mm/bounce.c - kernel/msm - Gitiles

 /* bounce buffer handling for block devices
  *
  * - Split from highmem.c
  */

 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/swap.h>
 #include <linux/bio.h>
 #include <linux/pagemap.h>
 #include <linux/mempool.h>
 #include <linux/blkdev.h>
 #include <linux/init.h>
 #include <linux/hash.h>
 #include <linux/highmem.h>
 #include <linux/blktrace_api.h>
 #include <asm/tlbflush.h>

 #define POOL_SIZE	64
 #define ISA_POOL_SIZE	16

 static mempool_t *page_pool, *isa_page_pool;

 #ifdef CONFIG_HIGHMEM
 static __init int init_emergency_pool(void)
 {
 	struct sysinfo i;
 	si_meminfo(&i);
 	si_swapinfo(&i);

 	if (!i.totalhigh)
 		return 0;

 	page_pool = mempool_create_page_pool(POOL_SIZE, 0);
 	BUG_ON(!page_pool);
 	printk("highmem bounce pool size: %d pages\n", POOL_SIZE);

 	return 0;
 }

 __initcall(init_emergency_pool);

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

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

 #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)
 {
 	if (isa_page_pool)
 		return 0;

 	isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
 				       mempool_free_pages, (void *) 0);
 	BUG_ON(!isa_page_pool);

 	printk("isa bounce 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;
 	int i;

 	__bio_for_each_segment(tovec, to, i, 0) {
 		fromvec = from->bi_io_vec + i;

 		/*
 		 * not bounced
 		 */
 		if (tovec->bv_page == fromvec->bv_page)
 			continue;

 		/*
 		 * 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;

 		flush_dcache_page(tovec->bv_page);
 		bounce_copy_vec(tovec, vfrom);
 	}
 }

 static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
 {
 	struct bio *bio_orig = bio->bi_private;
 	struct bio_vec *bvec, *org_vec;
 	int i;

 	if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
 		set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);

 	/*
 	 * free up bounce indirect pages used
 	 */
 	__bio_for_each_segment(bvec, bio, i, 0) {
 		org_vec = bio_orig->bi_io_vec + i;
 		if (bvec->bv_page == org_vec->bv_page)
 			continue;

 		dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
 		mempool_free(bvec->bv_page, pool);
 	}

 	bio_endio(bio_orig, bio_orig->bi_size, err);
 	bio_put(bio);
 }

 static int bounce_end_io_write(struct bio *bio, unsigned int bytes_done, int err)
 {
 	if (bio->bi_size)
 		return 1;

 	bounce_end_io(bio, page_pool, err);
 	return 0;
 }

 static int bounce_end_io_write_isa(struct bio *bio, unsigned int bytes_done, int err)
 {
 	if (bio->bi_size)
 		return 1;

 	bounce_end_io(bio, isa_page_pool, err);
 	return 0;
 }

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

 	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
 		copy_to_high_bio_irq(bio_orig, bio);

 	bounce_end_io(bio, pool, err);
 }

 static int bounce_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
 {
 	if (bio->bi_size)
 		return 1;

 	__bounce_end_io_read(bio, page_pool, err);
 	return 0;
 }

 static int bounce_end_io_read_isa(struct bio *bio, unsigned int bytes_done, int err)
 {
 	if (bio->bi_size)
 		return 1;

 	__bounce_end_io_read(bio, isa_page_pool, err);
 	return 0;
 }

 static void __blk_queue_bounce(request_queue_t *q, struct bio **bio_orig,
 			       mempool_t *pool)
 {
 	struct page *page;
 	struct bio *bio = NULL;
 	int i, rw = bio_data_dir(*bio_orig);
 	struct bio_vec *to, *from;

 	bio_for_each_segment(from, *bio_orig, i) {
 		page = from->bv_page;

 		/*
 		 * is destination page below bounce pfn?
 		 */
 		if (page_to_pfn(page) < q->bounce_pfn)
 			continue;

