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![Gary King](/assets/img/avatar_default.png)
I have been seeing problems on Tegra 2 (ARMv7 SMP) systems with HIGHMEM enabled on 2.6.35 (plus some patches targetted at 2.6.36 to perform cache maintenance lazily), and the root cause appears to be that the mm bouncing code is calling flush_dcache_page before it copies the bounce buffer into the bio. The bounced page needs to be flushed after data is copied into it, to ensure that architecture implementations can synchronize instruction and data caches if necessary. Signed-off-by: Gary King <gking@nvidia.com> Cc: Tejun Heo <tj@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Acked-by: Jens Axboe <axboe@kernel.dk> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
300 lines
6.5 KiB
C
300 lines
6.5 KiB
C
/* bounce buffer handling for block devices
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*
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* - Split from highmem.c
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*/
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/swap.h>
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#include <linux/gfp.h>
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#include <linux/bio.h>
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#include <linux/pagemap.h>
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#include <linux/mempool.h>
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#include <linux/blkdev.h>
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#include <linux/init.h>
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#include <linux/hash.h>
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#include <linux/highmem.h>
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#include <asm/tlbflush.h>
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#include <trace/events/block.h>
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#define POOL_SIZE 64
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#define ISA_POOL_SIZE 16
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static mempool_t *page_pool, *isa_page_pool;
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#ifdef CONFIG_HIGHMEM
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static __init int init_emergency_pool(void)
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{
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struct sysinfo i;
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si_meminfo(&i);
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si_swapinfo(&i);
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if (!i.totalhigh)
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return 0;
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page_pool = mempool_create_page_pool(POOL_SIZE, 0);
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BUG_ON(!page_pool);
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printk("highmem bounce pool size: %d pages\n", POOL_SIZE);
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return 0;
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}
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__initcall(init_emergency_pool);
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/*
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* highmem version, map in to vec
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*/
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static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
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{
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unsigned long flags;
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unsigned char *vto;
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local_irq_save(flags);
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vto = kmap_atomic(to->bv_page, KM_BOUNCE_READ);
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memcpy(vto + to->bv_offset, vfrom, to->bv_len);
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kunmap_atomic(vto, KM_BOUNCE_READ);
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local_irq_restore(flags);
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}
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#else /* CONFIG_HIGHMEM */
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#define bounce_copy_vec(to, vfrom) \
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memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
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#endif /* CONFIG_HIGHMEM */
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/*
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* allocate pages in the DMA region for the ISA pool
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*/
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static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data)
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{
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return mempool_alloc_pages(gfp_mask | GFP_DMA, data);
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}
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/*
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* gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
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* as the max address, so check if the pool has already been created.
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*/
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int init_emergency_isa_pool(void)
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{
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if (isa_page_pool)
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return 0;
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isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
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mempool_free_pages, (void *) 0);
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BUG_ON(!isa_page_pool);
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printk("isa bounce pool size: %d pages\n", ISA_POOL_SIZE);
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return 0;
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}
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/*
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* Simple bounce buffer support for highmem pages. Depending on the
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* queue gfp mask set, *to may or may not be a highmem page. kmap it
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* always, it will do the Right Thing
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*/
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static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
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{
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unsigned char *vfrom;
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struct bio_vec *tovec, *fromvec;
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int i;
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__bio_for_each_segment(tovec, to, i, 0) {
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fromvec = from->bi_io_vec + i;
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/*
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* not bounced
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*/
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if (tovec->bv_page == fromvec->bv_page)
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continue;
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/*
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* fromvec->bv_offset and fromvec->bv_len might have been
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* modified by the block layer, so use the original copy,
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* bounce_copy_vec already uses tovec->bv_len
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*/
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vfrom = page_address(fromvec->bv_page) + tovec->bv_offset;
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bounce_copy_vec(tovec, vfrom);
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flush_dcache_page(tovec->bv_page);
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}
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}
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static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
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{
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struct bio *bio_orig = bio->bi_private;
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struct bio_vec *bvec, *org_vec;
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int i;
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if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
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set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);
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/*
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* free up bounce indirect pages used
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*/
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__bio_for_each_segment(bvec, bio, i, 0) {
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org_vec = bio_orig->bi_io_vec + i;
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if (bvec->bv_page == org_vec->bv_page)
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continue;
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dec_zone_page_state(bvec->bv_page, NR_BOUNCE);
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mempool_free(bvec->bv_page, pool);
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}
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bio_endio(bio_orig, err);
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bio_put(bio);
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}
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static void bounce_end_io_write(struct bio *bio, int err)
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{
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bounce_end_io(bio, page_pool, err);
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}
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static void bounce_end_io_write_isa(struct bio *bio, int err)
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{
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bounce_end_io(bio, isa_page_pool, err);
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}
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static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err)
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{
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struct bio *bio_orig = bio->bi_private;
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if (test_bit(BIO_UPTODATE, &bio->bi_flags))
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copy_to_high_bio_irq(bio_orig, bio);
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bounce_end_io(bio, pool, err);
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}
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static void bounce_end_io_read(struct bio *bio, int err)
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{
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__bounce_end_io_read(bio, page_pool, err);
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}
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static void bounce_end_io_read_isa(struct bio *bio, int err)
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{
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__bounce_end_io_read(bio, isa_page_pool, err);
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}
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static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
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mempool_t *pool)
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{
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struct page *page;
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struct bio *bio = NULL;
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int i, rw = bio_data_dir(*bio_orig);
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struct bio_vec *to, *from;
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bio_for_each_segment(from, *bio_orig, i) {
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page = from->bv_page;
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/*
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* is destination page below bounce pfn?
