linux-kernel - [PATCH v2 015/101] fbdev/cirrusfb: Duplicate video-mode option string

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Message-Id: <20230309160201.5163-16-tzimmermann@suse.de>
Date:   Thu,  9 Mar 2023 17:00:35 +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 015/101] fbdev/cirrusfb: 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/cirrusfb.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/video/fbdev/cirrusfb.c b/drivers/video/fbdev/cirrusfb.c
index ba45e2147c52..85b9442031b3 100644
--- a/drivers/video/fbdev/cirrusfb.c
+++ b/drivers/video/fbdev/cirrusfb.c
@@ -367,6 +367,7 @@ struct cirrusfb_info {
 };
 
 static bool noaccel;
+static char *mode_option_buf;
 static char *mode_option = "640x480@60";
 
 /****************************************************************************/
@@ -2336,10 +2337,13 @@ static int __init cirrusfb_setup(char *options)
 
 		if (!strcmp(this_opt, "noaccel"))
 			noaccel = 1;
-		else if (!strncmp(this_opt, "mode:", 5))
-			mode_option = this_opt + 5;
-		else
-			mode_option = this_opt;
+		else {
+			if (!strncmp(this_opt, "mode:", 5))
+				this_opt += 5;
+			kfree(mode_option_buf);
+			mode_option_buf = kstrdup(this_opt, GFP_KERNEL); // ignore errors
+			mode_option = mode_option_buf;
+		}
 	}
 	return 0;
 }
@@ -2387,6 +2391,7 @@ static void __exit cirrusfb_exit(void)
 #ifdef CONFIG_ZORRO
 	zorro_unregister_driver(&cirrusfb_zorro_driver);
 #endif
+	kfree(mode_option_buf);
 }
 
 module_init(cirrusfb_init);
-- 
2.39.2