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 <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dongsu Park <dongsu.park@profitbricks.com>
[hch: removed the __bio_copy_iov wrapper]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/bio.c b/block/bio.c
index 0723d4c..f66a4ea 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1036,43 +1036,66 @@
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;
+ ssize_t ret;
- 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);
+ ret = copy_page_from_iter(bvec->bv_page,
+ bvec->bv_offset,
+ bvec->bv_len,
+ &iter);
- if (!ret) {
- if (to_user)
- ret = copy_to_user(iov.iov_base,
- bv_addr, bytes);
+ if (!iov_iter_count(&iter))
+ break;
- if (from_user)
- ret = copy_from_user(bv_addr,
- iov.iov_base,
- bytes);
-
- if (ret)
- ret = -EFAULT;
- }
-
- bv_len -= bytes;
- bv_addr += bytes;
- iov_iter_advance(&iov_iter, bytes);
- }
+ 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 @@
* 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 @@
*/
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;
}