openwrt/target/linux/generic/pending-4.14/490-ubi-auto-attach-mtd-device-named-ubi-or-data-on-boot.patch
Mathias Kresin edc2af2be9 kernel: improve ubi auto attach code readability
Move the put_mtd_device() called on multiple error conditions to a goto
label to use it later for more error conditions.

The early return on failed open of the mtd device and mismatching mtd
type allows to get rid of one level of indentation. By jumping to the
cleanup code, a refcount bug is fixed for the wrong flash type condition.

While at it, make clear that we only check for the UBI magic if the read
from flash was successful.

Signed-off-by: Mathias Kresin <dev@kresin.me>
(backported from fdf6760cda)
(rebased patches)
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
2018-12-18 09:50:47 +01:00

79 lines
2.0 KiB
Diff

From: Daniel Golle <daniel@makrotopia.org>
Subject: ubi: auto-attach mtd device named "ubi" or "data" on boot
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
drivers/mtd/ubi/build.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -1172,6 +1172,54 @@ static struct mtd_info * __init open_mtd
return mtd;
}
+/*
+ * This function tries attaching mtd partitions named either "ubi" or "data"
+ * during boot.
+ */
+static void __init ubi_auto_attach(void)
+{
+ int err;
+ struct mtd_info *mtd;
+ size_t len;
+ char magic[4];
+
+ /* try attaching mtd device named "ubi" or "data" */
+ mtd = open_mtd_device("ubi");
+ if (IS_ERR(mtd))
+ mtd = open_mtd_device("data");
+
+ if (IS_ERR(mtd))
+ return;
+
+ /* check for a valid ubi magic if read from flash was successful */
+ err = mtd_read(mtd, 0, 4, &len, (void *) magic);
+ if (!err && len == 4 && strncmp(magic, "UBI#", 4)) {
+ pr_err("UBI error: no valid UBI magic found inside mtd%d\n", mtd->index);
+ goto cleanup;
+ }
+
+ /* don't auto-add media types where UBI doesn't makes sense */
+ if (mtd->type != MTD_NANDFLASH &&
+ mtd->type != MTD_NORFLASH &&
+ mtd->type != MTD_DATAFLASH &&
+ mtd->type != MTD_MLCNANDFLASH)
+ goto cleanup;
+
+ mutex_lock(&ubi_devices_mutex);
+ pr_notice("UBI: auto-attach mtd%d\n", mtd->index);
+ err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO, 0, 0);
+ mutex_unlock(&ubi_devices_mutex);
+ if (err < 0) {
+ pr_err("UBI error: cannot attach mtd%d\n", mtd->index);
+ goto cleanup;
+ }
+
+ return;
+
+cleanup:
+ put_mtd_device(mtd);
+}
+
static int __init ubi_init(void)
{
int err, i, k;
@@ -1255,6 +1303,12 @@ static int __init ubi_init(void)
}
}
+ /* auto-attach mtd devices only if built-in to the kernel and no ubi.mtd
+ * parameter was given */
+ if (IS_ENABLED(CONFIG_MTD_ROOTFS_ROOT_DEV) &&
+ !ubi_is_module() && !mtd_devs)
+ ubi_auto_attach();
+
err = ubiblock_init();
if (err) {
pr_err("UBI error: block: cannot initialize, error %d\n", err);