From 9124d3fe21b0947b03f4b87bcfb7acd675d6e85b Mon Sep 17 00:00:00 2001 From: Dongsu Park Date: Sun, 18 Jan 2015 16:16:34 +0100 Subject: block: rewrite and split __bio_copy_iov() Rewrite __bio_copy_iov using the copy_page_{from,to}_iter helpers, and split it into two simpler functions. This commit should contain only literal replacements, without functional changes. Cc: Kent Overstreet Cc: Jens Axboe Cc: Al Viro Signed-off-by: Dongsu Park [hch: removed the __bio_copy_iov wrapper] Signed-off-by: Christoph Hellwig Reviewed-by: Ming Lei Signed-off-by: Jens Axboe --- block/bio.c | 90 ++++++++++++++++++++++++++++++++++++++----------------------- 1 file changed, 56 insertions(+), 34 deletions(-) (limited to 'block') diff --git a/block/bio.c b/block/bio.c index 0723d4ce8589..f66a4eae16ee 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1036,43 +1036,66 @@ static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count, sizeof(struct iovec) * iov_count, gfp_mask); } -static int __bio_copy_iov(struct bio *bio, const struct iov_iter *iter, - int to_user, int from_user) +/** + * bio_copy_from_iter - copy all pages from iov_iter to bio + * @bio: The &struct bio which describes the I/O as destination + * @iter: iov_iter as source + * + * Copy all pages from iov_iter to bio. + * Returns 0 on success, or error on failure. + */ +static int bio_copy_from_iter(struct bio *bio, struct iov_iter iter) { - int ret = 0, i; + int i; struct bio_vec *bvec; - struct iov_iter iov_iter = *iter; bio_for_each_segment_all(bvec, bio, i) { - char *bv_addr = page_address(bvec->bv_page); - unsigned int bv_len = bvec->bv_len; - - while (bv_len && iov_iter.count) { - struct iovec iov = iov_iter_iovec(&iov_iter); - unsigned int bytes = min_t(unsigned int, bv_len, - iov.iov_len); - - if (!ret) { - if (to_user) - ret = copy_to_user(iov.iov_base, - bv_addr, bytes); - - if (from_user) - ret = copy_from_user(bv_addr, - iov.iov_base, - bytes); - - if (ret) - ret = -EFAULT; - } + ssize_t ret; - bv_len -= bytes; - bv_addr += bytes; - iov_iter_advance(&iov_iter, bytes); - } + ret = copy_page_from_iter(bvec->bv_page, + bvec->bv_offset, + bvec->bv_len, + &iter); + + if (!iov_iter_count(&iter)) + break; + + if (ret < bvec->bv_len) + return -EFAULT; } - return ret; + return 0; +} + +/** + * bio_copy_to_iter - copy all pages from bio to iov_iter + * @bio: The &struct bio which describes the I/O as source + * @iter: iov_iter as destination + * + * Copy all pages from bio to iov_iter. + * Returns 0 on success, or error on failure. + */ +static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter) +{ + int i; + struct bio_vec *bvec; + + bio_for_each_segment_all(bvec, bio, i) { + ssize_t ret; + + ret = copy_page_to_iter(bvec->bv_page, + bvec->bv_offset, + bvec->bv_len, + &iter); + + if (!iov_iter_count(&iter)) + break; + + if (ret < bvec->bv_len) + return -EFAULT; + } + + return 0; } static void bio_free_pages(struct bio *bio) @@ -1101,9 +1124,8 @@ int bio_uncopy_user(struct bio *bio) * if we're in a workqueue, the request is orphaned, so * don't copy into a random user address space, just free. */ - if (current->mm) - ret = __bio_copy_iov(bio, &bmd->iter, - bio_data_dir(bio) == READ, 0); + if (current->mm && bio_data_dir(bio) == READ) + ret = bio_copy_to_iter(bio, bmd->iter); if (bmd->is_our_pages) bio_free_pages(bio); } @@ -1228,7 +1250,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q, */ if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) || (map_data && map_data->from_user)) { - ret = __bio_copy_iov(bio, iter, 0, 1); + ret = bio_copy_from_iter(bio, *iter); if (ret) goto cleanup; } -- cgit v1.2.3