[mirror_ubuntu-artful-kernel.git] / block / blk-map.c

/*
 * Functions related to mapping data to requests
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <scsi/sg.h>		/* for struct sg_iovec */

#include "blk.h"

int blk_rq_append_bio(struct request_queue *q, struct request *rq,
		      struct bio *bio)
{
	if (!rq->bio)
		blk_rq_bio_prep(q, rq, bio);
	else if (!ll_back_merge_fn(q, rq, bio))
		return -EINVAL;
	else {
		rq->biotail->bi_next = bio;
		rq->biotail = bio;

		rq->__data_len += bio->bi_size;
	}
	return 0;
}

static int __blk_rq_unmap_user(struct bio *bio)
{
	int ret = 0;

	if (bio) {
		if (bio_flagged(bio, BIO_USER_MAPPED))
			bio_unmap_user(bio);
		else
			ret = bio_uncopy_user(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_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;

	rq->buffer = NULL;
	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
 * @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
 * @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_iov(struct request_queue *q, struct request *rq,
			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;
	int unaligned = 0;

	if (!iov || iov_count <= 0)
		return -EINVAL;

	for (i = 0; i < iov_count; i++) {
		unsigned long uaddr = (unsigned long)iov[i].iov_base;

		if (uaddr & queue_dma_alignment(q)) {
			unaligned = 1;
			break;
		}
		if (!iov[i].iov_len)
			return -EINVAL;
	}

	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);

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

	if (bio->bi_size != len) {
		/*
		 * Grab an extra reference to this bio, as bio_unmap_user()
		 * expects to be able to drop it twice as it happens on the
		 * normal IO completion path
		 */
		bio_get(bio);
		bio_endio(bio, 0);
		__blk_rq_unmap_user(bio);
		return -EINVAL;
	}

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

	blk_queue_bounce(q, &bio);
	bio_get(bio);
	blk_rq_bio_prep(q, rq, bio);
	rq->buffer = NULL;
	return 0;
}
EXPORT_SYMBOL(blk_rq_map_user_iov);

/**
 * blk_rq_unmap_user - unmap a request with user data
 * @bio:	       start of bio list
 *
 * Description:
 *    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 I/O completion may have changed rq->bio.
 */
int blk_rq_unmap_user(struct bio *bio)
{
	struct bio *mapped_bio;
	int ret = 0, ret2;

	while (bio) {
		mapped_bio = bio;
		if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
			mapped_bio = bio->bi_private;

		ret2 = __blk_rq_unmap_user(mapped_bio);
		if (ret2 && !ret)
			ret = ret2;

		mapped_bio = bio;
		bio = bio->bi_next;
		bio_put(mapped_bio);
	}

	return ret;
}
EXPORT_SYMBOL(blk_rq_unmap_user);

/**
 * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage
 * @q:		request queue where request should be inserted
 * @rq:		request to fill
 * @kbuf:	the kernel buffer
 * @len:	length of user data
 * @gfp_mask:	memory allocation flags
 *
 * Description:
 *    Data will be mapped directly if possible. Otherwise a bounce
 *    buffer is used. Can be called multple times to append multple
 *    buffers.
 */
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;

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

	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
		bio = bio_map_kern(q, kbuf, len, gfp_mask);

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

	if (rq_data_dir(rq) == WRITE)
		bio->bi_rw |= REQ_WRITE;

	if (do_copy)
		rq->cmd_flags |= REQ_COPY_USER;

	ret = blk_rq_append_bio(q, rq, bio);
	if (unlikely(ret)) {
		/* request is too big */
		bio_put(bio);
		return ret;
	}

