[mirror_ubuntu-eoan-kernel.git] / block / bounce.c

// SPDX-License-Identifier: GPL-2.0
/* bounce buffer handling for block devices
 *
 * - Split from highmem.c
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/mm.h>
#include <linux/export.h>
#include <linux/swap.h>
#include <linux/gfp.h>
#include <linux/bio.h>
#include <linux/pagemap.h>
#include <linux/mempool.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/init.h>
#include <linux/hash.h>
#include <linux/highmem.h>
#include <linux/bootmem.h>
#include <linux/printk.h>
#include <asm/tlbflush.h>

#include <trace/events/block.h>
#include "blk.h"

#define POOL_SIZE	64
#define ISA_POOL_SIZE	16

static struct bio_set bounce_bio_set, bounce_bio_split;
static mempool_t page_pool, isa_page_pool;

#if defined(CONFIG_HIGHMEM)
static __init int init_emergency_pool(void)
{
	int ret;
#if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG)
	if (max_pfn <= max_low_pfn)
		return 0;
#endif

	ret = mempool_init_page_pool(&page_pool, POOL_SIZE, 0);
	BUG_ON(ret);
	pr_info("pool size: %d pages\n", POOL_SIZE);

	ret = bioset_init(&bounce_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
	BUG_ON(ret);
	if (bioset_integrity_create(&bounce_bio_set, BIO_POOL_SIZE))
		BUG_ON(1);

	ret = bioset_init(&bounce_bio_split, BIO_POOL_SIZE, 0, 0);
	BUG_ON(ret);

	return 0;
}

__initcall(init_emergency_pool);
#endif

#ifdef CONFIG_HIGHMEM
/*
 * highmem version, map in to vec
 */
static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
{
	unsigned char *vto;

	vto = kmap_atomic(to->bv_page);
	memcpy(vto + to->bv_offset, vfrom, to->bv_len);
	kunmap_atomic(vto);
}

#else /* CONFIG_HIGHMEM */

#define bounce_copy_vec(to, vfrom)	\
	memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)

#endif /* CONFIG_HIGHMEM */

/*
 * allocate pages in the DMA region for the ISA pool
 */
static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data)
{
	return mempool_alloc_pages(gfp_mask | GFP_DMA, data);
}

/*
 * gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
 * as the max address, so check if the pool has already been created.
 */
int init_emergency_isa_pool(void)
{
	int ret;

	if (mempool_initialized(&isa_page_pool))
		return 0;

	ret = mempool_init(&isa_page_pool, ISA_POOL_SIZE, mempool_alloc_pages_isa,
			   mempool_free_pages, (void *) 0);
	BUG_ON(ret);

	pr_info("isa pool size: %d pages\n", ISA_POOL_SIZE);
	return 0;
}

/*
 * Simple bounce buffer support for highmem pages. Depending on the
 * queue gfp mask set, *to may or may not be a highmem page. kmap it
 * always, it will do the Right Thing
 */
static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
{
	unsigned char *vfrom;
	struct bio_vec tovec, fromvec;
	struct bvec_iter iter;
	/*
	 * The bio of @from is created by bounce, so we can iterate
	 * its bvec from start to end, but the @from->bi_iter can't be
	 * trusted because it might be changed by splitting.
	 */
	struct bvec_iter from_iter = BVEC_ITER_ALL_INIT;

	bio_for_each_segment(tovec, to, iter) {
		fromvec = bio_iter_iovec(from, from_iter);
		if (tovec.bv_page != fromvec.bv_page) {
			/*
			 * fromvec->bv_offset and fromvec->bv_len might have
			 * been modified by the block layer, so use the original
			 * copy, bounce_copy_vec already uses tovec->bv_len
			 */
			vfrom = page_address(fromvec.bv_page) +
				tovec.bv_offset;

			bounce_copy_vec(&tovec, vfrom);
			flush_dcache_page(tovec.bv_page);
		}
		bio_advance_iter(from, &from_iter, tovec.bv_len);
	}
}

static void bounce_end_io(struct bio *bio, mempool_t *pool)
{
	struct bio *bio_orig = bio->bi_private;
	struct bio_vec *bvec, orig_vec;
	int i;
	struct bvec_iter orig_iter = bio_orig->bi_iter;

