From:   Thomas Zimmermann <tzimmermann@suse.de>
To:     deller@gmx.de, paulus@samba.org, benh@kernel.crashing.org,
        linux@armlinux.org.uk, pjones@redhat.com, timur@kernel.org,
        adaplas@gmail.com, s.hauer@pengutronix.de, shawnguo@kernel.org,
        mbroemme@libmpq.org, thomas@winischhofer.net,
        James.Bottomley@HansenPartnership.com, spock@gentoo.org,
        sudipm.mukherjee@gmail.com, teddy.wang@siliconmotion.com,
        geert+renesas@glider.be, corbet@lwn.net
Cc:     linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org,
        Thomas Zimmermann <tzimmermann@suse.de>
Subject: [PATCH 22/99] fbdev/fsl-diu-fb: Duplicate video-mode option string
Date:   Mon,  6 Mar 2023 16:58:59 +0100
Message-Id: <20230306160016.4459-23-tzimmermann@suse.de>
In-Reply-To: <20230306160016.4459-1-tzimmermann@suse.de>
References: <20230306160016.4459-1-tzimmermann@suse.de>
MIME-Version: 1.0
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Assume that the driver does not own the option string or its substrings
and hence duplicate the option string for the video mode. The driver only
parses the option string once as part of module initialization, so use
a static buffer to store the duplicated mode option. Linux automatically
frees the memory upon releasing the module.

Done in preparation of switching the driver to struct option_iter and
constifying the option string.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/fsl-diu-fb.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/fsl-diu-fb.c b/drivers/video/fbdev/fsl-diu-fb.c
index e332017c6af6..e01281959062 100644
--- a/drivers/video/fbdev/fsl-diu-fb.c
+++ b/drivers/video/fbdev/fsl-diu-fb.c
@@ -1858,8 +1858,17 @@ static int __init fsl_diu_setup(char *options)
 		} else if (!strncmp(opt, "bpp=", 4)) {
 			if (!kstrtoul(opt + 4, 10, &val))
 				default_bpp = val;
-		} else
-			fb_mode = opt;
+		} else {
+			static char mode_option_buf[256];
+			int ret;
+
+			ret = snprintf(mode_option_buf, sizeof(mode_option_buf), "%s", opt);
+			if (WARN(ret < 0, "fsl-diu-fb: ignoring invalid option, ret=%d\n", ret))
+				continue;
+			if (WARN(ret >= sizeof(mode_option_buf), "fsl-diu-fb: option too long\n"))
+				continue;
+			fb_mode = mode_option_buf;
+		}
 	}
 
 	return 0;
-- 
2.39.2