[linux-2.6-block.git] / drivers / dma / iovlock.c

/*
 * Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
 * Portions based on net/core/datagram.c and copyrighted by their authors.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * The full GNU General Public License is included in this distribution in the
 * file called COPYING.
 */

/*
 * This code allows the net stack to make use of a DMA engine for
 * skb to iovec copies.
 */

#include <linux/dmaengine.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <net/tcp.h> /* for memcpy_toiovec */
#include <asm/io.h>
#include <asm/uaccess.h>

static int num_pages_spanned(struct iovec *iov)
{
	return
	((PAGE_ALIGN((unsigned long)iov->iov_base + iov->iov_len) -
	((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT);
}

/*
 * Pin down all the iovec pages needed for len bytes.
 * Return a struct dma_pinned_list to keep track of pages pinned down.
 *
 * We are allocating a single chunk of memory, and then carving it up into
 * 3 sections, the latter 2 whose size depends on the number of iovecs and the
 * total number of pages, respectively.
 */
struct dma_pinned_list *dma_pin_iovec_pages(struct iovec *iov, size_t len)
{
	struct dma_pinned_list *local_list;
	struct page **pages;
	int i;
	int ret;
	int nr_iovecs = 0;
	int iovec_len_used = 0;
	int iovec_pages_used = 0;

	/* don't pin down non-user-based iovecs */
	if (segment_eq(get_fs(), KERNEL_DS))
		return NULL;

	/* determine how many iovecs/pages there are, up front */
	do {
		iovec_len_used += iov[nr_iovecs].iov_len;
		iovec_pages_used += num_pages_spanned(&iov[nr_iovecs]);
		nr_iovecs++;
	} while (iovec_len_used < len);

	/* single kmalloc for pinned list, page_list[], and the page arrays */
	local_list = kmalloc(sizeof(*local_list)
		+ (nr_iovecs * sizeof (struct dma_page_list))
		+ (iovec_pages_used * sizeof (struct page*)), GFP_KERNEL);
	if (!local_list)
		goto out;

	/* list of pages starts right after the page list array */
	pages = (struct page **) &local_list->page_list[nr_iovecs];

	local_list->nr_iovecs = 0;

	for (i = 0; i < nr_iovecs; i++) {
		struct dma_page_list *page_list = &local_list->page_list[i];

		len -= iov[i].iov_len;

		if (!access_ok(VERIFY_WRITE, iov[i].iov_base, iov[i].iov_len))
			goto unpin;

		page_list->nr_pages = num_pages_spanned(&iov[i]);
		page_list->base_address = iov[i].iov_base;

		page_list->pages = pages;
		pages += page_list->nr_pages;

		/* pin pages down */
		down_read(&current->mm->mmap_sem);
		ret = get_user_pages(
			current,
			current->mm,
			(unsigned long) iov[i].iov_base,
			page_list->nr_pages,
			1,	/* write */
			0,	/* force */
			page_list->pages,
			NULL);
		up_read(&current->mm->mmap_sem);

		if (ret != page_list->nr_pages)
			goto unpin;

		local_list->nr_iovecs = i + 1;
	}

	return local_list;

unpin:
	dma_unpin_iovec_pages(local_list);
out:
	return NULL;
}

void dma_unpin_iovec_pages(struct dma_pinned_list *pinned_list)
{
	int i, j;

	if (!pinned_list)
		return;

	for (i = 0; i < pinned_list->nr_iovecs; i++) {
		struct dma_page_list *page_list = &pinned_list->page_list[i];
		for (j = 0; j < page_list->nr_pages; j++) {
			set_page_dirty_lock(page_list->pages[j]);
			page_cache_release(page_list->pages[j]);
		}
	}

	kfree(pinned_list);
}


/*
 * We have already pinned down the pages we will be using in the iovecs.
 * Each entry in iov array has corresponding entry in pinned_list->page_list.
 * Using array indexing to keep iov[] and page_list[] in sync.
 * Initial elements in iov array's iov->iov_len will be 0 if already copied into
 *   by another call.
 * iov array length remaining guaranteed to be bigger than len.
 */
dma_cookie_t dma_memcpy_to_iovec(struct dma_chan *chan, struct iovec *iov,
	struct dma_pinned_list *pinned_list, unsigned char *kdata, size_t len)
{
	int iov_byte_offset;
	int copy;
	dma_cookie_t dma_cookie = 0;
	int iovec_idx;
	int page_idx;

	if (!chan)
		return memcpy_toiovec(iov, kdata, len);

	iovec_idx = 0;
	while (iovec_idx < pinned_list->nr_iovecs) {
		struct dma_page_list *page_list;

