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

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/usb/atm/ueagle-atm.c b/drivers/usb/atm/ueagle-atm.c
index 5b3f555e01c9..ea071a5b6eee 100644
--- a/drivers/usb/atm/ueagle-atm.c
+++ b/drivers/usb/atm/ueagle-atm.c
@@ -1577,6 +1577,7 @@ static void cmvs_file_name(struct uea_softc *sc, char *const cmv_name, int ver)
         char file_arr[] = "CMVxy.bin";
         char *file;
 
+        kparam_block_sysfs_write(cmv_file);
         /* set proper name corresponding modem version and line type */
         if (cmv_file[sc->modem_index] == NULL) {
                 if (UEA_CHIP_VERSION(sc) == ADI930)
@@ -1595,6 +1596,7 @@ static void cmvs_file_name(struct uea_softc *sc, char *const cmv_name, int ver)
         strlcat(cmv_name, file, UEA_FW_NAME_MAX);
         if (ver == 2)
                 strlcat(cmv_name, ".v2", UEA_FW_NAME_MAX);
+        kparam_unblock_sysfs_write(cmv_file);
 }
 
 static int request_cmvs_old(struct uea_softc *sc,