	/*
	 * free up bounce indirect pages used
	 */
	bio_for_each_segment_all(bvec, bio, i) {
		orig_vec = bio_iter_iovec(bio_orig, orig_iter);
		if (bvec->bv_page != orig_vec.bv_page) {
			dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
			mempool_free(bvec->bv_page, pool);
		}
		bio_advance_iter(bio_orig, &orig_iter, orig_vec.bv_len);
	}

	bio_orig->bi_status = bio->bi_status;
	bio_endio(bio_orig);
	bio_put(bio);
}

static void bounce_end_io_write(struct bio *bio)
{
	bounce_end_io(bio, &page_pool);
}

static void bounce_end_io_write_isa(struct bio *bio)
{

	bounce_end_io(bio, &isa_page_pool);
}

static void __bounce_end_io_read(struct bio *bio, mempool_t *pool)
{
	struct bio *bio_orig = bio->bi_private;

	if (!bio->bi_status)
		copy_to_high_bio_irq(bio_orig, bio);

	bounce_end_io(bio, pool);
}

static void bounce_end_io_read(struct bio *bio)
{
	__bounce_end_io_read(bio, &page_pool);
}

static void bounce_end_io_read_isa(struct bio *bio)
{
	__bounce_end_io_read(bio, &isa_page_pool);
}

static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask,
		struct bio_set *bs)
{
	struct bvec_iter iter;
	struct bio_vec bv;
	struct bio *bio;

	/*
	 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from
	 * bio_src->bi_io_vec to bio->bi_io_vec.
	 *
	 * We can't do that anymore, because:
	 *
	 *  - The point of cloning the biovec is to produce a bio with a biovec
	 *    the caller can modify: bi_idx and bi_bvec_done should be 0.
	 *
	 *  - The original bio could've had more than BIO_MAX_PAGES biovecs; if
	 *    we tried to clone the whole thing bio_alloc_bioset() would fail.
	 *    But the clone should succeed as long as the number of biovecs we
	 *    actually need to allocate is fewer than BIO_MAX_PAGES.
	 *
	 *  - Lastly, bi_vcnt should not be looked at or relied upon by code
	 *    that does not own the bio - reason being drivers don't use it for
	 *    iterating over the biovec anymore, so expecting it to be kept up
	 *    to date (i.e. for clones that share the parent biovec) is just
	 *    asking for trouble and would force extra work on
	 *    __bio_clone_fast() anyways.
	 */

	bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs);
	if (!bio)
		return NULL;
	bio->bi_disk		= bio_src->bi_disk;
	bio->bi_opf		= bio_src->bi_opf;
	bio->bi_write_hint	= bio_src->bi_write_hint;
	bio->bi_iter.bi_sector	= bio_src->bi_iter.bi_sector;
	bio->bi_iter.bi_size	= bio_src->bi_iter.bi_size;

	switch (bio_op(bio)) {
	case REQ_OP_DISCARD:
	case REQ_OP_SECURE_ERASE:
	case REQ_OP_WRITE_ZEROES:
		break;
	case REQ_OP_WRITE_SAME:
		bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0];
		break;
	default:
		bio_for_each_segment(bv, bio_src, iter)
			bio->bi_io_vec[bio->bi_vcnt++] = bv;
		break;
	}

	if (bio_integrity(bio_src)) {
		int ret;

		ret = bio_integrity_clone(bio, bio_src, gfp_mask);
		if (ret < 0) {
			bio_put(bio);
			return NULL;
		}
	}

	bio_clone_blkcg_association(bio, bio_src);

	return bio;
}

static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
			       mempool_t *pool)
{
	struct bio *bio;
	int rw = bio_data_dir(*bio_orig);
	struct bio_vec *to, from;
	struct bvec_iter iter;
	unsigned i = 0;
	bool bounce = false;
	int sectors = 0;
	bool passthrough = bio_is_passthrough(*bio_orig);

	bio_for_each_segment(from, *bio_orig, iter) {
		if (i++ < BIO_MAX_PAGES)
			sectors += from.bv_len >> 9;
		if (page_to_pfn(from.bv_page) > q->limits.bounce_pfn)
			bounce = true;
	}
	if (!bounce)
		return;

	if (!passthrough && sectors < bio_sectors(*bio_orig)) {
		bio = bio_split(*bio_orig, sectors, GFP_NOIO, &bounce_bio_split);
		bio_chain(bio, *bio_orig);
		generic_make_request(*bio_orig);
		*bio_orig = bio;
	}
	bio = bounce_clone_bio(*bio_orig, GFP_NOIO, passthrough ? NULL :
			&bounce_bio_set);

