block: introduce struct rq_map_data to use reserved pages
This patch introduces struct rq_map_data to enable bio_copy_use_iov()
use reserved pages.
Currently, bio_copy_user_iov allocates bounce pages but
drivers/scsi/sg.c wants to allocate pages by itself and use
them. struct rq_map_data can be used to pass allocated pages to
bio_copy_user_iov.
The current users of bio_copy_user_iov simply passes NULL (they don't
want to use pre-allocated pages).
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Douglas Gilbert <dougg@torque.net>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blk-map.c b/block/blk-map.c
index ac21b73..dad6a29 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -41,8 +41,8 @@
}
static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
- void __user *ubuf, unsigned int len,
- gfp_t gfp_mask)
+ struct rq_map_data *map_data, void __user *ubuf,
+ unsigned int len, gfp_t gfp_mask)
{
unsigned long uaddr;
unsigned int alignment;
@@ -57,10 +57,10 @@
*/
uaddr = (unsigned long) ubuf;
alignment = queue_dma_alignment(q) | q->dma_pad_mask;
- if (!(uaddr & alignment) && !(len & alignment))
+ if (!(uaddr & alignment) && !(len & alignment) && !map_data)
bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask);
else
- bio = bio_copy_user(q, uaddr, len, reading, gfp_mask);
+ bio = bio_copy_user(q, map_data, uaddr, len, reading, gfp_mask);
if (IS_ERR(bio))
return PTR_ERR(bio);
@@ -89,6 +89,7 @@
* blk_rq_map_user - map user data to a request, for REQ_TYPE_BLOCK_PC usage
* @q: request queue where request should be inserted
* @rq: request structure to fill
+ * @map_data: pointer to the rq_map_data holding pages (if necessary)
* @ubuf: the user buffer
* @len: length of user data
* @gfp_mask: memory allocation flags
@@ -107,7 +108,8 @@
* unmapping.
*/
int blk_rq_map_user(struct request_queue *q, struct request *rq,
- void __user *ubuf, unsigned long len, gfp_t gfp_mask)
+ struct rq_map_data *map_data, void __user *ubuf,
+ unsigned long len, gfp_t gfp_mask)
{
unsigned long bytes_read = 0;
struct bio *bio = NULL;
@@ -134,7 +136,8 @@
if (end - start > BIO_MAX_PAGES)
map_len -= PAGE_SIZE;
- ret = __blk_rq_map_user(q, rq, ubuf, map_len, gfp_mask);
+ ret = __blk_rq_map_user(q, rq, map_data, ubuf, map_len,
+ gfp_mask);
if (ret < 0)
goto unmap_rq;
if (!bio)
@@ -159,6 +162,7 @@
* blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage
* @q: request queue where request should be inserted
* @rq: request to map data to
+ * @map_data: pointer to the rq_map_data holding pages (if necessary)
* @iov: pointer to the iovec
* @iov_count: number of elements in the iovec
* @len: I/O byte count
@@ -178,8 +182,8 @@
* unmapping.
*/
int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
- struct sg_iovec *iov, int iov_count, unsigned int len,
- gfp_t gfp_mask)
+ struct rq_map_data *map_data, struct sg_iovec *iov,
+ int iov_count, unsigned int len, gfp_t gfp_mask)
{
struct bio *bio;
int i, read = rq_data_dir(rq) == READ;
@@ -197,8 +201,9 @@
}
}
- if (unaligned || (q->dma_pad_mask & len))
- bio = bio_copy_user_iov(q, iov, iov_count, read, gfp_mask);
+ if (unaligned || (q->dma_pad_mask & len) || map_data)
+ bio = bio_copy_user_iov(q, map_data, iov, iov_count, read,
+ gfp_mask);
else
bio = bio_map_user_iov(q, NULL, iov, iov_count, read, gfp_mask);
@@ -220,6 +225,7 @@
rq->buffer = rq->data = NULL;
return 0;
}
+EXPORT_SYMBOL(blk_rq_map_user_iov);
/**
* blk_rq_unmap_user - unmap a request with user data
