[openwrt/openwrt] kernel: mtdsplit_uimage: return 0 if not fatal

[LEDE Commits]

hauke pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/a51359aafde18b7e809842b4b4c31c78f5fa0c51

commit a51359aafde18b7e809842b4b4c31c78f5fa0c51
Author: Markus Stockhausen <markus.stockhausen at gmx.de>
AuthorDate: Tue Jun 17 05:21:40 2025 -0400

    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 at gmx.de>
    Link: https://github.com/openwrt/openwrt/pull/19163
    Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
---
 target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_uimage.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

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 1962cd8f2b..0d96854900 100644
--- 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;
 		}