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block: use blk_rq_map_user_iov to implement blk_rq_map_user
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Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Ming Lei <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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@axboe
Christoph Hellwig authored and axboe committed Feb 5, 2015
1 parent 42d2683 commit ddad8dd
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Showing 3 changed files with 14 additions and 180 deletions.
53 changes: 1 addition & 52 deletions block/bio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1102,7 +1102,7 @@ static int __bio_copy_iov(struct bio *bio, const struct sg_iovec *iov, int iov_c
* bio_uncopy_user - finish previously mapped bio
* @bio: bio being terminated
*
* Free pages allocated from bio_copy_user() and write back data
* Free pages allocated from bio_copy_user_iov() and write back data
* to user space in case of a read.
*/
int bio_uncopy_user(struct bio *bio)
Expand Down Expand Up @@ -1256,32 +1256,6 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
return ERR_PTR(ret);
}

/**
* bio_copy_user - copy user data to bio
* @q: destination block queue
* @map_data: pointer to the rq_map_data holding pages (if necessary)
* @uaddr: start of user address
* @len: length in bytes
* @write_to_vm: bool indicating writing to pages or not
* @gfp_mask: memory allocation flags
*
* Prepares and returns a bio for indirect user io, bouncing data
* to/from kernel pages as necessary. Must be paired with
* call bio_uncopy_user() on io completion.
*/
struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data,
unsigned long uaddr, unsigned int len,
int write_to_vm, gfp_t gfp_mask)
{
struct sg_iovec iov;

iov.iov_base = (void __user *)uaddr;
iov.iov_len = len;

return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask);
}
EXPORT_SYMBOL(bio_copy_user);

static struct bio *__bio_map_user_iov(struct request_queue *q,
struct block_device *bdev,
const struct sg_iovec *iov, int iov_count,
Expand Down Expand Up @@ -1394,31 +1368,6 @@ static struct bio *__bio_map_user_iov(struct request_queue *q,
return ERR_PTR(ret);
}

/**
* bio_map_user - map user address into bio
* @q: the struct request_queue for the bio
* @bdev: destination block device
* @uaddr: start of user address
* @len: length in bytes
* @write_to_vm: bool indicating writing to pages or not
* @gfp_mask: memory allocation flags
*
* Map the user space address into a bio suitable for io to a block
* device. Returns an error pointer in case of error.
*/
struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev,
unsigned long uaddr, unsigned int len, int write_to_vm,
gfp_t gfp_mask)
{
struct sg_iovec iov;

iov.iov_base = (void __user *)uaddr;
iov.iov_len = len;

return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask);
}
EXPORT_SYMBOL(bio_map_user);

/**
* bio_map_user_iov - map user sg_iovec table into bio
* @q: the struct request_queue for the bio
Expand Down
137 changes: 13 additions & 124 deletions block/blk-map.c
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Original file line number Diff line number Diff line change
Expand Up @@ -39,130 +39,6 @@ static int __blk_rq_unmap_user(struct bio *bio)
return ret;
}

static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
struct rq_map_data *map_data, void __user *ubuf,
unsigned int len, gfp_t gfp_mask)
{
unsigned long uaddr;
struct bio *bio, *orig_bio;
int reading, ret;

reading = rq_data_dir(rq) == READ;

/*
* if alignment requirement is satisfied, map in user pages for
* direct dma. else, set up kernel bounce buffers
*/
uaddr = (unsigned long) ubuf;
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);

if (IS_ERR(bio))
return PTR_ERR(bio);

if (map_data && map_data->null_mapped)
bio->bi_flags |= (1 << BIO_NULL_MAPPED);

orig_bio = bio;
blk_queue_bounce(q, &bio);

/*
* We link the bounce buffer in and could have to traverse it
* later so we have to get a ref to prevent it from being freed
*/
bio_get(bio);

ret = blk_rq_append_bio(q, rq, bio);
if (!ret)
return bio->bi_iter.bi_size;

/* if it was boucned we must call the end io function */
bio_endio(bio, 0);
__blk_rq_unmap_user(orig_bio);
bio_put(bio);
return ret;
}

/**
* 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
*
* Description:
* Data will be mapped directly for zero copy I/O, if possible. Otherwise
* a kernel bounce buffer is used.
*
* A matching blk_rq_unmap_user() must be issued at the end of I/O, while
* still in process context.
*
* Note: The mapped bio may need to be bounced through blk_queue_bounce()
* before being submitted to the device, as pages mapped may be out of
* reach. It's the callers responsibility to make sure this happens. The
* original bio must be passed back in to blk_rq_unmap_user() for proper
* unmapping.
*/
int blk_rq_map_user(struct request_queue *q, struct request *rq,
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;
int ret;

if (len > (queue_max_hw_sectors(q) << 9))
return -EINVAL;
if (!len)
return -EINVAL;

if (!ubuf && (!map_data || !map_data->null_mapped))
return -EINVAL;

while (bytes_read != len) {
unsigned long map_len, end, start;

map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
>> PAGE_SHIFT;
start = (unsigned long)ubuf >> PAGE_SHIFT;

/*
* A bad offset could cause us to require BIO_MAX_PAGES + 1
* pages. If this happens we just lower the requested
* mapping len by a page so that we can fit
*/
if (end - start > BIO_MAX_PAGES)
map_len -= PAGE_SIZE;

ret = __blk_rq_map_user(q, rq, map_data, ubuf, map_len,
gfp_mask);
if (ret < 0)
goto unmap_rq;
if (!bio)
bio = rq->bio;
bytes_read += ret;
ubuf += ret;

if (map_data)
map_data->offset += ret;
}

if (!bio_flagged(bio, BIO_USER_MAPPED))
rq->cmd_flags |= REQ_COPY_USER;

return 0;
unmap_rq:
blk_rq_unmap_user(bio);
rq->bio = NULL;
return ret;
}
EXPORT_SYMBOL(blk_rq_map_user);

/**
* 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
Expand Down Expand Up @@ -241,6 +117,19 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
}
EXPORT_SYMBOL(blk_rq_map_user_iov);

int blk_rq_map_user(struct request_queue *q, struct request *rq,
struct rq_map_data *map_data, void __user *ubuf,
unsigned long len, gfp_t gfp_mask)
{
struct sg_iovec iov;

iov.iov_base = (void __user *)ubuf;
iov.iov_len = len;

return blk_rq_map_user_iov(q, rq, map_data, &iov, 1, len, gfp_mask);
}
EXPORT_SYMBOL(blk_rq_map_user);

/**
* blk_rq_unmap_user - unmap a request with user data
* @bio: start of bio list
Expand Down
4 changes: 0 additions & 4 deletions include/linux/bio.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -428,8 +428,6 @@ extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
unsigned int, unsigned int);
extern int bio_get_nr_vecs(struct block_device *);
extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
unsigned long, unsigned int, int, gfp_t);
struct sg_iovec;
struct rq_map_data;
extern struct bio *bio_map_user_iov(struct request_queue *,
Expand Down Expand Up @@ -462,8 +460,6 @@ static inline void bio_flush_dcache_pages(struct bio *bi)
extern void bio_copy_data(struct bio *dst, struct bio *src);
extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);

extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
unsigned long, unsigned int, int, gfp_t);
extern struct bio *bio_copy_user_iov(struct request_queue *,
struct rq_map_data *,
const struct sg_iovec *,
Expand Down

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