Messages in this thread Patch in this message | | | From | Tejun Heo <> | Subject | [PATCH 10/17] bio: use bio_create_from_sgl() in bio_map_user_iov() | Date | Wed, 1 Apr 2009 22:44:25 +0900 |
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Impact: cleanup
As bio_map_user_iov() is unique in the way it acquires pages to map from all other three operations (user-copy, kern-map, kern-copy), the function still needs to get the pages itself but the bio creation can use bio_create_from_sgl(). Create sgl of mapped pages and use it to create bio from it. The code will be further simplified with future changes to bio_create_from_sgl().
Signed-off-by: Tejun Heo <tj@kernel.org> --- fs/bio.c | 79 ++++++++++++++++++++++++++------------------------------------ 1 files changed, 33 insertions(+), 46 deletions(-)
diff --git a/fs/bio.c b/fs/bio.c index 4540afc..1ca8b16 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -1059,13 +1059,13 @@ struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *md, struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev, struct iovec *iov, int count, int rw, gfp_t gfp) { - int i, j; size_t tot_len = 0; int nr_pages = 0; + int nents = 0; + struct scatterlist *sgl; struct page **pages; struct bio *bio; - int cur_page = 0; - int ret, offset; + int i, ret; for (i = 0; i < count; i++) { unsigned long uaddr = (unsigned long)iov[i].iov_base; @@ -1088,70 +1088,57 @@ struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev, if (!nr_pages || tot_len & q->dma_pad_mask) return ERR_PTR(-EINVAL); - bio = bio_kmalloc(gfp, nr_pages); - if (!bio) + sgl = kmalloc(nr_pages * sizeof(sgl[0]), gfp); + if (!sgl) return ERR_PTR(-ENOMEM); + sg_init_table(sgl, nr_pages); ret = -ENOMEM; - pages = kcalloc(nr_pages, sizeof(struct page *), gfp); + pages = kcalloc(nr_pages, sizeof(pages[0]), gfp); if (!pages) - goto out; + goto err_sgl; for (i = 0; i < count; i++) { unsigned long uaddr = (unsigned long)iov[i].iov_base; unsigned long len = iov[i].iov_len; - unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; - unsigned long start = uaddr >> PAGE_SHIFT; - const int local_nr_pages = end - start; - const int page_limit = cur_page + local_nr_pages; - + unsigned long offset = offset_in_page(uaddr); + int local_nr_pages = PFN_UP(uaddr + len) - PFN_DOWN(uaddr); + ret = get_user_pages_fast(uaddr, local_nr_pages, rw == READ, - &pages[cur_page]); + &pages[nents]); if (ret < local_nr_pages) { ret = -EFAULT; - goto out_unmap; + goto err_pages; } - offset = uaddr & ~PAGE_MASK; - for (j = cur_page; j < page_limit; j++) { - unsigned int bytes = PAGE_SIZE - offset; + while (len) { + unsigned int bytes = min(PAGE_SIZE - offset, len); - if (len <= 0) - break; - - if (bytes > len) - bytes = len; - - /* - * sorry... - */ - if (bio_add_pc_page(q, bio, pages[j], bytes, offset) < - bytes) - break; + sg_set_page(&sgl[nents], pages[nents], bytes, offset); + nents++; len -= bytes; offset = 0; } - - cur_page = j; - /* - * release the pages we didn't map into the bio, if any - */ - while (j < page_limit) - page_cache_release(pages[j++]); } + BUG_ON(nents != nr_pages); - kfree(pages); + bio = bio_create_from_sgl(q, sgl, nents, nr_pages, rw, gfp); + if (IS_ERR(bio)) { + ret = PTR_ERR(bio); + goto err_pages; + } - /* - * set data direction, and check if mapped pages need bouncing - */ - if (rw == WRITE) - bio->bi_rw |= (1 << BIO_RW); + /* release the pages we didn't map into the bio, if any */ + for (i = bio->bi_vcnt; i < nr_pages; i++) + page_cache_release(pages[i]); bio->bi_bdev = bdev; bio->bi_flags |= (1 << BIO_USER_MAPPED); + kfree(sgl); + kfree(pages); + /* * subtle -- if __bio_map_user() ended up bouncing a bio, * it would normally disappear when its bi_end_io is run. @@ -1162,15 +1149,15 @@ struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev, return bio; - out_unmap: +err_pages: for (i = 0; i < nr_pages; i++) { - if(!pages[i]) + if (!pages[i]) break; page_cache_release(pages[i]); } - out: kfree(pages); - bio_put(bio); +err_sgl: + kfree(sgl); return ERR_PTR(ret); } -- 1.6.0.2
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