		/* skip already used-up iovecs */
		while (!iov[iovec_idx].iov_len)
			iovec_idx++;

		page_list = &pinned_list->page_list[iovec_idx];

		iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK);
		page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK)
			 - ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT;

		/* break up copies to not cross page boundary */
		while (iov[iovec_idx].iov_len) {
			copy = min_t(int, PAGE_SIZE - iov_byte_offset, len);
			copy = min_t(int, copy, iov[iovec_idx].iov_len);

			dma_cookie = dma_async_memcpy_buf_to_pg(chan,
					page_list->pages[page_idx],
					iov_byte_offset,
					kdata,
					copy);
			/* poll for a descriptor slot */
			if (unlikely(dma_cookie < 0)) {
				dma_async_issue_pending(chan);
				continue;
			}

			len -= copy;
			iov[iovec_idx].iov_len -= copy;
			iov[iovec_idx].iov_base += copy;

			if (!len)
				return dma_cookie;

			kdata += copy;
			iov_byte_offset = 0;
			page_idx++;
		}
		iovec_idx++;
	}

	/* really bad if we ever run out of iovecs */
	BUG();
	return -EFAULT;
}

dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan *chan, struct iovec *iov,
	struct dma_pinned_list *pinned_list, struct page *page,
	unsigned int offset, size_t len)
{
	int iov_byte_offset;
	int copy;
	dma_cookie_t dma_cookie = 0;
	int iovec_idx;
	int page_idx;
	int err;

	/* this needs as-yet-unimplemented buf-to-buff, so punt. */
	/* TODO: use dma for this */
	if (!chan || !pinned_list) {
		u8 *vaddr = kmap(page);
		err = memcpy_toiovec(iov, vaddr + offset, len);
		kunmap(page);
		return err;
	}

	iovec_idx = 0;
	while (iovec_idx < pinned_list->nr_iovecs) {
		struct dma_page_list *page_list;

		/* skip already used-up iovecs */
		while (!iov[iovec_idx].iov_len)
			iovec_idx++;

		page_list = &pinned_list->page_list[iovec_idx];

		iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK);
		page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK)
			 - ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT;

		/* break up copies to not cross page boundary */
		while (iov[iovec_idx].iov_len) {
			copy = min_t(int, PAGE_SIZE - iov_byte_offset, len);
			copy = min_t(int, copy, iov[iovec_idx].iov_len);

			dma_cookie = dma_async_memcpy_pg_to_pg(chan,
					page_list->pages[page_idx],
					iov_byte_offset,
					page,
					offset,
					copy);
			/* poll for a descriptor slot */
			if (unlikely(dma_cookie < 0)) {
				dma_async_issue_pending(chan);
				continue;
			}

			len -= copy;
			iov[iovec_idx].iov_len -= copy;
			iov[iovec_idx].iov_base += copy;

			if (!len)
				return dma_cookie;