	bio_for_each_segment_all(to, bio, i) {
		struct page *page = to->bv_page;

		if (page_to_pfn(page) <= q->limits.bounce_pfn)
			continue;

		to->bv_page = mempool_alloc(pool, q->bounce_gfp);
		inc_zone_page_state(to->bv_page, NR_BOUNCE);

		if (rw == WRITE) {
			char *vto, *vfrom;

			flush_dcache_page(page);

			vto = page_address(to->bv_page) + to->bv_offset;
			vfrom = kmap_atomic(page) + to->bv_offset;
			memcpy(vto, vfrom, to->bv_len);
			kunmap_atomic(vfrom);
		}
	}

	trace_block_bio_bounce(q, *bio_orig);

	bio->bi_flags |= (1 << BIO_BOUNCED);

	if (pool == &page_pool) {
		bio->bi_end_io = bounce_end_io_write;
		if (rw == READ)
			bio->bi_end_io = bounce_end_io_read;
	} else {
		bio->bi_end_io = bounce_end_io_write_isa;
		if (rw == READ)
			bio->bi_end_io = bounce_end_io_read_isa;
	}

	bio->bi_private = *bio_orig;
	*bio_orig = bio;
}

void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
{
	mempool_t *pool;

	/*
	 * Data-less bio, nothing to bounce
	 */
	if (!bio_has_data(*bio_orig))
		return;

	/*
	 * for non-isa bounce case, just check if the bounce pfn is equal
	 * to or bigger than the highest pfn in the system -- in that case,
	 * don't waste time iterating over bio segments
	 */
	if (!(q->bounce_gfp & GFP_DMA)) {
		if (q->limits.bounce_pfn >= blk_max_pfn)
			return;
		pool = &page_pool;
	} else {
		BUG_ON(!mempool_initialized(&isa_page_pool));
		pool = &isa_page_pool;
	}

