fastboot: Fix blk_dwrite error checking

blk_dwrite() returns the number of blocks written.
The code was only checking if the return value was different
than 0. Hence, partial writes were considered successful.
Fix blk_dwrite error handling by checking that all blocks
are written.

Signed-off-by: Francois Berder <fberder@outlook.fr>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
Link: https://patch.msgid.link/BESP194MB2805BBD03E7C92727F116585DA0D2@BESP194MB2805.EURP194.PROD.OUTLOOK.COM
Signed-off-by: Mattijs Korpershoek <mkorpershoek@kernel.org>

diff --git a/drivers/fastboot/fb_mmc.c b/drivers/fastboot/fb_mmc.c
index 11d9c8e84602c7434733c060b84c91c38772ac9f..9bc782ccd0220a9f2564ef83fc9a9cf0bdcbab81 100644 (file)
--- a/drivers/fastboot/fb_mmc.c
+++ b/drivers/fastboot/fb_mmc.c
@@ -263,7 +263,7 @@ static int fb_mmc_update_zimage(struct blk_desc *dev_desc,
        /* Write new kernel size to boot image header */
        hdr->kernel_size = download_bytes;
        res = blk_dwrite(dev_desc, info.start, hdr_sectors, (void *)hdr);
-       if (res == 0) {
+       if (res != hdr_sectors) {
                pr_err("cannot writeback boot image header\n");
                fastboot_fail("cannot write back boot image header", response);
                return -1;
@@ -275,7 +275,7 @@ static int fb_mmc_update_zimage(struct blk_desc *dev_desc,
                                      sectors_per_page;
        res = blk_dwrite(dev_desc, kernel_sector_start, kernel_sectors,
                         download_buffer);
-       if (res == 0) {
+       if (res != kernel_sectors) {
                pr_err("cannot write new kernel\n");
                fastboot_fail("cannot write new kernel", response);
                return -1;
@@ -287,7 +287,7 @@ static int fb_mmc_update_zimage(struct blk_desc *dev_desc,
                                             sectors_per_page;
        res = blk_dwrite(dev_desc, ramdisk_sector_start, ramdisk_sectors,
                         ramdisk_buffer);
-       if (res == 0) {
+       if (res != ramdisk_sectors) {
                pr_err("cannot write back original ramdisk\n");
                fastboot_fail("cannot write back original ramdisk", response);
                return -1;