diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/Makefile | 1 | ||||
| -rw-r--r-- | block/bounce.c | 287 |
2 files changed, 288 insertions, 0 deletions
diff --git a/block/Makefile b/block/Makefile index b4c4d3b99a2..a2ce6ac935e 100644 --- a/block/Makefile +++ b/block/Makefile @@ -10,6 +10,7 @@ obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-tag.o blk-sysfs.o \ genhd.o scsi_ioctl.o partition-generic.o ioprio.o \ partitions/ +obj-$(CONFIG_BOUNCE) += bounce.o obj-$(CONFIG_BLK_DEV_BSG) += bsg.o obj-$(CONFIG_BLK_DEV_BSGLIB) += bsg-lib.o obj-$(CONFIG_BLK_CGROUP) += blk-cgroup.o diff --git a/block/bounce.c b/block/bounce.c new file mode 100644 index 00000000000..523918b8c6d --- /dev/null +++ b/block/bounce.c @@ -0,0 +1,287 @@ +/* bounce buffer handling for block devices + * + * - Split from highmem.c + */ + +#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/init.h> +#include <linux/hash.h> +#include <linux/highmem.h> +#include <linux/bootmem.h> +#include <asm/tlbflush.h> + +#include <trace/events/block.h> + +#define POOL_SIZE 64 +#define ISA_POOL_SIZE 16 + +static mempool_t *page_pool, *isa_page_pool; + +#if defined(CONFIG_HIGHMEM) || defined(CONFIG_NEED_BOUNCE_POOL) +static __init int init_emergency_pool(void) +{ +#if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG) + if (max_pfn <= max_low_pfn) + return 0; +#endif + + page_pool = mempool_create_page_pool(POOL_SIZE, 0); + BUG_ON(!page_pool); + printk("bounce pool size: %d pages\n", POOL_SIZE); + + 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 long flags; + unsigned char *vto; + + local_irq_save(flags); + vto = kmap_atomic(to->bv_page); + memcpy(vto + to->bv_offset, vfrom, to->bv_len); + kunmap_atomic(vto); + 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 = from->bi_io_vec; + struct bvec_iter iter; + + bio_for_each_segment(tovec, to, 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); + } + + fromvec++; + } +} + +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_all(bvec, bio, i) { + 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, err); + bio_put(bio); +} + +static void bounce_end_io_write(struct bio *bio, int err) +{ + bounce_end_io(bio, page_pool, err); +} + +static void bounce_end_io_write_isa(struct bio *bio, int err) +{ + + bounce_end_io(bio, isa_page_pool, err); +} + +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 void bounce_end_io_read(struct bio *bio, int err) +{ + __bounce_end_io_read(bio, page_pool, err); +} + +static void bounce_end_io_read_isa(struct bio *bio, int err) +{ + __bounce_end_io_read(bio, isa_page_pool, err); +} + +#ifdef CONFIG_NEED_BOUNCE_POOL +static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio) +{ + if (bio_data_dir(bio) != WRITE) + return 0; + + if (!bdi_cap_stable_pages_required(&q->backing_dev_info)) + return 0; + + return test_bit(BIO_SNAP_STABLE, &bio->bi_flags); +} +#else +static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio) +{ + return 0; +} +#endif /* CONFIG_NEED_BOUNCE_POOL */ + +static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig, + mempool_t *pool, int force) +{ + struct bio *bio; + int rw = bio_data_dir(*bio_orig); + struct bio_vec *to, from; + struct bvec_iter iter; + unsigned i; + + if (force) + goto bounce; + bio_for_each_segment(from, *bio_orig, iter) + if (page_to_pfn(from.bv_page) > queue_bounce_pfn(q)) + goto bounce; + + return; +bounce: + bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set); + + bio_for_each_segment_all(to, bio, i) { + struct page *page = to->bv_page; + + if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force) + continue; + + inc_zone_page_state(to->bv_page, NR_BOUNCE); + to->bv_page = mempool_alloc(pool, q->bounce_gfp); + + 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) +{ + int must_bounce; + mempool_t *pool; + + /* + * Data-less bio, nothing to bounce + */ + if (!bio_has_data(*bio_orig)) + return; + + must_bounce = must_snapshot_stable_pages(q, *bio_orig); + + /* + * 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 (queue_bounce_pfn(q) >= blk_max_pfn && !must_bounce) + return; + pool = page_pool; + } else { + BUG_ON(!isa_page_pool); + pool = isa_page_pool; + } + + /* + * slow path + */ + __blk_queue_bounce(q, bio_orig, pool, must_bounce); +} + +EXPORT_SYMBOL(blk_queue_bounce); |