	/*
	 * slow path
	 */
	__blk_queue_bounce(q, bio_orig, pool);
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
831058de DH	2	/* bounce buffer handling for block devices
	3	*
	4	* - Split from highmem.c
	5	*/
	6
b1de0d13 MH	7	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
b1de0d13 MH	8
831058de	9	#include <linux/mm.h>
b95f1b31	10	#include <linux/export.h>
831058de	11	#include <linux/swap.h>
5a0e3ad6	12	#include <linux/gfp.h>
831058de DH	13	#include <linux/bio.h>
	14	#include <linux/pagemap.h>
	15	#include <linux/mempool.h>
	16	#include <linux/blkdev.h>
66114cad	17	#include <linux/backing-dev.h>
831058de DH	18	#include <linux/init.h>
	19	#include <linux/hash.h>
	20	#include <linux/highmem.h>
3bcfeaf9	21	#include <linux/bootmem.h>
b1de0d13	22	#include <linux/printk.h>
831058de DH	23	#include <asm/tlbflush.h>
831058de DH	24
55782138	25	#include <trace/events/block.h>
3bce016a	26	#include "blk.h"
55782138	27
831058de DH	28	#define POOL_SIZE 64
	29	#define ISA_POOL_SIZE 16
	30
338aa96d KO	31	static struct bio_set bounce_bio_set, bounce_bio_split;
338aa96d KO	32	static mempool_t page_pool, isa_page_pool;
831058de	33
a687a533	34	#if defined(CONFIG_HIGHMEM)
831058de DH	35	static __init int init_emergency_pool(void)
831058de DH	36	{
338aa96d	37	int ret;
f1006257	38	#if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG)
3bcfeaf9	39	if (max_pfn <= max_low_pfn)
831058de	40	return 0;
3bcfeaf9	41	#endif
831058de	42
338aa96d KO	43	ret = mempool_init_page_pool(&page_pool, POOL_SIZE, 0);
338aa96d KO	44	BUG_ON(ret);
b1de0d13	45	pr_info("pool size: %d pages\n", POOL_SIZE);
831058de	46
338aa96d KO	47	ret = bioset_init(&bounce_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS);
338aa96d KO	48	BUG_ON(ret);
04c4950d	49	if (bioset_integrity_create(&bounce_bio_set, BIO_POOL_SIZE))
a8821f3f N	50	BUG_ON(1);
a8821f3f N	51
338aa96d KO	52	ret = bioset_init(&bounce_bio_split, BIO_POOL_SIZE, 0, 0);
338aa96d KO	53	BUG_ON(ret);
a8821f3f	54
831058de DH	55	return 0;
	56	}
	57
	58	__initcall(init_emergency_pool);
f1006257	59	#endif
831058de	60
f1006257	61	#ifdef CONFIG_HIGHMEM
831058de DH	62	/*
	63	* highmem version, map in to vec
	64	*/
	65	static void bounce_copy_vec(struct bio_vec to, unsigned char vfrom)
	66	{
831058de DH	67	unsigned char *vto;
831058de DH	68
9b04c5fe	69	vto = kmap_atomic(to->bv_page);
831058de	70	memcpy(vto + to->bv_offset, vfrom, to->bv_len);
9b04c5fe	71	kunmap_atomic(vto);
831058de DH	72	}
	73
	74	#else /* CONFIG_HIGHMEM */
	75
	76	#define bounce_copy_vec(to, vfrom) \
	77	memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
	78
	79	#endif /* CONFIG_HIGHMEM */
	80
	81	/*
	82	* allocate pages in the DMA region for the ISA pool
	83	*/
	84	static void mempool_alloc_pages_isa(gfp_t gfp_mask, void data)
	85	{
	86	return mempool_alloc_pages(gfp_mask \| GFP_DMA, data);
	87	}
	88
	89	/*
	90	* gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
	91	* as the max address, so check if the pool has already been created.
	92	*/
	93	int init_emergency_isa_pool(void)
	94	{
338aa96d KO	95	int ret;
	96
	97	if (mempool_initialized(&isa_page_pool))
831058de DH	98	return 0;
831058de DH	99
338aa96d KO	100	ret = mempool_init(&isa_page_pool, ISA_POOL_SIZE, mempool_alloc_pages_isa,
	101	mempool_free_pages, (void *) 0);
	102	BUG_ON(ret);
831058de	103
b1de0d13	104	pr_info("isa pool size: %d pages\n", ISA_POOL_SIZE);
831058de DH	105	return 0;
	106	}
	107
	108	/*
	109	* Simple bounce buffer support for highmem pages. Depending on the
	110	* queue gfp mask set, *to may or may not be a highmem page. kmap it
	111	* always, it will do the Right Thing
	112	*/
	113	static void copy_to_high_bio_irq(struct bio to, struct bio from)
	114	{
	115	unsigned char *vfrom;
3c892a09	116	struct bio_vec tovec, fromvec;
7988613b	117	struct bvec_iter iter;
3c892a09 ML	118	/*
	119	* The bio of @from is created by bounce, so we can iterate
	120	* its bvec from start to end, but the @from->bi_iter can't be
