linux-kernel - Re: [PATCH] strstrip incorrectly marked __must

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Date:	Tue, 03 Nov 2009 13:10:48 -0600
From:	James Bottomley <James.Bottomley@...e.de>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	linux-scsi@...r.kernel.org,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] strstrip incorrectly marked __must_check

On Tue, 2009-11-03 at 10:59 -0800, Andrew Morton wrote:
> On Tue, 03 Nov 2009 12:38:08 -0600
> James Bottomley <James.Bottomley@...e.de> wrote:
> 
> > strstrip strips whitespace from the beginning and end of a string.  I
> > agree you have to take the returned pointer if you want to strip from
> > the beginning.  However, if you wish to keep the whitespace at the
> > beginning and only wish strstrip to remove it from the end, then it's
> > entirely legitimate to discard the returned pointer.
> > 
> > This is what we have in drivers/scsi/ipr.c and the patch to make
> > strstrip __must_check is now causing SCSI spurious warnings in that
> > code.
> > 
> 
> Would prefer to keep the warning and to patch ipr.c, please.  We found
> I think three call sites which were incorrectly ignoring the strstrip()
> return value and it's reasonable to fear that others will make the same
> mistake in the future.

What's the problem with the mistake ... additional leading whitespace?

> And maybe ipr.c _should_ be patched.  Right now it's assuming that the
> string coming back from the device has no leading whitespace.  Why trim
> any possible trailing whitespace but not trim any possible leading
> whitespace?

I think it doesn't care.  It wants to append an error code to the
string, and to make it more visible it wants to strip trailing
whitespace before doing so. 

> Or..
> 
> /*
>  * Comment goes here
>  */
> static inline void strsrip_tail(char *str)
> {
> 	char *x __used;
> 	x = strstrip(str);
> }

Yes, I could go for that ... I just don't see such a problem with the
currently overloaded uses of strstrip.

James


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