param: simple locking for sysfs-writable charp parameters
Since the writing to sysfs can free the old one, we need to block that
when we access the charp variables.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Dan Williams <dcbw@redhat.com>
Cc: John W. Linville <linville@tuxdriver.com>
Cc: Jing Huang <huangj@brocade.com>
Cc: James E.J. Bottomley <James.Bottomley@suse.de>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: libertas-dev@lists.infradead.org
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: linux-usb@vger.kernel.org
diff --git a/drivers/video/vt8623fb.c b/drivers/video/vt8623fb.c
index d31dc96..85d76ec 100644
--- a/drivers/video/vt8623fb.c
+++ b/drivers/video/vt8623fb.c
@@ -726,7 +726,9 @@
/* Prepare startup mode */
+ kparam_block_sysfs_write(mode_option);
rc = fb_find_mode(&(info->var), info, mode_option, NULL, 0, NULL, 8);
+ kparam_unblock_sysfs_write(mode_option);
if (! ((rc == 1) || (rc == 2))) {
rc = -EINVAL;
dev_err(info->device, "mode %s not found\n", mode_option);