[linux.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;
}
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;
	unsigned int alignment;
	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;
	alignment = queue_dma_alignment(q) | q->dma_pad_mask;
	if (!(uaddr & alignment) && !(len & alignment))
		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;
	}

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

	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;
	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 (unaligned || (q->dma_pad_mask & len))
		bio = bio_copy_user_iov(q, iov, iov_count, read);
	else
		bio = bio_map_user_iov(q, NULL, iov, iov_count, read);

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

	if (bio->bi_size != len) {
		bio_endio(bio, 0);
		bio_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 = rq->data = NULL;
	return 0;
}

/**
 * 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
 *
 * Description:
 *    Data will be mapped directly if possible. Otherwise a bounce
 *    buffer is used.
 */
int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
		    unsigned int len, gfp_t gfp_mask)
{
	unsigned long kaddr;
	unsigned int alignment;
	int reading = rq_data_dir(rq) == READ;
	int do_copy = 0;
	struct bio *bio;
	unsigned long stack_mask = ~(THREAD_SIZE - 1);

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

	kaddr = (unsigned long)kbuf;
	alignment = queue_dma_alignment(q) | q->dma_pad_mask;
	do_copy = ((kaddr & alignment) || (len & alignment));

	if (!((kaddr & stack_mask) ^
	      ((unsigned long)current->stack & stack_mask)))
		do_copy = 1;

	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 |= (1 << BIO_RW);

