the reliable write If the card does not support CMD23
> To: sdliyong@...il.com; ulf.hansson@...aro.org
> CC: shawn.lin@...k-chips.com; chris@...ntf.net; linux-mmc@...r.kernel.org; linux-kernel@...r.kernel.org
> From: shawn.lin@...k-chips.com
> Date: Wed, 26 Aug 2015 15:20:11 +0800
>
> On 2015/8/26 14:15, LIYONG wrote:
>> Hi Uffe,
>>
>> The bool variable do_rel_wr is used on line 1408 and line 1436:
>> if (brq->data.blocks> 1 || do_rel_wr) {
>> /* SPI multiblock writes terminate using a special
>> * token, not a STOP_TRANSMISSION request.
>> */
>>
>> if (do_rel_wr)
>> mmc_apply_rel_rw(brq, card, req);
>>
>> If a card does not support CMD23, I think we need to set the do_rel_wr to false at the beginning of this mmc_blk_rw_rq_prep function
>
> Hi Yong,
>
> You miss the point, Ulf means you should remove
> "(do_rel_wr || !(card->quirks & MMC_QUIRK_BLK_NO_CMD23)" as well.
>
> No need to check card->quirks & MMC_QUIRK_BLK_NO_CMD23 twice, you have
> did it while checking do_rel_wr, right?
>
> bool do_rel_wr = ((req->cmd_flags & REQ_FUA) ||
> (req->cmd_flags & REQ_META)) &&
> (rq_data_dir(req) == WRITE) &&
> - (md->flags & MMC_BLK_REL_WR);
> + (md->flags & MMC_BLK_REL_WR) &&
> + !(card->quirks & MMC_QUIRK_BLK_NO_CMD23);
>
>>
>> Thanks,
>> Yong Li
>> ----------------------------------------
>>> Date: Tue, 25 Aug 2015 14:06:43 +0200
>>> Subject: Re: [PATCH] mmc: block: disable the reliable write If the card does not support CMD23
>>> From: ulf.hansson@...aro.org
>>> To: sdliyong@...il.com
>>> CC: chris@...ntf.net; linux-mmc@...r.kernel.org; linux-kernel@...r.kernel.org
>>>
>>> On 14 August 2015 at 09:30, <sdliyong@...il.com> wrote:
>>>> From: Yong Li <sdliyong@...il.com>
>>>>
>>>> Signed-off-by: Yong Li <sdliyong@...il.com>
>>>> ---
>>>> drivers/mmc/card/block.c | 3 ++-
>>>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>>>> index 452782b..d9e3c45 100644
>>>> --- a/drivers/mmc/card/block.c
>>>> +++ b/drivers/mmc/card/block.c
>>>> @@ -1366,7 +1366,8 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
>>>> bool do_rel_wr = ((req->cmd_flags & REQ_FUA) ||
>>>> (req->cmd_flags & REQ_META)) &&
>>>> (rq_data_dir(req) == WRITE) &&
>>>> - (md->flags & MMC_BLK_REL_WR);
>>>> + (md->flags & MMC_BLK_REL_WR) &&
>>>> + !(card->quirks & MMC_QUIRK_BLK_NO_CMD23);
>>>
>>> Further down in mmc_blk_rw_rq_prep() we check for
>>> MMC_QUIRK_BLK_NO_CMD23. That check becomes redundant after this
>>> change, please remove that check as a part of this patch as well.
>>>
>>>>
>>>> memset(brq, 0, sizeof(struct mmc_blk_request));
>>>> brq->mrq.cmd = &brq->cmd;
>>>> --
>>>> 2.1.0
>>>>
>>>
>>> Kind regards
>>> Uffe
>> --
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>>
>>
>>
>
>
> --
> Best Regards
> Shawn Lin
>
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