From: Shawn Lin <shawn.lin@rock-chips.com>
To: Linus Walleij <linus.walleij@linaro.org>,
Ulf Hansson <ulf.hansson@linaro.org>
Cc: shawn.lin@rock-chips.com, Adrian Hunter <adrian.hunter@intel.com>,
Pavel Machek <pavel@ucw.cz>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
kernel list <linux-kernel@vger.kernel.org>,
Seraphime Kirkovski <kirkseraph@gmail.com>
Subject: Re: 4.13 on thinkpad x220: oops when writing to SD card
Date: Fri, 8 Sep 2017 10:51:49 +0800 [thread overview]
Message-ID: <b640c98b-c534-9d66-3136-d7ca47387af9@rock-chips.com> (raw)
In-Reply-To: <CACRpkdb263SS-7H1wcp0THAwzKO7A-kE0DVUdTiuxTnuXtWVVw@mail.gmail.com>
On 2017/9/8 4:02, Linus Walleij wrote:
> On Thu, Sep 7, 2017 at 9:18 AM, Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
>> Even if this fixes the problem it seems like we are papering over the
>> real issue, which earlier fixes also did during the release cycle for
>> v4.13.
>
> I think this is the real solution to the issue.
>
>>> Another unrelated issue with mmc_init_request() is that mmc_exit_request()
>>> is not called if mmc_init_request() fails, which means mmc_init_request()
>>> must free anything it allocates when it fails.
>>
>> Yes, the situations it's just too fragile. We need to fix the behavior
>> properly, although I haven't myself been able to investigate exactly
>> how yet.
>>
>> Adding, Linus, perhaps he has some ideas.
>
> Maybe we should simply bite the bullet and do what was suggested
> by another contributor when I refactored the bounce buffer handling:
> simply delete the bounce buffer code and let any remaining (few?)
> legacy devices suffer a bit (performancewise) at the gain of way
> simpler code?
Are you in the same page with what Adrian pointed to?
IIUC, the issue is:
init_rq_fn will be called each time when trying to create new reuqest
from the pre-allocated request_list memeory pool, and exit_rq_fn will is
in the corresponding routine to free request from request_list
(blk_free_request) when finished. But if alloc_request_size fails, it
won't call exit_rq_fn, so you need to prevent memory leak on your own
error path of init_rq_fn.
But you seem to talk about removing the bounce buffer and so finally
get rid of registering init_rq_fn/exit_rq_fn? That is another thing,
and what we right now need to do is to fix the pontential memory leak.
It's quite a simple action, right? :)
>
> I am a bit hesitant about that because Pierre Ossman said it was
> actually a big win on the SDHC hosts that made use of it at one
> point.
You had removed packed cmd support to simplify the code, so I think
this is another trade-off need to ask: What you want? and keep
consistent with the direction you insisted on.
>
> Yours,
> Linus Walleij
>
>
>
next prev parent reply other threads:[~2017-09-08 2:51 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-05 19:47 4.13 on thinkpad x220: oops when writing to SD card Pavel Machek
2017-09-06 2:44 ` Shawn Lin
2017-09-06 6:03 ` Adrian Hunter
2017-09-07 7:18 ` Ulf Hansson
2017-09-07 7:53 ` Adrian Hunter
2017-09-07 10:47 ` Seraphime Kirkovski
2017-09-07 12:06 ` Ulf Hansson
2017-09-07 12:55 ` Pavel Machek
2017-09-07 15:03 ` Ulf Hansson
2017-09-08 8:51 ` Pavel Machek
2017-09-07 19:58 ` Linus Walleij
2017-09-07 20:02 ` Linus Walleij
2017-09-08 2:51 ` Shawn Lin [this message]
2017-09-12 9:42 ` Linus Walleij
2017-09-13 4:04 ` Shawn Lin
2017-10-01 9:37 ` 4.14-rc2 on thinkpad x220: out of memory when inserting mmc card Pavel Machek
2017-10-01 10:26 ` Pavel Machek
2017-10-01 10:57 ` Tetsuo Handa
2017-10-02 7:52 ` Adrian Hunter
2017-10-02 8:41 ` Pavel Machek
2017-10-02 12:06 ` Linus Walleij
2017-10-02 13:03 ` Pavel Machek
2017-10-03 6:27 ` Adrian Hunter
2017-10-23 9:31 ` Pavel Machek
2017-10-23 12:13 ` Adrian Hunter
2017-10-23 12:16 ` Linus Walleij
2017-10-23 21:27 ` Pavel Machek
2017-10-24 6:59 ` Adrian Hunter
2017-10-26 13:44 ` Linus Walleij
2017-10-02 14:09 ` Linus Walleij
2017-10-03 6:30 ` Adrian Hunter
2017-10-04 7:53 ` Linus Walleij
2017-10-04 8:01 ` Ulf Hansson
2017-10-02 14:44 ` Michal Hocko
2017-10-02 14:55 ` Tetsuo Handa
2017-09-06 7:08 4.13 on thinkpad x220: oops when writing to SD card Seraphime Kirkovski
2017-09-06 8:20 Seraphime Kirkovski
2017-09-08 9:29 ` Pavel Machek
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