linux-kernel - [PATCH 30/99] fbdev/gxt4500: Duplicate video-mode option string

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Message-Id: <20230306160016.4459-31-tzimmermann@suse.de>
Date:   Mon,  6 Mar 2023 16:59:07 +0100
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     deller@....de, paulus@...ba.org, benh@...nel.crashing.org,
        linux@...linux.org.uk, pjones@...hat.com, timur@...nel.org,
        adaplas@...il.com, s.hauer@...gutronix.de, shawnguo@...nel.org,
        mbroemme@...mpq.org, thomas@...ischhofer.net,
        James.Bottomley@...senPartnership.com, spock@...too.org,
        sudipm.mukherjee@...il.com, teddy.wang@...iconmotion.com,
        geert+renesas@...der.be, corbet@....net
Cc:     linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org,
        Thomas Zimmermann <tzimmermann@...e.de>
Subject: [PATCH 30/99] fbdev/gxt4500: Duplicate video-mode option string

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 constifying the option string.

Signed-off-by: Thomas Zimmermann <tzimmermann@...e.de>
---
 drivers/video/fbdev/gxt4500.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/gxt4500.c b/drivers/video/fbdev/gxt4500.c
index 5f42d3d9d6ce..61bc714693f5 100644
--- a/drivers/video/fbdev/gxt4500.c
+++ b/drivers/video/fbdev/gxt4500.c
@@ -779,12 +779,28 @@ static struct pci_driver gxt4500_driver = {
 
 static int gxt4500_init(void)
 {
+#ifndef MODULE
+	char *options;
+#endif
+
 	if (fb_modesetting_disabled("gxt4500"))
 		return -ENODEV;
 
 #ifndef MODULE
-	if (fb_get_options("gxt4500", &mode_option))
+	if (fb_get_options("gxt4500", &options))
 		return -ENODEV;
+
+	do {
+		static char mode_option_buf[256];
+		int ret;
+
+		ret = snprintf(mode_option_buf, sizeof(mode_option_buf), "%s", options);
+		if (WARN(ret < 0, "gxt4500: ignoring invalid option, ret=%d\n", ret))
+			break;
+		if (WARN(ret >= sizeof(mode_option_buf), "gxt4500: option too long\n"))
+			break;
+		mode_option = mode_option_buf;
+	} while (0);
 #endif
 
 	return pci_register_driver(&gxt4500_driver);
-- 
2.39.2