			offset += copy;
			iov_byte_offset = 0;
			page_idx++;
		}
		iovec_idx++;
	}

	/* really bad if we ever run out of iovecs */
	BUG();
	return -EFAULT;
}
Commit	Line	Data
de5506e1 CL	1	/*
	2	* Copyright(c) 2004 - 2006 Intel Corporation. All rights reserved.
	3	* Portions based on net/core/datagram.c and copyrighted by their authors.
	4	*
	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms of the GNU General Public License as published by the Free
	7	* Software Foundation; either version 2 of the License, or (at your option)
	8	* any later version.
	9	*
	10	* This program is distributed in the hope that it will be useful, but WITHOUT
	11	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	12	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	13	* more details.
	14	*
	15	* You should have received a copy of the GNU General Public License along with
	16	* this program; if not, write to the Free Software Foundation, Inc., 59
	17	* Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	18	*
	19	* The full GNU General Public License is included in this distribution in the
	20	* file called COPYING.
	21	*/
	22
	23	/*
	24	* This code allows the net stack to make use of a DMA engine for
	25	* skb to iovec copies.
	26	*/
	27
	28	#include <linux/dmaengine.h>
	29	#include <linux/pagemap.h>
5a0e3ad6	30	#include <linux/slab.h>
de5506e1 CL	31	#include <net/tcp.h> /* for memcpy_toiovec */
	32	#include <asm/io.h>
	33	#include <asm/uaccess.h>
	34
56e0873b	35	static int num_pages_spanned(struct iovec *iov)
de5506e1 CL	36	{
	37	return
	38	((PAGE_ALIGN((unsigned long)iov->iov_base + iov->iov_len) -
	39	((unsigned long)iov->iov_base & PAGE_MASK)) >> PAGE_SHIFT);
	40	}
	41
	42	/*
	43	* Pin down all the iovec pages needed for len bytes.
	44	* Return a struct dma_pinned_list to keep track of pages pinned down.
	45	*
	46	* We are allocating a single chunk of memory, and then carving it up into
	47	* 3 sections, the latter 2 whose size depends on the number of iovecs and the
	48	* total number of pages, respectively.
	49	*/
	50	struct dma_pinned_list dma_pin_iovec_pages(struct iovec iov, size_t len)
	51	{
	52	struct dma_pinned_list *local_list;
	53	struct page **pages;
	54	int i;
	55	int ret;
	56	int nr_iovecs = 0;
	57	int iovec_len_used = 0;
	58	int iovec_pages_used = 0;
de5506e1 CL	59
	60	/* don't pin down non-user-based iovecs */
	61	if (segment_eq(get_fs(), KERNEL_DS))
	62	return NULL;
	63
	64	/* determine how many iovecs/pages there are, up front */
	65	do {
	66	iovec_len_used += iov[nr_iovecs].iov_len;
	67	iovec_pages_used += num_pages_spanned(&iov[nr_iovecs]);
	68	nr_iovecs++;
	69	} while (iovec_len_used < len);
	70
	71	/* single kmalloc for pinned list, page_list[], and the page arrays */
	72	local_list = kmalloc(sizeof(*local_list)
	73	+ (nr_iovecs * sizeof (struct dma_page_list))
	74	+ (iovec_pages_used * sizeof (struct page*)), GFP_KERNEL);
c2c0b4c5	75	if (!local_list)
de5506e1	76	goto out;
de5506e1 CL	77
	78	/* list of pages starts right after the page list array */
	79	pages = (struct page **) &local_list->page_list[nr_iovecs];
	80
c2c0b4c5 MS	81	local_list->nr_iovecs = 0;
c2c0b4c5 MS	82
de5506e1 CL	83	for (i = 0; i < nr_iovecs; i++) {
	84	struct dma_page_list *page_list = &local_list->page_list[i];
	85
	86	len -= iov[i].iov_len;
	87
c2c0b4c5	88	if (!access_ok(VERIFY_WRITE, iov[i].iov_base, iov[i].iov_len))
de5506e1	89	goto unpin;
de5506e1 CL	90
	91	page_list->nr_pages = num_pages_spanned(&iov[i]);
	92	page_list->base_address = iov[i].iov_base;
	93
	94	page_list->pages = pages;
	95	pages += page_list->nr_pages;
	96
	97	/* pin pages down */
	98	down_read(&current->mm->mmap_sem);
	99	ret = get_user_pages(
	100	current,
	101	current->mm,
	102	(unsigned long) iov[i].iov_base,
	103	page_list->nr_pages,
	104	1, /* write */
	105	0, /* force */
	106	page_list->pages,
	107	NULL);
	108	up_read(&current->mm->mmap_sem);
	109
c2c0b4c5	110	if (ret != page_list->nr_pages)
de5506e1	111	goto unpin;
de5506e1 CL	112
	113	local_list->nr_iovecs = i + 1;
	114	}
	115
	116	return local_list;
	117
	118	unpin:
	119	dma_unpin_iovec_pages(local_list);
	120	out:
c2c0b4c5	121	return NULL;
de5506e1 CL	122	}
	123
	124	void dma_unpin_iovec_pages(struct dma_pinned_list *pinned_list)
	125	{
	126	int i, j;
	127
	128	if (!pinned_list)
	129	return;
	130
