Rewrite __bio_copy_iov() so that it can call either _read() or _write() variant, which is determined by direction to_iov, given as either READ or WRITE. Moreover, make __bio_copy_iov() take its parameter iov_iter by value, to avoid awkward situations like ref-/dereferencing pointer and value repeatedly.
This commit should contain only literal replacements, without functional changes. Suggested-by: Christoph Hellwig <[email protected]> Cc: Kent Overstreet <[email protected]> Cc: Jens Axboe <[email protected]> Cc: Al Viro <[email protected]> Signed-off-by: Dongsu Park <[email protected]> --- block/bio.c | 113 ++++++++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 75 insertions(+), 38 deletions(-) diff --git a/block/bio.c b/block/bio.c index 8267676..7b1aed3 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1046,46 +1046,84 @@ static struct bio_map_data *bio_alloc_map_data(unsigned int iov_count, sizeof(struct sg_iovec) * iov_count, gfp_mask); } -static int __bio_copy_iov(struct bio *bio, const struct iov_iter *iter, - int to_user, int from_user, int do_free_page) +/** + * __bio_copy_iov_read - 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_iov_read(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 (do_free_page) - __free_page(bvec->bv_page); + if (!iov_iter_count(&iter)) + break; + + if (ret < bvec->bv_len) + return -EFAULT; } - return ret; + return 0; +} + +/** + * __bio_copy_iov_write - 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_iov_write(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; +} + +/** + * __bio_copy_iov - copy all pages between bio and iov_iter + * @bio: The &struct bio which describes the I/O + * @iter: iov_iter either as source or destination + * @to_iov: whether to %READ (0) or %WRITE (1) + * + * Simple wrapper around __bio_copy_iov_{write,read}(). + * Returns 0 on success, or the error returned as-is on failure. + */ +static inline int __bio_copy_iov(struct bio *bio, struct iov_iter iter, + int to_iov) +{ + if (to_iov == WRITE) + return __bio_copy_iov_write(bio, iter); + else + return __bio_copy_iov_read(bio, iter); } /** @@ -1106,11 +1144,10 @@ 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, bmd->is_our_pages); - else if (bmd->is_our_pages) + if (current->mm && bio_data_dir(bio) == READ) + ret = __bio_copy_iov(bio, bmd->iter, WRITE); + + if (bmd->is_our_pages) bio_for_each_segment_all(bvec, bio, i) __free_page(bvec->bv_page); } @@ -1233,7 +1270,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q, */ if ((!write_to_vm && (!map_data || !map_data->null_mapped)) || (map_data && map_data->from_user)) { - ret = __bio_copy_iov(bio, iter, 0, 1, 0); + ret = __bio_copy_iov(bio, *iter, READ); if (ret) goto cleanup; } -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
