Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753473Ab3FICUS (ORCPT ); Sat, 8 Jun 2013 22:20:18 -0400 Received: from mail-pb0-f48.google.com ([209.85.160.48]:45925 "EHLO mail-pb0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753366Ab3FICUL (ORCPT ); Sat, 8 Jun 2013 22:20:11 -0400 From: Kent Overstreet To: axboe@kernel.dk, tytso@mit.edu, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: Kent Overstreet Subject: [PATCH 25/26] block: Add bio_get_user_pages() Date: Sat, 8 Jun 2013 19:19:07 -0700 Message-Id: <1370744348-15407-26-git-send-email-koverstreet@google.com> X-Mailer: git-send-email 1.8.3.rc1 In-Reply-To: <1370744348-15407-1-git-send-email-koverstreet@google.com> References: <1370744348-15407-1-git-send-email-koverstreet@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5360 Lines: 194 This replaces some of the code that was in __bio_map_user_iov(), and soon we're going to use this helper in the dio code. Note that this relies on the recent change to make generic_make_request() take arbitrary sized bios - we're not using bio_add_page() here. Signed-off-by: Kent Overstreet Cc: Jens Axboe --- fs/bio.c | 123 +++++++++++++++++++++++++++------------------------- include/linux/bio.h | 2 + 2 files changed, 66 insertions(+), 59 deletions(-) diff --git a/fs/bio.c b/fs/bio.c index 10d71cf..fe88f6e 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -1212,17 +1212,69 @@ struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data, } EXPORT_SYMBOL(bio_copy_user); +/** + * bio_get_user_pages - pin user pages and add them to a biovec + * @bio: bio to add pages to + * @uaddr: start of user address + * @len: length in bytes + * @write_to_vm: bool indicating writing to pages or not + * + * Pins pages for up to @len bytes and appends them to @bio's bvec array. May + * pin only part of the requested pages - @bio need not have room for all the + * pages and can already have had pages added to it. + * + * Returns the number of bytes from @len added to @bio. + */ +ssize_t bio_get_user_pages(struct bio *bio, unsigned long uaddr, + unsigned long len, int write_to_vm) +{ + int ret; + unsigned nr_pages, bytes; + unsigned offset = offset_in_page(uaddr); + struct bio_vec *bv; + struct page **pages; + + nr_pages = min_t(size_t, + DIV_ROUND_UP(len + offset, PAGE_SIZE), + bio->bi_max_vecs - bio->bi_vcnt); + + bv = &bio->bi_io_vec[bio->bi_vcnt]; + pages = (void *) bv; + + ret = get_user_pages_fast(uaddr, nr_pages, write_to_vm, pages); + if (ret < 0) + return ret; + + bio->bi_vcnt += ret; + bytes = ret * PAGE_SIZE - offset; + + while (ret--) { + bv[ret].bv_page = pages[ret]; + bv[ret].bv_len = PAGE_SIZE; + bv[ret].bv_offset = 0; + } + + bv[0].bv_offset += offset; + bv[0].bv_len -= offset; + + if (bytes > len) { + bio->bi_io_vec[bio->bi_vcnt - 1].bv_len -= bytes - len; + bytes = len; + } + + bio->bi_iter.bi_size += bytes; + + return bytes; +} + static struct bio *__bio_map_user_iov(struct request_queue *q, struct block_device *bdev, struct sg_iovec *iov, int iov_count, int write_to_vm, gfp_t gfp_mask) { - int i, j; - int nr_pages = 0; - struct page **pages; + ssize_t ret; + int i, nr_pages = 0; struct bio *bio; - int cur_page = 0; - int ret, offset; for (i = 0; i < iov_count; i++) { unsigned long uaddr = (unsigned long)iov[i].iov_base; @@ -1251,57 +1303,17 @@ static struct bio *__bio_map_user_iov(struct request_queue *q, if (!bio) return ERR_PTR(-ENOMEM); - ret = -ENOMEM; - pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask); - if (!pages) - goto out; - for (i = 0; i < iov_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; - - ret = get_user_pages_fast(uaddr, local_nr_pages, - write_to_vm, &pages[cur_page]); - if (ret < local_nr_pages) { - ret = -EFAULT; - goto out_unmap; - } - - offset = uaddr & ~PAGE_MASK; - for (j = cur_page; j < page_limit; j++) { - unsigned int bytes = PAGE_SIZE - offset; + ret = bio_get_user_pages(bio, (size_t) iov[i].iov_base, + iov[i].iov_len, + write_to_vm); + if (ret < 0) + goto out; - if (len <= 0) - break; - - if (bytes > len) - bytes = len; - - /* - * sorry... - */ - if (bio_add_pc_page(q, bio, pages[j], bytes, offset) < - bytes) - break; - - 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++]); + if (ret != iov[i].iov_len) + break; } - kfree(pages); - /* * set data direction, and check if mapped pages need bouncing */ @@ -1312,14 +1324,7 @@ static struct bio *__bio_map_user_iov(struct request_queue *q, bio->bi_flags |= (1 << BIO_USER_MAPPED); return bio; - out_unmap: - for (i = 0; i < nr_pages; i++) { - if(!pages[i]) - break; - page_cache_release(pages[i]); - } out: - kfree(pages); bio_put(bio); return ERR_PTR(ret); } diff --git a/include/linux/bio.h b/include/linux/bio.h index 444cc91..340d859 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -333,6 +333,8 @@ extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int); extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *, unsigned int, unsigned int); extern int bio_get_nr_vecs(struct block_device *); +extern ssize_t bio_get_user_pages(struct bio *, unsigned long, + unsigned long, int); extern struct bio *bio_map_user(struct request_queue *, struct block_device *, unsigned long, unsigned int, int, gfp_t); struct sg_iovec; -- 1.8.3.rc1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/