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

	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>
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
	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;
e3790c7d	47	unsigned int alignment;
86db1e29 JA	48	struct bio bio, orig_bio;
	49	int reading, ret;
	50
	51	reading = rq_data_dir(rq) == READ;
	52
	53	/*
	54	* if alignment requirement is satisfied, map in user pages for
	55	* direct dma. else, set up kernel bounce buffers
	56	*/
	57	uaddr = (unsigned long) ubuf;
e3790c7d TH	58	alignment = queue_dma_alignment(q) \| q->dma_pad_mask;
e3790c7d TH	59	if (!(uaddr & alignment) && !(len & alignment))
86db1e29 JA	60	bio = bio_map_user(q, NULL, uaddr, len, reading);
	61	else
	62	bio = bio_copy_user(q, uaddr, len, reading);
	63
	64	if (IS_ERR(bio))
	65	return PTR_ERR(bio);
	66
	67	orig_bio = bio;
	68	blk_queue_bounce(q, &bio);
	69
	70	/*
	71	* We link the bounce buffer in and could have to traverse it
	72	* later so we have to get a ref to prevent it from being freed
	73	*/
	74	bio_get(bio);
	75
	76	ret = blk_rq_append_bio(q, rq, bio);
	77	if (!ret)
	78	return bio->bi_size;
	79
	80	/* if it was boucned we must call the end io function */
	81	bio_endio(bio, 0);
	82	__blk_rq_unmap_user(orig_bio);
	83	bio_put(bio);
	84	return ret;
	85	}
	86
	87	/**
	88	* blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
	89	* @q: request queue where request should be inserted
	90	* @rq: request structure to fill
	91	* @ubuf: the user buffer
	92	* @len: length of user data
	93	*
	94	* Description:
	95	* Data will be mapped directly for zero copy io, if possible. Otherwise
	96	* a kernel bounce buffer is used.
	97	*
	98	* A matching blk_rq_unmap_user() must be issued at the end of io, while
	99	* still in process context.
	100	*
	101	* Note: The mapped bio may need to be bounced through blk_queue_bounce()
	102	* before being submitted to the device, as pages mapped may be out of
	103	* reach. It's the callers responsibility to make sure this happens. The
	104	* original bio must be passed back in to blk_rq_unmap_user() for proper
	105	* unmapping.
	106	*/
	107	int blk_rq_map_user(struct request_queue q, struct request rq,
	108	void __user *ubuf, unsigned long len)
	109	{
	110	unsigned long bytes_read = 0;
	111	struct bio *bio = NULL;
	112	int ret;
	113
	114	if (len > (q->max_hw_sectors << 9))
	115	return -EINVAL;
	116	if (!len \|\| !ubuf)
	117	return -EINVAL;
	118
	119	while (bytes_read != len) {
	120	unsigned long map_len, end, start;
	121
	122	map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
	123	end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
124	>> PAGE_SHIFT;
125	start = (unsigned long)ubuf >> PAGE_SHIFT;
126
127	/*
128	* A bad offset could cause us to require BIO_MAX_PAGES + 1
129	* pages. If this happens we just lower the requested
130	* mapping len by a page so that we can fit
131	*/
132	if (end - start > BIO_MAX_PAGES)
133	map_len -= PAGE_SIZE;
134
135	ret = __blk_rq_map_user(q, rq, ubuf, map_len);
136	if (ret < 0)
137	goto unmap_rq;
138	if (!bio)
139	bio = rq->bio;
140	bytes_read += ret;
141	ubuf += ret;
142	}
143
f18573ab FT	144	if (!bio_flagged(bio, BIO_USER_MAPPED))
f18573ab FT	145	rq->cmd_flags \|= REQ_COPY_USER;
40b01b9b	146
86db1e29 JA	147	rq->buffer = rq->data = NULL;
	148	return 0;
	149	unmap_rq:
	150	blk_rq_unmap_user(bio);
84e9e03c	151	rq->bio = NULL;
86db1e29 JA	152	return ret;
86db1e29 JA	153	}
86db1e29 JA	154	EXPORT_SYMBOL(blk_rq_map_user);
	155
	156	/**
	157	* blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage
	158	* @q: request queue where request should be inserted
	159	* @rq: request to map data to
	160	* @iov: pointer to the iovec
	161	* @iov_count: number of elements in the iovec
	162	* @len: I/O byte count
	163	*
	164	* Description:
	165	* Data will be mapped directly for zero copy io, if possible. Otherwise
	166	* a kernel bounce buffer is used.
	167	*
	168	* A matching blk_rq_unmap_user() must be issued at the end of io, while
	169	* still in process context.
	170	*
	171	* Note: The mapped bio may need to be bounced through blk_queue_bounce()
	172	* before being submitted to the device, as pages mapped may be out of
	173	* reach. It's the callers responsibility to make sure this happens. The
	174	* original bio must be passed back in to blk_rq_unmap_user() for proper
	175	* unmapping.
	176	*/
	177	int blk_rq_map_user_iov(struct request_queue q, struct request rq,
	178	struct sg_iovec *iov, int iov_count, unsigned int len)
	179	{
	180	struct bio *bio;
afdc1a78 FT	181	int i, read = rq_data_dir(rq) == READ;
afdc1a78 FT	182	int unaligned = 0;
86db1e29 JA	183
	184	if (!iov \|\| iov_count <= 0)
	185	return -EINVAL;
	186
afdc1a78 FT	187	for (i = 0; i < iov_count; i++) {
	188	unsigned long uaddr = (unsigned long)iov[i].iov_base;
	189
	190	if (uaddr & queue_dma_alignment(q)) {
	191	unaligned = 1;
	192	break;
	193	}
	194	}
	195
	196	if (unaligned \|\| (q->dma_pad_mask & len))
	197	bio = bio_copy_user_iov(q, iov, iov_count, read);
	198	else
	199	bio = bio_map_user_iov(q, NULL, iov, iov_count, read);
	200
86db1e29 JA	201	if (IS_ERR(bio))
	202	return PTR_ERR(bio);
	203
	204	if (bio->bi_size != len) {
	205	bio_endio(bio, 0);
	206	bio_unmap_user(bio);
	207	return -EINVAL;
	208	}
	209
f18573ab FT	210	if (!bio_flagged(bio, BIO_USER_MAPPED))
	211	rq->cmd_flags \|= REQ_COPY_USER;
	212
07359fc6	213	blk_queue_bounce(q, &bio);
86db1e29 JA	214	bio_get(bio);
	215	blk_rq_bio_prep(q, rq, bio);
	216	rq->buffer = rq->data = NULL;
	217	return 0;
	218	}
86db1e29 JA	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
68154e90 FT	259	*
	260	* Description:
	261	* Data will be mapped directly if possible. Otherwise a bounce
	262	* buffer is used.
86db1e29 JA	263	*/
	264	int blk_rq_map_kern(struct request_queue q, struct request rq, void *kbuf,
	265	unsigned int len, gfp_t gfp_mask)
	266	{
68154e90 FT	267	unsigned long kaddr;
	268	unsigned int alignment;
	269	int reading = rq_data_dir(rq) == READ;
	270	int do_copy = 0;
86db1e29	271	struct bio *bio;
30c00eda	272	unsigned long stack_mask = ~(THREAD_SIZE - 1);
86db1e29 JA	273
	274	if (len > (q->max_hw_sectors << 9))
	275	return -EINVAL;
	276	if (!len \|\| !kbuf)
	277	return -EINVAL;
	278
68154e90 FT	279	kaddr = (unsigned long)kbuf;
	280	alignment = queue_dma_alignment(q) \| q->dma_pad_mask;
	281	do_copy = ((kaddr & alignment) \|\| (len & alignment));
	282
30c00eda FT	283	if (!((kaddr & stack_mask) ^
	284	((unsigned long)current->stack & stack_mask)))
	285	do_copy = 1;
	286
68154e90 FT	287	if (do_copy)
	288	bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
	289	else
	290	bio = bio_map_kern(q, kbuf, len, gfp_mask);
	291
86db1e29 JA	292	if (IS_ERR(bio))
	293	return PTR_ERR(bio);
	294
	295	if (rq_data_dir(rq) == WRITE)
	296	bio->bi_rw \|= (1 << BIO_RW);
	297
68154e90 FT	298	if (do_copy)
	299	rq->cmd_flags \|= REQ_COPY_USER;
	300
86db1e29 JA	301	blk_rq_bio_prep(q, rq, bio);
	302	blk_queue_bounce(q, &rq->bio);
	303	rq->buffer = rq->data = NULL;
	304	return 0;
	305	}
86db1e29	306	EXPORT_SYMBOL(blk_rq_map_kern);