[U-Boot] [PATCH] fs: fat: don't call disk_write with zero sector num

[Josh Wu]

In the set_cluster() function, it will convert the buffer size to sector
numbers. Then call disk_write() to write by sector.
For remaining buffer, the size is less than a sector, call disk_write()
again to write them in one sector.

But if the total buffer size is less then one sector, the original code
will call disk_write() with zero sector number. It is unnecessary.
So this patch fix this. Now it will not call disk_write() if total buffer size
is less than one sector.

Signed-off-by: Josh Wu <josh.wu at atmel.com>
---
 fs/fat/fat_write.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
index fd07240..a05327c 100644
--- a/fs/fat/fat_write.c
+++ b/fs/fat/fat_write.c
@@ -568,9 +568,11 @@ set_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer,
 
 	debug("clustnum: %d, startsect: %d\n", clustnum, startsect);
 
-	if (disk_write(startsect, size / mydata->sect_size, buffer) < 0) {
-		debug("Error writing data\n");
-		return -1;
+	if ((size / mydata->sect_size) > 0) {
+		if (disk_write(startsect, size / mydata->sect_size, buffer) < 0) {
+			debug("Error writing data\n");
+			return -1;
+		}
 	}
 
 	if (size % mydata->sect_size) {
-- 
1.7.9.5