	blk_queue_bounce(q, &rq->bio);
	rq->buffer = NULL;
	return 0;
}
EXPORT_SYMBOL(blk_rq_map_kern);
Commit	Line	Data
86db1e29 JA	1	/*
	2	* Functions related to mapping data to requests
	3	*/
	4	#include <linux/kernel.h>
	5	#include <linux/module.h>
	6	#include <linux/bio.h>
	7	#include <linux/blkdev.h>
afdc1a78	8	#include <scsi/sg.h> /* for struct sg_iovec */
86db1e29 JA	9
	10	#include "blk.h"
	11
	12	int blk_rq_append_bio(struct request_queue q, struct request rq,
	13	struct bio *bio)
	14	{
	15	if (!rq->bio)
	16	blk_rq_bio_prep(q, rq, bio);
	17	else if (!ll_back_merge_fn(q, rq, bio))
	18	return -EINVAL;
	19	else {
	20	rq->biotail->bi_next = bio;
	21	rq->biotail = bio;
	22
a2dec7b3	23	rq->__data_len += bio->bi_size;
86db1e29 JA	24	}
	25	return 0;
	26	}
86db1e29 JA	27
	28	static int __blk_rq_unmap_user(struct bio *bio)
	29	{
	30	int ret = 0;
	31
	32	if (bio) {
	33	if (bio_flagged(bio, BIO_USER_MAPPED))
	34	bio_unmap_user(bio);
	35	else
	36	ret = bio_uncopy_user(bio);
	37	}
	38
	39	return ret;
	40	}
	41
	42	static int __blk_rq_map_user(struct request_queue q, struct request rq,
152e283f	43	struct rq_map_data map_data, void __user ubuf,
97ae77a1	44	unsigned int len, gfp_t gfp_mask)
86db1e29 JA	45	{
	46	unsigned long uaddr;
	47	struct bio bio, orig_bio;
	48	int reading, ret;
	49
	50	reading = rq_data_dir(rq) == READ;
	51
	52	/*
	53	* if alignment requirement is satisfied, map in user pages for
	54	* direct dma. else, set up kernel bounce buffers
	55	*/
	56	uaddr = (unsigned long) ubuf;
14417799	57	if (blk_rq_aligned(q, uaddr, len) && !map_data)
a3bce90e	58	bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask);
86db1e29	59	else
152e283f	60	bio = bio_copy_user(q, map_data, uaddr, len, reading, gfp_mask);
86db1e29 JA	61
	62	if (IS_ERR(bio))
	63	return PTR_ERR(bio);
	64
97ae77a1	65	if (map_data && map_data->null_mapped)
81882766 FT	66	bio->bi_flags \|= (1 << BIO_NULL_MAPPED);
81882766 FT	67
86db1e29 JA	68	orig_bio = bio;
	69	blk_queue_bounce(q, &bio);
	70
	71	/*
	72	* We link the bounce buffer in and could have to traverse it
	73	* later so we have to get a ref to prevent it from being freed
	74	*/
	75	bio_get(bio);
	76
	77	ret = blk_rq_append_bio(q, rq, bio);
	78	if (!ret)
	79	return bio->bi_size;
	80
	81	/* if it was boucned we must call the end io function */
	82	bio_endio(bio, 0);
	83	__blk_rq_unmap_user(orig_bio);
	84	bio_put(bio);
	85	return ret;
	86	}
	87
	88	/**
710027a4	89	* blk_rq_map_user - map user data to a request, for REQ_TYPE_BLOCK_PC usage
86db1e29 JA	90	* @q: request queue where request should be inserted
86db1e29 JA	91	* @rq: request structure to fill
152e283f	92	* @map_data: pointer to the rq_map_data holding pages (if necessary)
86db1e29 JA	93	* @ubuf: the user buffer
86db1e29 JA	94	* @len: length of user data
a3bce90e	95	* @gfp_mask: memory allocation flags
86db1e29 JA	96	*
86db1e29 JA	97	* Description:
710027a4	98	* Data will be mapped directly for zero copy I/O, if possible. Otherwise
86db1e29 JA	99	* a kernel bounce buffer is used.
86db1e29 JA	100	*
710027a4	101	* A matching blk_rq_unmap_user() must be issued at the end of I/O, while
86db1e29 JA	102	* still in process context.
	103	*
	104	* Note: The mapped bio may need to be bounced through blk_queue_bounce()
	105	* before being submitted to the device, as pages mapped may be out of
	106	* reach. It's the callers responsibility to make sure this happens. The
	107	* original bio must be passed back in to blk_rq_unmap_user() for proper
	108	* unmapping.
	109	*/
	110	int blk_rq_map_user(struct request_queue q, struct request rq,
152e283f FT	111	struct rq_map_data map_data, void __user ubuf,
152e283f FT	112	unsigned long len, gfp_t gfp_mask)
86db1e29 JA	113	{
	114	unsigned long bytes_read = 0;
	115	struct bio *bio = NULL;
97ae77a1	116	int ret;
86db1e29	117
ae03bf63	118	if (len > (queue_max_hw_sectors(q) << 9))
86db1e29	119	return -EINVAL;
81882766	120	if (!len)
86db1e29	121	return -EINVAL;
97ae77a1 FT	122
	123	if (!ubuf && (!map_data \|\| !map_data->null_mapped))
	124	return -EINVAL;
86db1e29 JA	125
	126	while (bytes_read != len) {
	127	unsigned long map_len, end, start;
	128
	129	map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
	130	end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
	131	>> PAGE_SHIFT;
	132	start = (unsigned long)ubuf >> PAGE_SHIFT;
	133
	134	/*
	135	* A bad offset could cause us to require BIO_MAX_PAGES + 1
	136	* pages. If this happens we just lower the requested
	137	* mapping len by a page so that we can fit
	138	*/
	139	if (end - start > BIO_MAX_PAGES)
	140	map_len -= PAGE_SIZE;
	141
152e283f	142	ret = __blk_rq_map_user(q, rq, map_data, ubuf, map_len,
97ae77a1	143	gfp_mask);
86db1e29 JA	144	if (ret < 0)
	145	goto unmap_rq;
	146	if (!bio)
	147	bio = rq->bio;
	148	bytes_read += ret;
	149	ubuf += ret;
56c451f4 FT	150
	151	if (map_data)
	152	map_data->offset += ret;
86db1e29 JA	153	}
86db1e29 JA	154
f18573ab FT	155	if (!bio_flagged(bio, BIO_USER_MAPPED))
f18573ab FT	156	rq->cmd_flags \|= REQ_COPY_USER;
40b01b9b	157
731ec497	158	rq->buffer = NULL;
86db1e29 JA	159	return 0;
	160	unmap_rq:
	161	blk_rq_unmap_user(bio);
84e9e03c	162	rq->bio = NULL;
86db1e29 JA	163	return ret;
86db1e29 JA	164	}
86db1e29 JA	165	EXPORT_SYMBOL(blk_rq_map_user);
	166
	167	/**
710027a4	168	* blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage
86db1e29 JA	169	* @q: request queue where request should be inserted
86db1e29 JA	170	* @rq: request to map data to
152e283f	171	* @map_data: pointer to the rq_map_data holding pages (if necessary)
86db1e29 JA	172	* @iov: pointer to the iovec
	173	* @iov_count: number of elements in the iovec
	174	* @len: I/O byte count
a3bce90e	175	* @gfp_mask: memory allocation flags
86db1e29 JA	176	*
86db1e29 JA	177	* Description:
710027a4	178	* Data will be mapped directly for zero copy I/O, if possible. Otherwise
86db1e29 JA	179	* a kernel bounce buffer is used.
86db1e29 JA	180	*
710027a4	181	* A matching blk_rq_unmap_user() must be issued at the end of I/O, while
86db1e29 JA	182	* still in process context.
	183	*
	184	* Note: The mapped bio may need to be bounced through blk_queue_bounce()
	185	* before being submitted to the device, as pages mapped may be out of
	186	* reach. It's the callers responsibility to make sure this happens. The
	187	* original bio must be passed back in to blk_rq_unmap_user() for proper
	188	* unmapping.
	189	*/
	190	int blk_rq_map_user_iov(struct request_queue q, struct request rq,
152e283f FT	191	struct rq_map_data map_data, struct sg_iovec iov,
152e283f FT	192	int iov_count, unsigned int len, gfp_t gfp_mask)
86db1e29 JA	193	{
86db1e29 JA	194	struct bio *bio;
afdc1a78 FT	195	int i, read = rq_data_dir(rq) == READ;
afdc1a78 FT	196	int unaligned = 0;
86db1e29 JA	197
	198	if (!iov \|\| iov_count <= 0)
	199	return -EINVAL;
	200
afdc1a78 FT	201	for (i = 0; i < iov_count; i++) {
	202	unsigned long uaddr = (unsigned long)iov[i].iov_base;
	203
	204	if (uaddr & queue_dma_alignment(q)) {
	205	unaligned = 1;
	206	break;
	207	}
9284bcf4 JA	208	if (!iov[i].iov_len)
9284bcf4 JA	209	return -EINVAL;
afdc1a78 FT	210	}
afdc1a78 FT	211
152e283f FT	212	if (unaligned \|\| (q->dma_pad_mask & len) \|\| map_data)
	213	bio = bio_copy_user_iov(q, map_data, iov, iov_count, read,
	214	gfp_mask);
afdc1a78	215	else
a3bce90e	216	bio = bio_map_user_iov(q, NULL, iov, iov_count, read, gfp_mask);
afdc1a78	217
86db1e29 JA	218	if (IS_ERR(bio))
	219	return PTR_ERR(bio);
	220
	221	if (bio->bi_size != len) {
c26156b2 JA	222	/*
	223	* Grab an extra reference to this bio, as bio_unmap_user()
	224	* expects to be able to drop it twice as it happens on the
	225	* normal IO completion path
	226	*/
	227	bio_get(bio);
86db1e29	228	bio_endio(bio, 0);
53cc0b29	229	__blk_rq_unmap_user(bio);
86db1e29 JA	230	return -EINVAL;
	231	}
	232
f18573ab FT	233	if (!bio_flagged(bio, BIO_USER_MAPPED))
	234	rq->cmd_flags \|= REQ_COPY_USER;
	235
07359fc6	236	blk_queue_bounce(q, &bio);
86db1e29 JA	237	bio_get(bio);
86db1e29 JA	238	blk_rq_bio_prep(q, rq, bio);
731ec497	239	rq->buffer = NULL;
86db1e29 JA	240	return 0;
86db1e29 JA	241	}
152e283f	242	EXPORT_SYMBOL(blk_rq_map_user_iov);
86db1e29 JA	243
	244	/**
	245	* blk_rq_unmap_user - unmap a request with user data
	246	* @bio: start of bio list
	247	*
	248	* Description:
	249	* Unmap a rq previously mapped by blk_rq_map_user(). The caller must
	250	* supply the original rq->bio from the blk_rq_map_user() return, since
710027a4	251	* the I/O completion may have changed rq->bio.
86db1e29 JA	252	*/
	253	int blk_rq_unmap_user(struct bio *bio)
	254	{
	255	struct bio *mapped_bio;
	256	int ret = 0, ret2;
	257
	258	while (bio) {
	259	mapped_bio = bio;
	260	if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
	261	mapped_bio = bio->bi_private;
	262
	263	ret2 = __blk_rq_unmap_user(mapped_bio);
	264	if (ret2 && !ret)
	265	ret = ret2;
	266
	267	mapped_bio = bio;
	268	bio = bio->bi_next;
	269	bio_put(mapped_bio);
	270	}
	271
	272	return ret;
	273	}
86db1e29 JA	274	EXPORT_SYMBOL(blk_rq_unmap_user);
	275
	276	/**
710027a4	277	* blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage
86db1e29 JA	278	* @q: request queue where request should be inserted
	279	* @rq: request to fill
	280	* @kbuf: the kernel buffer
	281	* @len: length of user data
	282	* @gfp_mask: memory allocation flags
68154e90 FT	283	*
	284	* Description:
	285	* Data will be mapped directly if possible. Otherwise a bounce
3a5a3927 JB	286	* buffer is used. Can be called multple times to append multple
3a5a3927 JB	287	* buffers.
86db1e29 JA	288	*/
	289	int blk_rq_map_kern(struct request_queue q, struct request rq, void *kbuf,
	290	unsigned int len, gfp_t gfp_mask)
	291	{
68154e90	292	int reading = rq_data_dir(rq) == READ;
14417799	293	unsigned long addr = (unsigned long) kbuf;
68154e90	294	int do_copy = 0;
86db1e29	295	struct bio *bio;
3a5a3927	296	int ret;
86db1e29	297
ae03bf63	298	if (len > (queue_max_hw_sectors(q) << 9))
86db1e29 JA	299	return -EINVAL;
	300	if (!len \|\| !kbuf)
	301	return -EINVAL;
	302
14417799	303	do_copy = !blk_rq_aligned(q, addr, len) \|\| object_is_on_stack(kbuf);
68154e90 FT	304	if (do_copy)
	305	bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
	306	else
	307	bio = bio_map_kern(q, kbuf, len, gfp_mask);
	308
86db1e29 JA	309	if (IS_ERR(bio))
	310	return PTR_ERR(bio);
	311
	312	if (rq_data_dir(rq) == WRITE)
a45dc2d2	313	bio->bi_rw \|= REQ_WRITE;
86db1e29	314
68154e90 FT	315	if (do_copy)
	316	rq->cmd_flags \|= REQ_COPY_USER;
	317
3a5a3927 JB	318	ret = blk_rq_append_bio(q, rq, bio);
	319	if (unlikely(ret)) {
	320	/* request is too big */
	321	bio_put(bio);
	322	return ret;
	323	}
	324
86db1e29	325	blk_queue_bounce(q, &rq->bio);
731ec497	326	rq->buffer = NULL;
86db1e29 JA	327	return 0;
86db1e29 JA	328	}
86db1e29	329	EXPORT_SYMBOL(blk_rq_map_kern);