kernel: mtdsplit_uimage: return 0 if not fatal

Introduced with Linux 6.7, in commit:
5c2f7727d437 ("mtd: mtdpart: check for subpartitions parsing result"),
when a parser returns an error, this will be passed up, and
consequently, all parent mtd partitions get torn down.

Adjust the mtdsplit_uimage driver to only return an error if there is a
critical problem in reading from the mtd device or allocating memory.
Otherwise return 0 to indicate that no partitions were found.
Also add logging to indicate what went wrong.

E.g. on Realtek devices that are booted for the first time through
initramfs with OpenWrt never installed before boot log will show

[    0.975518] Creating 7 MTD partitions on "spi0.0":
[    0.981062] 0x000000000000-0x0000000e0000 : "u-boot"
[    1.041320] 0x0000000e0000-0x0000000f0000 : "u-boot-env"
[    1.060683] 0x0000000f0000-0x000000100000 : "u-boot-env2"
[    1.080992] 0x000000100000-0x000000200000 : "jffs2-cfg"
[    1.100988] 0x000000200000-0x000000300000 : "jffs2-log"
[    1.120599] 0x000000300000-0x000000fe0000 : "firmware"
[    1.157426] mtdsplit_uimage: no rootfs after uImage in "firmware"
[    1.176456] mtdsplit_uimage: no rootfs after uImage in "firmware"
[    1.200262] 0x000000fe0000-0x000001000000 : "log"

Similar issues were fixed before with commit ade045084bd3f8696
("kernel: mtdsplit_minor: return 0 if not fatal") and
c78765213ecbe830204 ("kernel: mtdsplit_uimage: return 0 if not fatal")

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/19163
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

diff --git a/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_uimage.c b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_uimage.c
index 1962cd8f2bf770e5023b41ba29f2ca0bdd9c98f5..0d96854900309f792e02e5ec902c464192ae493b 100644 (file)
--- a/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_uimage.c
+++ b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_uimage.c
@@ -201,8 +201,8 @@ static int __mtdsplit_parse_uimage(struct mtd_info *master,
                ret = mtd_find_rootfs_from(master, uimage_offset + uimage_size,
                                           master->size, &rootfs_offset, &type);
                if (ret) {
-                       pr_debug("no rootfs after uImage in \"%s\"\n",
-                                master->name);
+                       pr_info("no rootfs after uImage in \"%s\"\n", master->name);
+                       ret = 0;
                        goto err_free_buf;
                }
 
@@ -215,8 +215,8 @@ static int __mtdsplit_parse_uimage(struct mtd_info *master,
                /* check rootfs presence at offset 0 */
                ret = mtd_check_rootfs_magic(master, 0, &type);
                if (ret) {
-                       pr_debug("no rootfs before uImage in \"%s\"\n",
-                                master->name);
+                       pr_info("no rootfs before uImage in \"%s\"\n", master->name);
+                       ret = 0;
                        goto err_free_buf;
                }