	121	* trusted because it might be changed by splitting.
	122	*/
	123	struct bvec_iter from_iter = BVEC_ITER_ALL_INIT;
7988613b KO	124
7988613b KO	125	bio_for_each_segment(tovec, to, iter) {
3c892a09 ML	126	fromvec = bio_iter_iovec(from, from_iter);
3c892a09 ML	127	if (tovec.bv_page != fromvec.bv_page) {
7988613b KO	128	/*
	129	* fromvec->bv_offset and fromvec->bv_len might have
	130	* been modified by the block layer, so use the original
	131	* copy, bounce_copy_vec already uses tovec->bv_len
	132	*/
3c892a09	133	vfrom = page_address(fromvec.bv_page) +
7988613b KO	134	tovec.bv_offset;
	135
	136	bounce_copy_vec(&tovec, vfrom);
	137	flush_dcache_page(tovec.bv_page);
	138	}
3c892a09	139	bio_advance_iter(from, &from_iter, tovec.bv_len);
831058de DH	140	}
	141	}
	142
4246a0b6	143	static void bounce_end_io(struct bio bio, mempool_t pool)
831058de DH	144	{
831058de DH	145	struct bio *bio_orig = bio->bi_private;
7891f05c	146	struct bio_vec *bvec, orig_vec;
831058de	147	int i;
7891f05c	148	struct bvec_iter orig_iter = bio_orig->bi_iter;
831058de	149
831058de DH	150	/*
	151	* free up bounce indirect pages used
	152	*/
d74c6d51	153	bio_for_each_segment_all(bvec, bio, i) {
7891f05c ML	154	orig_vec = bio_iter_iovec(bio_orig, orig_iter);
	155	if (bvec->bv_page != orig_vec.bv_page) {
	156	dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
	157	mempool_free(bvec->bv_page, pool);
	158	}
	159	bio_advance_iter(bio_orig, &orig_iter, orig_vec.bv_len);
831058de DH	160	}
831058de DH	161
4e4cbee9	162	bio_orig->bi_status = bio->bi_status;
4246a0b6	163	bio_endio(bio_orig);
831058de DH	164	bio_put(bio);
	165	}
	166
4246a0b6	167	static void bounce_end_io_write(struct bio *bio)
831058de	168	{
338aa96d	169	bounce_end_io(bio, &page_pool);
831058de DH	170	}
831058de DH	171
4246a0b6	172	static void bounce_end_io_write_isa(struct bio *bio)
831058de	173	{
831058de	174
338aa96d	175	bounce_end_io(bio, &isa_page_pool);
831058de DH	176	}
831058de DH	177
4246a0b6	178	static void __bounce_end_io_read(struct bio bio, mempool_t pool)
831058de DH	179	{
	180	struct bio *bio_orig = bio->bi_private;
	181
4e4cbee9	182	if (!bio->bi_status)
831058de DH	183	copy_to_high_bio_irq(bio_orig, bio);
831058de DH	184
4246a0b6	185	bounce_end_io(bio, pool);
831058de DH	186	}
831058de DH	187
4246a0b6	188	static void bounce_end_io_read(struct bio *bio)
831058de	189	{
338aa96d	190	__bounce_end_io_read(bio, &page_pool);
831058de DH	191	}
831058de DH	192
4246a0b6	193	static void bounce_end_io_read_isa(struct bio *bio)
831058de	194	{
338aa96d	195	__bounce_end_io_read(bio, &isa_page_pool);
831058de DH	196	}
831058de DH	197
c55183c9 CH	198	static struct bio bounce_clone_bio(struct bio bio_src, gfp_t gfp_mask,
	199	struct bio_set *bs)
	200	{
	201	struct bvec_iter iter;
	202	struct bio_vec bv;
	203	struct bio *bio;
	204
	205	/*
	206	* Pre immutable biovecs, __bio_clone() used to just do a memcpy from
	207	* bio_src->bi_io_vec to bio->bi_io_vec.
	208	*
	209	* We can't do that anymore, because:
	210	*
	211	* - The point of cloning the biovec is to produce a bio with a biovec
	212	* the caller can modify: bi_idx and bi_bvec_done should be 0.
	213	*
	214	* - The original bio could've had more than BIO_MAX_PAGES biovecs; if
	215	* we tried to clone the whole thing bio_alloc_bioset() would fail.
	216	* But the clone should succeed as long as the number of biovecs we
	217	* actually need to allocate is fewer than BIO_MAX_PAGES.
	218	*
	219	* - Lastly, bi_vcnt should not be looked at or relied upon by code
	220	* that does not own the bio - reason being drivers don't use it for
	221	* iterating over the biovec anymore, so expecting it to be kept up
	222	* to date (i.e. for clones that share the parent biovec) is just
	223	* asking for trouble and would force extra work on
	224	* __bio_clone_fast() anyways.
	225	*/
	226
	227	bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs);
	228	if (!bio)
	229	return NULL;
	230	bio->bi_disk = bio_src->bi_disk;
	231	bio->bi_opf = bio_src->bi_opf;