 		/*
 		 * irk, bounce it
 		 */
 		if (!bio)
 			bio = bio_alloc(GFP_NOIO, (*bio_orig)->bi_vcnt);

 		to = bio->bi_io_vec + i;

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

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

 			flush_dcache_page(from->bv_page);
 			vto = page_address(to->bv_page) + to->bv_offset;
 			vfrom = kmap(from->bv_page) + from->bv_offset;
 			memcpy(vto, vfrom, to->bv_len);
 			kunmap(from->bv_page);
 		}
 	}

 	/*
 	 * no pages bounced
 	 */
 	if (!bio)
 		return;

 	/*
 	 * at least one page was bounced, fill in possible non-highmem
 	 * pages
 	 */
 	__bio_for_each_segment(from, *bio_orig, i, 0) {
 		to = bio_iovec_idx(bio, i);
 		if (!to->bv_page) {
 			to->bv_page = from->bv_page;
 			to->bv_len = from->bv_len;
 			to->bv_offset = from->bv_offset;
 		}
 	}

 	bio->bi_bdev = (*bio_orig)->bi_bdev;
 	bio->bi_flags |= (1 << BIO_BOUNCED);
 	bio->bi_sector = (*bio_orig)->bi_sector;
 	bio->bi_rw = (*bio_orig)->bi_rw;

 	bio->bi_vcnt = (*bio_orig)->bi_vcnt;
 	bio->bi_idx = (*bio_orig)->bi_idx;
 	bio->bi_size = (*bio_orig)->bi_size;

 	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(request_queue_t *q, struct bio **bio_orig)
 {
 	mempool_t *pool;

 	/*
 	 * 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->bounce_pfn >= blk_max_pfn)
 			return;
 		pool = page_pool;
 	} else {
 		BUG_ON(!isa_page_pool);
 		pool = isa_page_pool;
 	}

 	blk_add_trace_bio(q, *bio_orig, BLK_TA_BOUNCE);

 	/*
 	 * slow path
 	 */
 	__blk_queue_bounce(q, bio_orig, pool);
 }

 EXPORT_SYMBOL(blk_queue_bounce);
	/* bounce buffer handling for block devices
	*
	* - Split from highmem.c
	*/

	#include <linux/mm.h>
	#include <linux/module.h>
	#include <linux/swap.h>
	#include <linux/bio.h>
	#include <linux/pagemap.h>
	#include <linux/mempool.h>
	#include <linux/blkdev.h>
	#include <linux/init.h>
	#include <linux/hash.h>
	#include <linux/highmem.h>
	#include <linux/blktrace_api.h>
	#include <asm/tlbflush.h>

	#define POOL_SIZE 64
	#define ISA_POOL_SIZE 16

	static mempool_t page_pool, isa_page_pool;

	#ifdef CONFIG_HIGHMEM
	static __init int init_emergency_pool(void)
	{
	struct sysinfo i;
	si_meminfo(&i);
	si_swapinfo(&i);

	if (!i.totalhigh)
	return 0;

	page_pool = mempool_create_page_pool(POOL_SIZE, 0);
	BUG_ON(!page_pool);
	printk("highmem bounce pool size: %d pages\n", POOL_SIZE);

	return 0;
	}

	__initcall(init_emergency_pool);

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

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

	#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)
	{
	if (isa_page_pool)
	return 0;

	isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
	mempool_free_pages, (void *) 0);
	BUG_ON(!isa_page_pool);

	printk("isa bounce 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;
	int i;

	__bio_for_each_segment(tovec, to, i, 0) {
	fromvec = from->bi_io_vec + i;

	/*
	* not bounced
	*/
	if (tovec->bv_page == fromvec->bv_page)
	continue;

	/*
	* 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;

	flush_dcache_page(tovec->bv_page);
	bounce_copy_vec(tovec, vfrom);
	}
	}

	static void bounce_end_io(struct bio bio, mempool_t pool, int err)
	{
	struct bio *bio_orig = bio->bi_private;
	struct bio_vec bvec, org_vec;
	int i;

	if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
	set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);

