[PATCH] [MTD] mtdchar.c: ioctl always returns 0 as size written for ppc64

[David Scidmore]

"include/linux/mtd/mtd.h" declares "mtd_oob_ops.retlen" as size_t, which 
is 64 bits on targets with a 64 bit addressing. The MEMWRITEOOB ioctl 
calls copy_to_user() to write it back to "mtd_oob_buf.length", which is 
declared in "include/linux/mtd-abi.h" as uint32_t. Since powerpc is a 
big endian architecture, this only copies the upper 32 bits of the 
address, which is always 0.

Signed-off-by: David Scidmore <dscidmore at xes-inc.com>

------

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 22ed96c..bfc0958 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -483,6 +482,7 @@ static int mtd_ioctl(struct inode *inode, struct 
file *file,
     {
         struct mtd_oob_buf buf;
         struct mtd_oob_ops ops;
+            uint32_t retlen;
 
         if(!(file->f_mode & 2))
             return -EPERM;
@@ -522,8 +522,12 @@ static int mtd_ioctl(struct inode *inode, struct 
file *file,
         buf.start &= ~(mtd->oobsize - 1);
         ret = mtd->write_oob(mtd, buf.start, &ops);
 
-        if (copy_to_user(argp + sizeof(uint32_t), &ops.oobretlen,
-                 sizeof(uint32_t)))
+        if (ops.oobretlen > 0xFFFFFFFFU)
+            ret = -EOVERFLOW;
+        retlen = ops.oobretlen;
+        if (copy_to_user(&((struct mtd_oob_buf *)argp)->length,
+                 &retlen,
+                 sizeof(buf.length)))
             ret = -EFAULT;
 
         kfree(ops.oobbuf);


-- 
David Scidmore
Quality Manager
Extreme Engineering Solutions
608-833-1155 ext 101
www.xes-inc.com


-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: mtdchar.c.patch
Url: http://lists.infradead.org/pipermail/linux-mtd/attachments/20071211/baceedc9/attachment.pl