	232	bio->bi_write_hint = bio_src->bi_write_hint;
	233	bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector;
	234	bio->bi_iter.bi_size = bio_src->bi_iter.bi_size;
	235
	236	switch (bio_op(bio)) {
	237	case REQ_OP_DISCARD:
	238	case REQ_OP_SECURE_ERASE:
	239	case REQ_OP_WRITE_ZEROES:
	240	break;
	241	case REQ_OP_WRITE_SAME:
	242	bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0];
	243	break;
	244	default:
	245	bio_for_each_segment(bv, bio_src, iter)
	246	bio->bi_io_vec[bio->bi_vcnt++] = bv;
	247	break;
	248	}
	249
	250	if (bio_integrity(bio_src)) {
	251	int ret;
	252
	253	ret = bio_integrity_clone(bio, bio_src, gfp_mask);
	254	if (ret < 0) {
	255	bio_put(bio);
	256	return NULL;
	257	}
	258	}
	259
	260	bio_clone_blkcg_association(bio, bio_src);
	261
262	return bio;
263	}
264
165125e1	265	static void __blk_queue_bounce(struct request_queue q, struct bio *bio_orig,
a3ad0a9d	266	mempool_t *pool)
831058de	267	{
6bc454d1 KO	268	struct bio *bio;
6bc454d1 KO	269	int rw = bio_data_dir(*bio_orig);
7988613b KO	270	struct bio_vec *to, from;
7988613b KO	271	struct bvec_iter iter;
a8821f3f N	272	unsigned i = 0;
	273	bool bounce = false;
	274	int sectors = 0;
14cb0dc6	275	bool passthrough = bio_is_passthrough(*bio_orig);
831058de	276
a8821f3f N	277	bio_for_each_segment(from, *bio_orig, iter) {
	278	if (i++ < BIO_MAX_PAGES)
	279	sectors += from.bv_len >> 9;
1c4bc3ab	280	if (page_to_pfn(from.bv_page) > q->limits.bounce_pfn)
a8821f3f N	281	bounce = true;
	282	}
	283	if (!bounce)
	284	return;
	285
14cb0dc6	286	if (!passthrough && sectors < bio_sectors(*bio_orig)) {
338aa96d	287	bio = bio_split(*bio_orig, sectors, GFP_NOIO, &bounce_bio_split);
a8821f3f N	288	bio_chain(bio, *bio_orig);
	289	generic_make_request(*bio_orig);
	290	*bio_orig = bio;
	291	}
c55183c9	292	bio = bounce_clone_bio(*bio_orig, GFP_NOIO, passthrough ? NULL :
338aa96d	293	&bounce_bio_set);
831058de	294
cb34e057	295	bio_for_each_segment_all(to, bio, i) {
6bc454d1	296	struct page *page = to->bv_page;
f735b5ee	297
1c4bc3ab	298	if (page_to_pfn(page) <= q->limits.bounce_pfn)
6bc454d1	299	continue;
831058de	300
6bc454d1	301	to->bv_page = mempool_alloc(pool, q->bounce_gfp);
393a3397	302	inc_zone_page_state(to->bv_page, NR_BOUNCE);
831058de DH	303
	304	if (rw == WRITE) {
	305	char vto, vfrom;
	306
6bc454d1 KO	307	flush_dcache_page(page);
6bc454d1 KO	308
831058de	309	vto = page_address(to->bv_page) + to->bv_offset;
6bc454d1	310	vfrom = kmap_atomic(page) + to->bv_offset;
831058de	311	memcpy(vto, vfrom, to->bv_len);
6bc454d1	312	kunmap_atomic(vfrom);
831058de DH	313	}
	314	}
	315
5f3ea37c	316	trace_block_bio_bounce(q, *bio_orig);
c43a5082	317
831058de	318	bio->bi_flags \|= (1 << BIO_BOUNCED);
831058de	319
338aa96d	320	if (pool == &page_pool) {
831058de DH	321	bio->bi_end_io = bounce_end_io_write;
	322	if (rw == READ)
	323	bio->bi_end_io = bounce_end_io_read;
	324	} else {
	325	bio->bi_end_io = bounce_end_io_write_isa;
	326	if (rw == READ)
	327	bio->bi_end_io = bounce_end_io_read_isa;
	328	}
	329
	330	bio->bi_private = *bio_orig;
	331	*bio_orig = bio;
	332	}
	333
165125e1	334	void blk_queue_bounce(struct request_queue q, struct bio *bio_orig)
831058de DH	335	{
	336	mempool_t *pool;
	337
bf2de6f5 JA	338	/*
	339	* Data-less bio, nothing to bounce
	340	*/
36144077	341	if (!bio_has_data(*bio_orig))
bf2de6f5 JA	342	return;
bf2de6f5 JA	343
831058de DH	344	/*
	345	* for non-isa bounce case, just check if the bounce pfn is equal
	346	* to or bigger than the highest pfn in the system -- in that case,
	347	* don't waste time iterating over bio segments
	348	*/
	349	if (!(q->bounce_gfp & GFP_DMA)) {
1c4bc3ab	350	if (q->limits.bounce_pfn >= blk_max_pfn)
831058de	351	return;
338aa96d	352	pool = &page_pool;
831058de	353	} else {
338aa96d KO	354	BUG_ON(!mempool_initialized(&isa_page_pool));
338aa96d KO	355	pool = &isa_page_pool;
831058de DH	356	}
831058de DH	357
831058de DH	358	/*
	359	* slow path
	360	*/
a3ad0a9d	361	__blk_queue_bounce(q, bio_orig, pool);
831058de	362	}