linux-kernel - Re: [PATCH] staging: sm750fb: always take the lock

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Message-ID: <CAMuHMdUp2JQAYz3Smb4bH=SSc6tCb2iLQG1-5uQguz_wxyybfQ@mail.gmail.com>
Date:   Mon, 26 Jun 2017 11:11:47 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     AbdAllah-MEZITI <abdallah.meziti.pro@...il.com>
Cc:     Sudip Mukherjee <sudipm.mukherjee@...il.com>,
        Teddy Wang <teddy.wang@...iconmotion.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Linux Fbdev development list <linux-fbdev@...r.kernel.org>,
        driverdevel <devel@...verdev.osuosl.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] staging: sm750fb: always take the lock

On Mon, Jun 26, 2017 at 7:45 AM, AbdAllah-MEZITI
<abdallah.meziti.pro@...il.com> wrote:
> This patch
> - will always take the lock

Why?

"The current code only takes the lock if multiple instances are in use.
 This is error-prone, and confuses static analyzers.
 As taking the lock in case of a single instance is harmful and cheap,
 change the code to always take the lock."

> - fix the sparse warning:
> drivers/staging/sm750fb/sm750.c:159:13: warning: context imbalance in 'lynxfb_ops_fillrect' - different lock contexts for basic block
> drivers/staging/sm750fb/sm750.c:231:9: warning: context imbalance in 'lynxfb_ops_copyarea' - different lock contexts for basic block
> drivers/staging/sm750fb/sm750.c:235:13: warning: context imbalance in 'lynxfb_ops_imageblit' - different lock contexts for basic block

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds