[linux-2.6-block.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 "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->raw_data_len += bio->bi_size;
		rq->data_len += bio->bi_size;
	}
	return 0;
}
EXPORT_SYMBOL(blk_rq_append_bio);

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,
			     void __user *ubuf, unsigned int len)
{
	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 (!(uaddr & queue_dma_alignment(q)) &&
	    !(len & queue_dma_alignment(q)))
		bio = bio_map_user(q, NULL, uaddr, len, reading);
	else
		bio = bio_copy_user(q, uaddr, len, reading);

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

	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_BLOCK_PC usage
 * @q:		request queue where request should be inserted
 * @rq:		request structure to fill
 * @ubuf:	the user buffer
 * @len:	length of user data
 *
 * Description:
 *    Data will be mapped directly for zero copy io, if possible. Otherwise
 *    a kernel bounce buffer is used.
 *
 *    A matching blk_rq_unmap_user() must be issued at the end of io, 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,
		    void __user *ubuf, unsigned long len)
{
	unsigned long bytes_read = 0;
	struct bio *bio = NULL;
	int ret;

	if (len > (q->max_hw_sectors << 9))
		return -EINVAL;
	if (!len || !ubuf)
		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, ubuf, map_len);
		if (ret < 0)
			goto unmap_rq;
		if (!bio)
			bio = rq->bio;
		bytes_read += ret;
		ubuf += ret;
	}

	/*
	 * __blk_rq_map_user() copies the buffers if starting address
	 * or length isn't aligned.  As the copied buffer is always
	 * page aligned, we know that there's enough room for padding.
	 * Extend the last bio and update rq->data_len accordingly.
	 *
	 * On unmap, bio_uncopy_user() will use unmodified
	 * bio_map_data pointed to by bio->bi_private.
	 */
	if (len & queue_dma_alignment(q)) {
		unsigned int pad_len = (queue_dma_alignment(q) & ~len) + 1;
		struct bio *bio = rq->biotail;

		bio->bi_io_vec[bio->bi_vcnt - 1].bv_len += pad_len;
		bio->bi_size += pad_len;
		rq->data_len += pad_len;
	}

	rq->buffer = rq->data = 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_BLOCK_PC usage
 * @q:		request queue where request should be inserted
 * @rq:		request to map data to
 * @iov:	pointer to the iovec
 * @iov_count:	number of elements in the iovec
 * @len:	I/O byte count
 *
 * Description:
 *    Data will be mapped directly for zero copy io, if possible. Otherwise
 *    a kernel bounce buffer is used.
 *
 *    A matching blk_rq_unmap_user() must be issued at the end of io, 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 sg_iovec *iov, int iov_count, unsigned int len)
{
	struct bio *bio;

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

	/* we don't allow misaligned data like bio_map_user() does.  If the
	 * user is using sg, they're expected to know the alignment constraints
	 * and respect them accordingly */
	bio = bio_map_user_iov(q, NULL, iov, iov_count,
				rq_data_dir(rq) == READ);
	if (IS_ERR(bio))
		return PTR_ERR(bio);

	if (bio->bi_size != len) {
		bio_endio(bio, 0);
		bio_unmap_user(bio);
		return -EINVAL;
	}

	bio_get(bio);
	blk_rq_bio_prep(q, rq, bio);
	rq->buffer = rq->data = 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 io 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_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
 */
int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
		    unsigned int len, gfp_t gfp_mask)
{
	struct bio *bio;

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

	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 |= (1 << BIO_RW);

	blk_rq_bio_prep(q, rq, bio);
	blk_queue_bounce(q, &rq->bio);
	rq->buffer = rq->data = 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>
	8
	9	#include "blk.h"
	10
	11	int blk_rq_append_bio(struct request_queue q, struct request rq,
	12	struct bio *bio)
	13	{
	14	if (!rq->bio)
	15	blk_rq_bio_prep(q, rq, bio);
	16	else if (!ll_back_merge_fn(q, rq, bio))
	17	return -EINVAL;
	18	else {
	19	rq->biotail->bi_next = bio;
	20	rq->biotail = bio;
	21
6b00769f	22	rq->raw_data_len += bio->bi_size;
86db1e29 JA	23	rq->data_len += bio->bi_size;
	24	}
	25	return 0;
	26	}
	27	EXPORT_SYMBOL(blk_rq_append_bio);
	28
	29	static int __blk_rq_unmap_user(struct bio *bio)
	30	{
	31	int ret = 0;
	32
	33	if (bio) {
	34	if (bio_flagged(bio, BIO_USER_MAPPED))
	35	bio_unmap_user(bio);
	36	else
	37	ret = bio_uncopy_user(bio);
	38	}
	39
	40	return ret;
	41	}
	42
	43	static int __blk_rq_map_user(struct request_queue q, struct request rq,
	44	void __user *ubuf, unsigned int len)
	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;
6728cb0e JA	57	if (!(uaddr & queue_dma_alignment(q)) &&
6728cb0e JA	58	!(len & queue_dma_alignment(q)))
86db1e29 JA	59	bio = bio_map_user(q, NULL, uaddr, len, reading);
	60	else
	61	bio = bio_copy_user(q, uaddr, len, reading);
	62
	63	if (IS_ERR(bio))
	64	return PTR_ERR(bio);
	65
	66	orig_bio = bio;
	67	blk_queue_bounce(q, &bio);
	68
	69	/*
	70	* We link the bounce buffer in and could have to traverse it
	71	* later so we have to get a ref to prevent it from being freed
	72	*/
	73	bio_get(bio);
	74
	75	ret = blk_rq_append_bio(q, rq, bio);
	76	if (!ret)
	77	return bio->bi_size;
	78
	79	/* if it was boucned we must call the end io function */
	80	bio_endio(bio, 0);
	81	__blk_rq_unmap_user(orig_bio);
	82	bio_put(bio);
	83	return ret;
	84	}
	85
	86	/**
	87	* blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
	88	* @q: request queue where request should be inserted
	89	* @rq: request structure to fill
	90	* @ubuf: the user buffer
	91	* @len: length of user data
	92	*
	93	* Description:
	94	* Data will be mapped directly for zero copy io, if possible. Otherwise
	95	* a kernel bounce buffer is used.
	96	*
	97	* A matching blk_rq_unmap_user() must be issued at the end of io, while
	98	* still in process context.
	99	*
	100	* Note: The mapped bio may need to be bounced through blk_queue_bounce()
	101	* before being submitted to the device, as pages mapped may be out of
	102	* reach. It's the callers responsibility to make sure this happens. The
	103	* original bio must be passed back in to blk_rq_unmap_user() for proper
	104	* unmapping.
	105	*/
	106	int blk_rq_map_user(struct request_queue q, struct request rq,
	107	void __user *ubuf, unsigned long len)
	108	{
	109	unsigned long bytes_read = 0;
	110	struct bio *bio = NULL;
	111	int ret;
	112
	113	if (len > (q->max_hw_sectors << 9))
	114	return -EINVAL;
	115	if (!len \|\| !ubuf)
	116	return -EINVAL;
	117
	118	while (bytes_read != len) {
	119	unsigned long map_len, end, start;
	120
	121	map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
	122	end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
123	>> PAGE_SHIFT;
124	start = (unsigned long)ubuf >> PAGE_SHIFT;
125
126	/*
127	* A bad offset could cause us to require BIO_MAX_PAGES + 1
128	* pages. If this happens we just lower the requested
129	* mapping len by a page so that we can fit
130	*/
131	if (end - start > BIO_MAX_PAGES)
132	map_len -= PAGE_SIZE;
133
134	ret = __blk_rq_map_user(q, rq, ubuf, map_len);
135	if (ret < 0)
136	goto unmap_rq;
137	if (!bio)
138	bio = rq->bio;
139	bytes_read += ret;
140	ubuf += ret;
141	}
142
40b01b9b TH	143	/*
	144	* __blk_rq_map_user() copies the buffers if starting address
	145	* or length isn't aligned. As the copied buffer is always
	146	* page aligned, we know that there's enough room for padding.
	147	* Extend the last bio and update rq->data_len accordingly.
	148	*
	149	* On unmap, bio_uncopy_user() will use unmodified
	150	* bio_map_data pointed to by bio->bi_private.
	151	*/
	152	if (len & queue_dma_alignment(q)) {
	153	unsigned int pad_len = (queue_dma_alignment(q) & ~len) + 1;
	154	struct bio *bio = rq->biotail;
	155
	156	bio->bi_io_vec[bio->bi_vcnt - 1].bv_len += pad_len;
	157	bio->bi_size += pad_len;
6b00769f	158	rq->data_len += pad_len;
40b01b9b TH	159	}
40b01b9b TH	160
86db1e29 JA	161	rq->buffer = rq->data = NULL;
	162	return 0;
	163	unmap_rq:
	164	blk_rq_unmap_user(bio);
84e9e03c	165	rq->bio = NULL;
86db1e29 JA	166	return ret;
86db1e29 JA	167	}
86db1e29 JA	168	EXPORT_SYMBOL(blk_rq_map_user);
	169
	170	/**
	171	* blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage
	172	* @q: request queue where request should be inserted
	173	* @rq: request to map data to
	174	* @iov: pointer to the iovec
	175	* @iov_count: number of elements in the iovec
	176	* @len: I/O byte count
	177	*
	178	* Description:
	179	* Data will be mapped directly for zero copy io, if possible. Otherwise
	180	* a kernel bounce buffer is used.
	181	*
	182	* A matching blk_rq_unmap_user() must be issued at the end of io, while
	183	* still in process context.
	184	*
	185	* Note: The mapped bio may need to be bounced through blk_queue_bounce()
	186	* before being submitted to the device, as pages mapped may be out of
	187	* reach. It's the callers responsibility to make sure this happens. The
	188	* original bio must be passed back in to blk_rq_unmap_user() for proper
	189	* unmapping.
	190	*/
	191	int blk_rq_map_user_iov(struct request_queue q, struct request rq,
	192	struct sg_iovec *iov, int iov_count, unsigned int len)
	193	{
	194	struct bio *bio;
	195
	196	if (!iov \|\| iov_count <= 0)
	197	return -EINVAL;
	198
	199	/* we don't allow misaligned data like bio_map_user() does. If the
	200	* user is using sg, they're expected to know the alignment constraints
	201	* and respect them accordingly */
6728cb0e JA	202	bio = bio_map_user_iov(q, NULL, iov, iov_count,
6728cb0e JA	203	rq_data_dir(rq) == READ);
86db1e29 JA	204	if (IS_ERR(bio))
	205	return PTR_ERR(bio);
	206
	207	if (bio->bi_size != len) {
	208	bio_endio(bio, 0);
	209	bio_unmap_user(bio);
	210	return -EINVAL;
	211	}
	212
	213	bio_get(bio);
	214	blk_rq_bio_prep(q, rq, bio);
	215	rq->buffer = rq->data = NULL;
	216	return 0;
	217	}
86db1e29 JA	218	EXPORT_SYMBOL(blk_rq_map_user_iov);
	219
	220	/**
	221	* blk_rq_unmap_user - unmap a request with user data
	222	* @bio: start of bio list
	223	*
	224	* Description:
	225	* Unmap a rq previously mapped by blk_rq_map_user(). The caller must
	226	* supply the original rq->bio from the blk_rq_map_user() return, since
	227	* the io completion may have changed rq->bio.
	228	*/
	229	int blk_rq_unmap_user(struct bio *bio)
	230	{
	231	struct bio *mapped_bio;
	232	int ret = 0, ret2;
	233
	234	while (bio) {
	235	mapped_bio = bio;
	236	if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
	237	mapped_bio = bio->bi_private;
	238
	239	ret2 = __blk_rq_unmap_user(mapped_bio);
	240	if (ret2 && !ret)
	241	ret = ret2;
	242
	243	mapped_bio = bio;
	244	bio = bio->bi_next;
	245	bio_put(mapped_bio);
	246	}
	247
	248	return ret;
	249	}
86db1e29 JA	250	EXPORT_SYMBOL(blk_rq_unmap_user);
	251
	252	/**
	253	* blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage
	254	* @q: request queue where request should be inserted
	255	* @rq: request to fill
	256	* @kbuf: the kernel buffer
	257	* @len: length of user data
	258	* @gfp_mask: memory allocation flags
	259	*/
	260	int blk_rq_map_kern(struct request_queue q, struct request rq, void *kbuf,
	261	unsigned int len, gfp_t gfp_mask)
	262	{
	263	struct bio *bio;
	264
	265	if (len > (q->max_hw_sectors << 9))
	266	return -EINVAL;
	267	if (!len \|\| !kbuf)
	268	return -EINVAL;
	269
	270	bio = bio_map_kern(q, kbuf, len, gfp_mask);
	271	if (IS_ERR(bio))
	272	return PTR_ERR(bio);
	273
	274	if (rq_data_dir(rq) == WRITE)
	275	bio->bi_rw \|= (1 << BIO_RW);
	276
	277	blk_rq_bio_prep(q, rq, bio);
	278	blk_queue_bounce(q, &rq->bio);
	279	rq->buffer = rq->data = NULL;
	280	return 0;
	281	}
86db1e29	282	EXPORT_SYMBOL(blk_rq_map_kern);