diff options
| author | Ricardo Salveti <ricardo@foundries.io> | 2021-09-26 21:36:04 +0300 |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2021-10-12 16:49:21 -0400 |
| commit | 41130eb8937e43b2307fb67ebb60f0190fc01438 (patch) | |
| tree | b5e6473d4c10c563ef3659b55968311a8737723c /fs | |
| parent | 0892a7e5fa5ce38f58e0e6636ae56c6f60c080e0 (diff) | |
fs: fat: check for buffer size before reading blocks
This patch optimizes the commit mentioned below by avoiding running
a set of commands which are useless in the case when
size < mydata->sect_size and sect_count would be 0.
Fixes: 5b3ddb17ba ("fs/fat/fat.c: Do not perform zero block reads if there are no blocks left")
Signed-off-by: Ricardo Salveti <ricardo@foundries.io>
Co-developed-by: Oleksandr Suvorov <oleksandr.suvorov@foundries.io>
Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov@foundries.io>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/fat/fat.c | 23 |
1 files changed, 10 insertions, 13 deletions
diff --git a/fs/fat/fat.c b/fs/fat/fat.c index 7021138b98..65f77c4f75 100644 --- a/fs/fat/fat.c +++ b/fs/fat/fat.c @@ -275,22 +275,19 @@ get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size) buffer += mydata->sect_size; size -= mydata->sect_size; } - } else { - __u32 idx; - - idx = size / mydata->sect_size; - if (idx == 0) - ret = 0; - else - ret = disk_read(startsect, idx, buffer); - if (ret != idx) { + } else if (size >= mydata->sect_size) { + __u32 bytes_read; + __u32 sect_count = size / mydata->sect_size; + + ret = disk_read(startsect, sect_count, buffer); + if (ret != sect_count) { debug("Error reading data (got %d)\n", ret); return -1; } - startsect += idx; - idx *= mydata->sect_size; - buffer += idx; - size -= idx; + bytes_read = sect_count * mydata->sect_size; + startsect += sect_count; + buffer += bytes_read; + size -= bytes_read; } if (size) { ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size); |