Re: [PATCH] scsi: hpsa: fix multiple issues in path_info_show

From: Rasmus Villemoes
Date: Sat Nov 14 2015 - 10:25:17 EST

On Wed, Oct 28 2015, Don Brace <brace77070@xxxxxxxxx> wrote:

> On 10/27/2015 05:16 PM, Rasmus Villemoes wrote:
>> I'm not familiar with this code, but path_info_show() (added in
>> 8270b86243658 "hpsa: add sysfs entry path_info to show box and
>> bay information") seems to be broken in multiple ways.
>> We can fix all of that and get rid of the 400 byte stack buffer by
>> simply writing directly to the given output buffer, which the upper
>> layer guarantees is at least PAGE_SIZE. s[c]nprintf doesn't care where
>> it is writing to, so this doesn't make the spin lock hold time any
>> longer. Using scnprintf ensures that output_len always represents the
>> number of bytes actually written to the buffer, so we'll report the
>> proper amount to the upper layer.
>> Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
> Thanks, I added this to my current patch set. This patch will be up
> with you as the author soon.

I see it in mainline now. May I ask why 6 out of 7 scnprintfs were
changed (back) to snprintf? I don't think there's any functional
difference as long as PAGE_SIZE is indeed sufficient, but mixing
snprintf and scnprintf is pretty odd, and there's now a discrepancy
between the commit log and the patch which wasn't in my original - I'd
expect a "[use snprintf because xyz]" note added if the change was


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