Hi,
It is very common that FAT code is using following pattern: if (disk_{read|write}() < 0) return -1;
Up till now the above code was dead, since disk_{read|write) could only return value >= 0. As a result some errors from medium layer (i.e. eMMC/SD) were not caught.
The above behavior was caused by block_{read|write|erase} declared at struct block_dev_desc (@part.h). It returns unsigned long, where 0 indicates error and > 0 indicates that medium operation was correct.
This patch as error regards 0 returned from block_{read|write|erase} when nr_blocks is grater than zero. Read/Write operation with nr_blocks=0 should return 0 and hence is not considered as an error.
Signed-off-by: Lukasz Majewski l.majewski@samsung.com
Are there any more questions regarding this patch? I'd be more than happy if it would be added to v2015.10 :-).
Test HW: Odroid XU3 - Exynos 5433
fs/fat/fat.c | 11 +++++++++-- fs/fat/fat_write.c | 11 +++++++++-- 2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/fs/fat/fat.c b/fs/fat/fat.c index bccc3e3..d743014 100644 --- a/fs/fat/fat.c +++ b/fs/fat/fat.c @@ -45,11 +45,18 @@ static disk_partition_t cur_part_info;
static int disk_read(__u32 block, __u32 nr_blocks, void *buf) {
- ulong ret;
- if (!cur_dev || !cur_dev->block_read) return -1;
- return cur_dev->block_read(cur_dev->dev,
cur_part_info.start + block, nr_blocks, buf);
- ret = cur_dev->block_read(cur_dev->dev,
cur_part_info.start + block,nr_blocks, buf); +
- if (nr_blocks && ret == 0)
return -1;- return ret;
}
int fat_set_blk_dev(block_dev_desc_t *dev_desc, disk_partition_t *info) diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c index 98b88ad..adb6940 100644 --- a/fs/fat/fat_write.c +++ b/fs/fat/fat_write.c @@ -30,6 +30,8 @@ static void uppercase(char *str, int len) static int total_sector; static int disk_write(__u32 block, __u32 nr_blocks, void *buf) {
- ulong ret;
- if (!cur_dev || !cur_dev->block_write) return -1;
@@ -39,8 +41,13 @@ static int disk_write(__u32 block, __u32 nr_blocks, void *buf) return -1; }
- return cur_dev->block_write(cur_dev->dev,
cur_part_info.start + block,nr_blocks, buf);
- ret = cur_dev->block_write(cur_dev->dev,
cur_part_info.start + block,nr_blocks, buf);- if (nr_blocks && ret == 0)
return -1;- return ret;
}
/*