linux-kernel - [PATCH v2 032/101] fbdev/i740fb: Duplicate video-mode option string

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Message-Id: <20230309160201.5163-33-tzimmermann@suse.de>
Date:   Thu,  9 Mar 2023 17:00:52 +0100
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     deller@....de, geert+renesas@...der.be, timur@...nel.org,
        rdunlap@...radead.org, paulus@...ba.org, benh@...nel.crashing.org,
        linux@...linux.org.uk, pjones@...hat.com, adaplas@...il.com,
        s.hauer@...gutronix.de, shawnguo@...nel.org, mbroemme@...mpq.org,
        thomas@...ischhofer.net, James.Bottomley@...senPartnership.com,
        sudipm.mukherjee@...il.com, teddy.wang@...iconmotion.com,
        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 v2 032/101] fbdev/i740fb: 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. Allocate the
copy's memory with kstrdup() and free it in the module's exit function.

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

v2:
	* replace static memory with kstrdup()/kfree() (Geert)

Signed-off-by: Thomas Zimmermann <tzimmermann@...e.de>
---
 drivers/video/fbdev/i740fb.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/i740fb.c b/drivers/video/fbdev/i740fb.c
index 3860b137b86a..61c022b8d5de 100644
--- a/drivers/video/fbdev/i740fb.c
+++ b/drivers/video/fbdev/i740fb.c
@@ -31,6 +31,7 @@
 
 #include "i740_reg.h"
 
+static char *mode_option_buf;
 static char *mode_option;
 static int mtrr = 1;
 
@@ -1273,8 +1274,11 @@ static int  __init i740fb_setup(char *options)
 			continue;
 		else if (!strncmp(opt, "mtrr:", 5))
 			mtrr = simple_strtoul(opt + 5, NULL, 0);
-		else
-			mode_option = opt;
+		else {
+			kfree(mode_option_buf);
+			mode_option_buf = kstrdup(opt, GFP_KERNEL); // ignore errors
+			mode_option = mode_option_buf;
+		}
 	}
 
 	return 0;
@@ -1302,6 +1306,7 @@ static int __init i740fb_init(void)
 static void __exit i740fb_exit(void)
 {
 	pci_unregister_driver(&i740fb_driver);
+	kfree(mode_option_buf);
 }
 
 module_init(i740fb_init);
-- 
2.39.2