-#define ISA_POOL_SIZE 16
-
-/*
- * 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, page_pool_alloc, page_pool_free, (void *) __GFP_DMA);
- if (!isa_page_pool)
- BUG();
-
- 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) {
- 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;
-
- bounce_copy_vec(tovec, vfrom);
- }
-}
-
-static void bounce_end_io(struct bio *bio, mempool_t *pool)
-{
- struct bio *bio_orig = bio->bi_private;
- struct bio_vec *bvec, *org_vec;
- int i;
-
- if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
- goto out_eio;
-
- set_bit(BIO_UPTODATE, &bio_orig->bi_flags);
-
- /*
- * free up bounce indirect pages used
- */
- bio_for_each_segment(bvec, bio, i) {
- org_vec = bio_orig->bi_io_vec + i;
- if (bvec->bv_page == org_vec->bv_page)
- continue;
-
- mempool_free(bvec->bv_page, pool);
- }
-
-out_eio:
- bio_endio(bio_orig, bio_orig->bi_size, 0);
- 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);
- 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);
- return 0;
-}
-
-static void __bounce_end_io_read(struct bio *bio, mempool_t *pool)
-{
- 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);
-}
-
-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);
- 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);
- 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;
-
- if (rw == WRITE) {
- char *vto, *vfrom;
-
- 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) {
- 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;
- }
-
- /*
- * slow path
- */
- __blk_queue_bounce(q, bio_orig, pool);
-}
-
-EXPORT_SYMBOL(blk_queue_bounce);
-