[PATCH] block: fix an address space warning in blk-map.c

From: Namhyung Kim
Date: Tue Sep 14 2010 - 11:42:59 EST


Change type of 2nd parameter of blk_rq_aligned() into unsigned long
and remove unnecessary casting. Now we can call it with 'uaddr'
instead of 'ubuf' in __blk_rq_map_user() so that it can remove
following warnings from sparse:

block/blk-map.c:57:31: warning: incorrect type in argument 2 (different address spaces)
block/blk-map.c:57:31: expected void *addr
block/blk-map.c:57:31: got void [noderef] <asn:1>*ubuf

However blk_rq_map_kern() needs one more local variable to handle it.

Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxx>
---
block/blk-map.c | 5 +++--
include/linux/blkdev.h | 4 ++--
2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/block/blk-map.c b/block/blk-map.c
index c65d759..ac0f7d4 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -54,7 +54,7 @@ static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
* direct dma. else, set up kernel bounce buffers
*/
uaddr = (unsigned long) ubuf;
- if (blk_rq_aligned(q, ubuf, len) && !map_data)
+ if (blk_rq_aligned(q, uaddr, len) && !map_data)
bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask);
else
bio = bio_copy_user(q, map_data, uaddr, len, reading, gfp_mask);
@@ -288,6 +288,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
unsigned int len, gfp_t gfp_mask)
{
int reading = rq_data_dir(rq) == READ;
+ unsigned long addr = (unsigned long) kbuf;
int do_copy = 0;
struct bio *bio;
int ret;
@@ -297,7 +298,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
if (!len || !kbuf)
return -EINVAL;

- do_copy = !blk_rq_aligned(q, kbuf, len) || object_is_on_stack(kbuf);
+ do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
if (do_copy)
bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
else
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 2c54906..71d7c9c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1093,11 +1093,11 @@ static inline int queue_dma_alignment(struct request_queue *q)
return q ? q->dma_alignment : 511;
}

-static inline int blk_rq_aligned(struct request_queue *q, void *addr,
+static inline int blk_rq_aligned(struct request_queue *q, unsigned long addr,
unsigned int len)
{
unsigned int alignment = queue_dma_alignment(q) | q->dma_pad_mask;
- return !((unsigned long)addr & alignment) && !(len & alignment);
+ return !(addr & alignment) && !(len & alignment);
}

/* assumes size > 256 */
--
1.7.2.2

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