[PATCH] Fixup blk_rq_unmap_user() API
The blk_rq_unmap_user() API is not very nice. It expects the caller to
know that rq->bio has to be reset to the original bio, and it will
silently do nothing if that is not done. Instead make it explicit that
we need to pass in the first bio, by expecting a bio argument.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index a66ec30..e07c079 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -2405,6 +2405,7 @@
unsigned long len)
{
unsigned long bytes_read = 0;
+ struct bio *bio = NULL;
int ret;
if (len > (q->max_hw_sectors << 9))
@@ -2431,6 +2432,8 @@
ret = __blk_rq_map_user(q, rq, ubuf, map_len);
if (ret < 0)
goto unmap_rq;
+ if (!bio)
+ bio = rq->bio;
bytes_read += ret;
ubuf += ret;
}
@@ -2438,7 +2441,7 @@
rq->buffer = rq->data = NULL;
return 0;
unmap_rq:
- blk_rq_unmap_user(rq);
+ blk_rq_unmap_user(bio);
return ret;
}
@@ -2495,29 +2498,30 @@
/**
* blk_rq_unmap_user - unmap a request with user data
- * @rq: rq to be unmapped
+ * @bio: start of bio list
*
* Description:
- * Unmap a rq previously mapped by blk_rq_map_user().
- * rq->bio must be set to the original head of the request.
+ * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
+ * supply the original rq->bio from the blk_rq_map_user() return, since
+ * the io completion may have changed rq->bio.
*/
-int blk_rq_unmap_user(struct request *rq)
+int blk_rq_unmap_user(struct bio *bio)
{
- struct bio *bio, *mapped_bio;
+ struct bio *mapped_bio;
int ret = 0, ret2;
- while ((bio = rq->bio)) {
- if (bio_flagged(bio, BIO_BOUNCED))
+ while (bio) {
+ mapped_bio = bio;
+ if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
mapped_bio = bio->bi_private;
- else
- mapped_bio = bio;
ret2 = __blk_rq_unmap_user(mapped_bio);
if (ret2 && !ret)
ret = ret2;
- rq->bio = bio->bi_next;
- bio_put(bio);
+ mapped_bio = bio;
+ bio = bio->bi_next;
+ bio_put(mapped_bio);
}
return ret;
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index f322b6a..2528a0c 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -333,8 +333,7 @@
hdr->sb_len_wr = len;
}
- rq->bio = bio;
- if (blk_rq_unmap_user(rq))
+ if (blk_rq_unmap_user(bio))
ret = -EFAULT;
/* may not have succeeded, but output values written to control
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index e4a2f8f..66d028d 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2139,8 +2139,7 @@
cdi->last_sense = s->sense_key;
}
- rq->bio = bio;
- if (blk_rq_unmap_user(rq))
+ if (blk_rq_unmap_user(bio))
ret = -EFAULT;
if (ret)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0fa3301..36a6eac 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -672,7 +672,7 @@
extern void blk_run_queue(request_queue_t *);
extern void blk_start_queueing(request_queue_t *);
extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned long);
-extern int blk_rq_unmap_user(struct request *);
+extern int blk_rq_unmap_user(struct bio *);
extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, gfp_t);
extern int blk_rq_map_user_iov(request_queue_t *, struct request *,
struct sg_iovec *, int, unsigned int);