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*/
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if (page_to_pfn(page) <= queue_bounce_pfn(q))
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continue;
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/*
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* irk, bounce it
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*/
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if (!bio) {
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unsigned int cnt = (*bio_orig)->bi_vcnt;
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bio = bio_alloc(GFP_NOIO, cnt);
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memset(bio->bi_io_vec, 0, cnt * sizeof(struct bio_vec));
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}
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to = bio->bi_io_vec + i;
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to->bv_page = mempool_alloc(pool, q->bounce_gfp);
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to->bv_len = from->bv_len;
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to->bv_offset = from->bv_offset;
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inc_zone_page_state(to->bv_page, NR_BOUNCE);
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if (rw == WRITE) {
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char *vto, *vfrom;
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flush_dcache_page(from->bv_page);
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vto = page_address(to->bv_page) + to->bv_offset;
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vfrom = kmap(from->bv_page) + from->bv_offset;
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memcpy(vto, vfrom, to->bv_len);
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kunmap(from->bv_page);
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}
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}
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/*
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* no pages bounced
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*/
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if (!bio)
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return;
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trace_block_bio_bounce(q, *bio_orig);
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/*
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* at least one page was bounced, fill in possible non-highmem
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* pages
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*/
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__bio_for_each_segment(from, *bio_orig, i, 0) {
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to = bio_iovec_idx(bio, i);
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if (!to->bv_page) {
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to->bv_page = from->bv_page;
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to->bv_len = from->bv_len;
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to->bv_offset = from->bv_offset;
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}
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}
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bio->bi_bdev = (*bio_orig)->bi_bdev;
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bio->bi_flags |= (1 << BIO_BOUNCED);
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bio->bi_sector = (*bio_orig)->bi_sector;
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bio->bi_rw = (*bio_orig)->bi_rw;
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bio->bi_vcnt = (*bio_orig)->bi_vcnt;
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bio->bi_idx = (*bio_orig)->bi_idx;
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bio->bi_size = (*bio_orig)->bi_size;
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if (pool == page_pool) {
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bio->bi_end_io = bounce_end_io_write;
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if (rw == READ)
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bio->bi_end_io = bounce_end_io_read;
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} else {
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bio->bi_end_io = bounce_end_io_write_isa;
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if (rw == READ)
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bio->bi_end_io = bounce_end_io_read_isa;
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}
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bio->bi_private = *bio_orig;
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*bio_orig = bio;
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}
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void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
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{
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mempool_t *pool;
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/*
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* Data-less bio, nothing to bounce
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*/
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if (!bio_has_data(*bio_orig))
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return;
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/*
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* for non-isa bounce case, just check if the bounce pfn is equal
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* to or bigger than the highest pfn in the system -- in that case,
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* don't waste time iterating over bio segments
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*/
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if (!(q->bounce_gfp & GFP_DMA)) {
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if (queue_bounce_pfn(q) >= blk_max_pfn)
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return;
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pool = page_pool;
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} else {
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BUG_ON(!isa_page_pool);
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pool = isa_page_pool;
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}
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/*
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* slow path
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*/
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__blk_queue_bounce(q, bio_orig, pool);
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}
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EXPORT_SYMBOL(blk_queue_bounce);
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