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Subject: [PATCH 03/29] iov_iter: Split iov_iter_fault_in_readable
From:   David Howells <dhowells@redhat.com>
To:     Pavel Begunkov <asml.silence@gmail.com>,
        Matthew Wilcox <willy@infradead.org>,
        Jens Axboe <axboe@kernel.dk>,
        Alexander Viro <viro@zeniv.linux.org.uk>
Cc:     dhowells@redhat.com,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org
Date:   Sat, 21 Nov 2020 14:13:46 +0000
Message-ID: <160596802633.154728.149371155811186006.stgit@warthog.procyon.org.uk>
In-Reply-To: <160596800145.154728.7192318545120181269.stgit@warthog.procyon.org.uk>
References: <160596800145.154728.7192318545120181269.stgit@warthog.procyon.org.uk>
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Split iov_iter_fault_in_readable() by type.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 lib/iov_iter.c |   29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index fee8e99fbb9c..280b5c9c9a9c 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -439,20 +439,23 @@ static size_t pipe_copy_page_to_iter(struct page *page, size_t offset, size_t by
  * Return 0 on success, or non-zero if the memory could not be accessed (i.e.
  * because it is an invalid address).
  */
-static int xxx_fault_in_readable(struct iov_iter *i, size_t bytes)
+static int iovec_fault_in_readable(struct iov_iter *i, size_t bytes)
 {
 	size_t skip = i->iov_offset;
 	const struct iovec *iov;
 	int err;
 	struct iovec v;
 
-	if (!(iov_iter_type(i) & (ITER_BVEC|ITER_KVEC))) {
-		iterate_iovec(i, bytes, v, iov, skip, ({
-			err = fault_in_pages_readable(v.iov_base, v.iov_len);
-			if (unlikely(err))
-			return err;
-		0;}))
-	}
+	iterate_iovec(i, bytes, v, iov, skip, ({
+		err = fault_in_pages_readable(v.iov_base, v.iov_len);
+		if (unlikely(err))
+		return err;
+	0;}))
+	return 0;
+}
+
+static int no_fault_in_readable(struct iov_iter *i, size_t bytes)
+{
 	return 0;
 }
 
@@ -1846,7 +1849,7 @@ static const struct iov_iter_ops iovec_iter_ops = {
 	.copy_from_user_atomic		= xxx_copy_from_user_atomic,
 	.advance			= xxx_advance,
 	.revert				= xxx_revert,
-	.fault_in_readable		= xxx_fault_in_readable,
+	.fault_in_readable		= iovec_fault_in_readable,
 	.single_seg_count		= xxx_single_seg_count,
 	.copy_page_to_iter		= iovec_copy_page_to_iter,
 	.copy_page_from_iter		= xxx_copy_page_from_iter,
@@ -1880,7 +1883,7 @@ static const struct iov_iter_ops kvec_iter_ops = {
 	.copy_from_user_atomic		= xxx_copy_from_user_atomic,
 	.advance			= xxx_advance,
 	.revert				= xxx_revert,
-	.fault_in_readable		= xxx_fault_in_readable,
+	.fault_in_readable		= no_fault_in_readable,
 	.single_seg_count		= xxx_single_seg_count,
 	.copy_page_to_iter		= bkvec_copy_page_to_iter,
 	.copy_page_from_iter		= xxx_copy_page_from_iter,
@@ -1914,7 +1917,7 @@ static const struct iov_iter_ops bvec_iter_ops = {
 	.copy_from_user_atomic		= xxx_copy_from_user_atomic,
 	.advance			= xxx_advance,
 	.revert				= xxx_revert,
-	.fault_in_readable		= xxx_fault_in_readable,
+	.fault_in_readable		= no_fault_in_readable,
 	.single_seg_count		= xxx_single_seg_count,
 	.copy_page_to_iter		= bkvec_copy_page_to_iter,
 	.copy_page_from_iter		= xxx_copy_page_from_iter,
@@ -1948,7 +1951,7 @@ static const struct iov_iter_ops pipe_iter_ops = {
 	.copy_from_user_atomic		= xxx_copy_from_user_atomic,
 	.advance			= xxx_advance,
 	.revert				= xxx_revert,
-	.fault_in_readable		= xxx_fault_in_readable,
+	.fault_in_readable		= no_fault_in_readable,
 	.single_seg_count		= xxx_single_seg_count,
 	.copy_page_to_iter		= pipe_copy_page_to_iter,
 	.copy_page_from_iter		= xxx_copy_page_from_iter,
@@ -1982,7 +1985,7 @@ static const struct iov_iter_ops discard_iter_ops = {
 	.copy_from_user_atomic		= xxx_copy_from_user_atomic,
 	.advance			= xxx_advance,
 	.revert				= xxx_revert,
-	.fault_in_readable		= xxx_fault_in_readable,
+	.fault_in_readable		= no_fault_in_readable,
 	.single_seg_count		= xxx_single_seg_count,
 	.copy_page_to_iter		= discard_copy_page_to_iter,
 	.copy_page_from_iter		= xxx_copy_page_from_iter,