	/*
	* free up bounce indirect pages used
	*/
	__bio_for_each_segment(bvec, bio, i, 0) {
	org_vec = bio_orig->bi_io_vec + i;
	if (bvec->bv_page == org_vec->bv_page)
	continue;

	dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
	mempool_free(bvec->bv_page, pool);
	}

	bio_endio(bio_orig, bio_orig->bi_size, err);
	bio_put(bio);
	}

	static int bounce_end_io_write(struct bio *bio, unsigned int bytes_done, int err)
	{
	if (bio->bi_size)
	return 1;

	bounce_end_io(bio, page_pool, err);
	return 0;
	}

	static int bounce_end_io_write_isa(struct bio *bio, unsigned int bytes_done, int err)
	{
	if (bio->bi_size)
	return 1;

	bounce_end_io(bio, isa_page_pool, err);
	return 0;
	}

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

	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
	copy_to_high_bio_irq(bio_orig, bio);

	bounce_end_io(bio, pool, err);
	}

	static int bounce_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
	{
	if (bio->bi_size)
	return 1;

	__bounce_end_io_read(bio, page_pool, err);
	return 0;
	}

	static int bounce_end_io_read_isa(struct bio *bio, unsigned int bytes_done, int err)
	{
	if (bio->bi_size)
	return 1;

	__bounce_end_io_read(bio, isa_page_pool, err);
	return 0;
	}

	static void __blk_queue_bounce(request_queue_t q, struct bio *bio_orig,
	mempool_t *pool)
	{
	struct page *page;
	struct bio *bio = NULL;
	int i, rw = bio_data_dir(*bio_orig);
	struct bio_vec to, from;

	bio_for_each_segment(from, *bio_orig, i) {
	page = from->bv_page;

	/*
	* is destination page below bounce pfn?
	*/
	if (page_to_pfn(page) < q->bounce_pfn)
	continue;

	/*
	* irk, bounce it
	*/
	if (!bio)
	bio = bio_alloc(GFP_NOIO, (*bio_orig)->bi_vcnt);

	to = bio->bi_io_vec + i;

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

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

	flush_dcache_page(from->bv_page);
	vto = page_address(to->bv_page) + to->bv_offset;
	vfrom = kmap(from->bv_page) + from->bv_offset;
	memcpy(vto, vfrom, to->bv_len);
	kunmap(from->bv_page);
	}
	}

	/*
	* no pages bounced
	*/
	if (!bio)
	return;

	/*
	* at least one page was bounced, fill in possible non-highmem
	* pages
	*/
	__bio_for_each_segment(from, *bio_orig, i, 0) {
	to = bio_iovec_idx(bio, i);
	if (!to->bv_page) {
	to->bv_page = from->bv_page;
	to->bv_len = from->bv_len;
	to->bv_offset = from->bv_offset;
	}
	}

	bio->bi_bdev = (*bio_orig)->bi_bdev;
	bio->bi_flags \|= (1 << BIO_BOUNCED);
	bio->bi_sector = (*bio_orig)->bi_sector;
	bio->bi_rw = (*bio_orig)->bi_rw;

	bio->bi_vcnt = (*bio_orig)->bi_vcnt;
	bio->bi_idx = (*bio_orig)->bi_idx;
	bio->bi_size = (*bio_orig)->bi_size;

	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(request_queue_t q, struct bio *bio_orig)
	{
	mempool_t *pool;

	/*
	* 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->bounce_pfn >= blk_max_pfn)
	return;
	pool = page_pool;
	} else {
	BUG_ON(!isa_page_pool);
	pool = isa_page_pool;
	}

	blk_add_trace_bio(q, *bio_orig, BLK_TA_BOUNCE);

	/*
	* slow path
	*/
	__blk_queue_bounce(q, bio_orig, pool);
	}

	EXPORT_SYMBOL(blk_queue_bounce);