Re: [PATCH v5 07/11] iov_iter: Add a kernel-type iterator-only iteration function
From: Simon Horman <horms@kernel.org>
Date: 2023-09-22 09:34:21
Also in:
linux-block, linux-fsdevel, linux-mm, lkml
On Wed, Sep 20, 2023 at 11:22:27PM +0100, David Howells wrote:
quoted hunk ↗ jump to hunk
Add an iteration function that can only iterate over kernel internal-type iterators (ie. BVEC, KVEC, XARRAY) and not user-backed iterators (ie. UBUF and IOVEC). This allows for smaller iterators to be built when it is known the caller won't have a user-backed iterator. Signed-off-by: David Howells <dhowells@redhat.com> cc: Alexander Viro <viro@zeniv.linux.org.uk> cc: Jens Axboe <axboe@kernel.dk> cc: Christoph Hellwig <hch@lst.de> cc: Christian Brauner <christian@brauner.io> cc: Matthew Wilcox <willy@infradead.org> cc: Linus Torvalds <torvalds@linux-foundation.org> cc: David Laight <redacted> cc: linux-block@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- include/linux/iov_iter.h | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+)diff --git a/include/linux/iov_iter.h b/include/linux/iov_iter.h index 270454a6703d..a94d605d7386 100644 --- a/include/linux/iov_iter.h +++ b/include/linux/iov_iter.h@@ -271,4 +271,35 @@ size_t iterate_and_advance(struct iov_iter *iter, size_t len, void *priv, return iterate_and_advance2(iter, len, priv, NULL, ustep, step); } +/** + * iterate_and_advance_kernel - Iterate over a kernel iterator + * @iter: The iterator to iterate over. + * @len: The amount to iterate over. + * @priv: Data for the step functions.
nit: an entry for @priv2 belongs here
+ * @step: Processing function; given kernel addresses.
+ *
+ * Like iterate_and_advance2(), but rejected UBUF and IOVEC iterators and does
+ * not take a user-step function.
+ */
+static __always_inline
+size_t iterate_and_advance_kernel(struct iov_iter *iter, size_t len, void *priv,
+ void *priv2, iov_step_f step)
+{...