From: Łukasz Majewski <l.majewski@samsung.com>
Date: Wed, 5 Dec 2012 08:06:37 +0000 (+0000)
Subject: fs:ext4:write: Add lldiv and do_div to perform 64-32 bits division
X-Git-Tag: v2013.01-rc2~77
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=32fc16d7e7a81816ce247b7cd70c94f3210a228b;p=kernel%2Fu-boot.git

fs:ext4:write: Add lldiv and do_div to perform 64-32 bits division

The ext4write code has been using direct calls to 64-32 division
(/ and %).

Officially supported u-boot toolchains (eldk-5.[12].x) generate calls
to __aeabi_uldivmod(), which is niether defined in the toolchain libs
nor u-boot source tree.

Due to that, when the ext4write command has been executed, "undefined
instruction" execption was generated (since the __aeabi_uldivmod()
is not provided).

To fix this error, lldiv() for division and do_div() for modulo have
been used.

Those two functions are recommended for performing 64-32 bit number
division in u-boot.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---

diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
index 06536ba..80b3b90 100644
--- a/fs/ext4/ext4fs.c
+++ b/fs/ext4/ext4fs.c
@@ -40,6 +40,7 @@
 #include <linux/stat.h>
 #include <linux/time.h>
 #include <asm/byteorder.h>
+#include <div64.h>
 #include "ext4_common.h"
 
 int ext4fs_symlinknest;
@@ -1051,8 +1052,8 @@ int ext4fs_write(const char *fname, unsigned char *buffer,
 	}
 	/* calucalate how many blocks required */
 	bytes_reqd_for_file = sizebytes;
-	blks_reqd_for_file = bytes_reqd_for_file / fs->blksz;
-	if (bytes_reqd_for_file % fs->blksz != 0) {
+	blks_reqd_for_file = lldiv(bytes_reqd_for_file, fs->blksz);
+	if (do_div(bytes_reqd_for_file, fs->blksz) != 0) {
 		blks_reqd_for_file++;
 		debug("total bytes for a file %u\n", blks_reqd_for_file);
 	}