From 6bc454d150047fcfbf53346412e64cdf3bf61a79 Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Mon, 10 Sep 2012 14:30:37 -0700 Subject: [PATCH] bounce: Refactor __blk_queue_bounce to not use bi_io_vec A bunch of what __blk_queue_bounce() was doing was problematic for the immutable bvec work; this cleans that up and the code is quite a bit smaller, too. The __bio_for_each_segment() in copy_to_high_bio_irq() was changed because that one's looping over the original bio, not the bounce bio - a later patch renames __bio_for_each_segment() -> bio_for_each_segment_all(), and documents that bio_for_each_segment_all() is only for code that owns the bio. Signed-off-by: Kent Overstreet CC: Jens Axboe --- mm/bounce.c | 73 ++++++++++++++++--------------------------------------------- 1 file changed, 19 insertions(+), 54 deletions(-) diff --git a/mm/bounce.c b/mm/bounce.c index 5f89017..55f512a 100644 --- a/mm/bounce.c +++ b/mm/bounce.c @@ -101,7 +101,7 @@ static void copy_to_high_bio_irq(struct bio *to, struct bio *from) struct bio_vec *tovec, *fromvec; int i; - __bio_for_each_segment(tovec, to, i, 0) { + bio_for_each_segment(tovec, to, i) { fromvec = from->bi_io_vec + i; /* @@ -218,78 +218,43 @@ static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio) static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig, mempool_t *pool, int force) { - struct page *page; - struct bio *bio = NULL; - int i, rw = bio_data_dir(*bio_orig); + struct bio *bio; + int rw = bio_data_dir(*bio_orig); struct bio_vec *to, *from; + unsigned i; - bio_for_each_segment(from, *bio_orig, i) { - page = from->bv_page; + bio_for_each_segment(from, *bio_orig, i) + if (page_to_pfn(from->bv_page) > queue_bounce_pfn(q)) + goto bounce; - /* - * is destination page below bounce pfn? - */ - if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force) - continue; + return; +bounce: + bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set); - /* - * irk, bounce it - */ - if (!bio) { - unsigned int cnt = (*bio_orig)->bi_vcnt; - - bio = bio_alloc(GFP_NOIO, cnt); - memset(bio->bi_io_vec, 0, cnt * sizeof(struct bio_vec)); - } - + bio_for_each_segment(to, bio, i) { + struct page *page = to->bv_page; - to = bio->bi_io_vec + i; + if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force) + continue; - 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); + to->bv_page = mempool_alloc(pool, q->bounce_gfp); if (rw == WRITE) { char *vto, *vfrom; - flush_dcache_page(from->bv_page); + flush_dcache_page(page); + vto = page_address(to->bv_page) + to->bv_offset; - vfrom = kmap(from->bv_page) + from->bv_offset; + vfrom = kmap_atomic(page) + to->bv_offset; memcpy(vto, vfrom, to->bv_len); - kunmap(from->bv_page); + kunmap_atomic(vfrom); } } - /* - * no pages bounced - */ - if (!bio) - return; - trace_block_bio_bounce(q, *bio_orig); - /* - * 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; -- 2.7.4