	131	for (i = 0; i < pinned_list->nr_iovecs; i++) {
	132	struct dma_page_list *page_list = &pinned_list->page_list[i];
	133	for (j = 0; j < page_list->nr_pages; j++) {
	134	set_page_dirty_lock(page_list->pages[j]);
	135	page_cache_release(page_list->pages[j]);
	136	}
	137	}
	138
	139	kfree(pinned_list);
	140	}
	141
de5506e1 CL	142
	143	/*
	144	* We have already pinned down the pages we will be using in the iovecs.
	145	* Each entry in iov array has corresponding entry in pinned_list->page_list.
	146	* Using array indexing to keep iov[] and page_list[] in sync.
	147	* Initial elements in iov array's iov->iov_len will be 0 if already copied into
	148	* by another call.
	149	* iov array length remaining guaranteed to be bigger than len.
	150	*/
	151	dma_cookie_t dma_memcpy_to_iovec(struct dma_chan chan, struct iovec iov,
	152	struct dma_pinned_list pinned_list, unsigned char kdata, size_t len)
	153	{
	154	int iov_byte_offset;
	155	int copy;
	156	dma_cookie_t dma_cookie = 0;
	157	int iovec_idx;
	158	int page_idx;
	159
	160	if (!chan)
	161	return memcpy_toiovec(iov, kdata, len);
	162
de5506e1 CL	163	iovec_idx = 0;
	164	while (iovec_idx < pinned_list->nr_iovecs) {
	165	struct dma_page_list *page_list;
	166
	167	/* skip already used-up iovecs */
	168	while (!iov[iovec_idx].iov_len)
	169	iovec_idx++;
	170
	171	page_list = &pinned_list->page_list[iovec_idx];
	172
	173	iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK);
	174	page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK)
	175	- ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT;
	176
	177	/* break up copies to not cross page boundary */
	178	while (iov[iovec_idx].iov_len) {
	179	copy = min_t(int, PAGE_SIZE - iov_byte_offset, len);
	180	copy = min_t(int, copy, iov[iovec_idx].iov_len);
	181
	182	dma_cookie = dma_async_memcpy_buf_to_pg(chan,
	183	page_list->pages[page_idx],
	184	iov_byte_offset,
	185	kdata,
	186	copy);
4b652f0d DW	187	/* poll for a descriptor slot */
	188	if (unlikely(dma_cookie < 0)) {
	189	dma_async_issue_pending(chan);
	190	continue;
	191	}
de5506e1 CL	192
	193	len -= copy;
	194	iov[iovec_idx].iov_len -= copy;
	195	iov[iovec_idx].iov_base += copy;
	196
	197	if (!len)
	198	return dma_cookie;
	199
	200	kdata += copy;
	201	iov_byte_offset = 0;
	202	page_idx++;
	203	}
	204	iovec_idx++;
	205	}
	206
	207	/* really bad if we ever run out of iovecs */
	208	BUG();
	209	return -EFAULT;
	210	}
	211
	212	dma_cookie_t dma_memcpy_pg_to_iovec(struct dma_chan chan, struct iovec iov,
	213	struct dma_pinned_list pinned_list, struct page page,
	214	unsigned int offset, size_t len)
	215	{
	216	int iov_byte_offset;
	217	int copy;
	218	dma_cookie_t dma_cookie = 0;
	219	int iovec_idx;
	220	int page_idx;
	221	int err;
	222
	223	/* this needs as-yet-unimplemented buf-to-buff, so punt. */
	224	/* TODO: use dma for this */
	225	if (!chan \|\| !pinned_list) {
	226	u8 *vaddr = kmap(page);
	227	err = memcpy_toiovec(iov, vaddr + offset, len);
	228	kunmap(page);
	229	return err;
	230	}
	231
	232	iovec_idx = 0;
	233	while (iovec_idx < pinned_list->nr_iovecs) {
	234	struct dma_page_list *page_list;
	235
	236	/* skip already used-up iovecs */
	237	while (!iov[iovec_idx].iov_len)
	238	iovec_idx++;
	239
	240	page_list = &pinned_list->page_list[iovec_idx];
	241
	242	iov_byte_offset = ((unsigned long)iov[iovec_idx].iov_base & ~PAGE_MASK);
	243	page_idx = (((unsigned long)iov[iovec_idx].iov_base & PAGE_MASK)
	244	- ((unsigned long)page_list->base_address & PAGE_MASK)) >> PAGE_SHIFT;
	245
	246	/* break up copies to not cross page boundary */
	247	while (iov[iovec_idx].iov_len) {
	248	copy = min_t(int, PAGE_SIZE - iov_byte_offset, len);
	249	copy = min_t(int, copy, iov[iovec_idx].iov_len);
	250
	251	dma_cookie = dma_async_memcpy_pg_to_pg(chan,
	252	page_list->pages[page_idx],
	253	iov_byte_offset,
	254	page,
	255	offset,
256	copy);
4b652f0d DW	257	/* poll for a descriptor slot */
	258	if (unlikely(dma_cookie < 0)) {
	259	dma_async_issue_pending(chan);
	260	continue;
	261	}
de5506e1 CL	262
	263	len -= copy;
	264	iov[iovec_idx].iov_len -= copy;
	265	iov[iovec_idx].iov_base += copy;
	266
	267	if (!len)
	268	return dma_cookie;
	269
	270	offset += copy;
	271	iov_byte_offset = 0;
	272	page_idx++;
	273	}
	274	iovec_idx++;
	275	}
	276
	277	/* really bad if we ever run out of iovecs */
	278	BUG();
	279	return -EFAULT;
	280	}