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From:   David Howells <dhowells@redhat.com>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     David Howells <dhowells@redhat.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Christoph Hellwig <hch@lst.de>,
        Christian Brauner <christian@brauner.io>,
        David Laight <David.Laight@ACULAB.COM>,
        Matthew Wilcox <willy@infradead.org>,
        Jeff Layton <jlayton@kernel.org>,
        linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
        linux-mm@kvack.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Subject: [PATCH v7 09/12] iov_iter, net: Move csum_and_copy_to/from_iter() to net/
Date:   Mon, 25 Sep 2023 13:03:06 +0100
Message-ID: <20230925120309.1731676-10-dhowells@redhat.com>
In-Reply-To: <20230925120309.1731676-1-dhowells@redhat.com>
References: <20230925120309.1731676-1-dhowells@redhat.com>
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Move csum_and_copy_to/from_iter() to net code now that the iteration
framework can be #included.

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 <David.Laight@ACULAB.COM>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
cc: netdev@vger.kernel.org
---
 include/linux/skbuff.h | 25 ++++++++++++
 include/linux/uio.h    | 18 ---------
 lib/iov_iter.c         | 89 ------------------------------------------
 net/core/datagram.c    | 50 +++++++++++++++++++++++-
 net/core/skbuff.c      | 33 ++++++++++++++++
 5 files changed, 107 insertions(+), 108 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 4174c4b82d13..d0656cc11c16 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3679,6 +3679,31 @@ static inline int __must_check skb_put_padto(struct sk_buff *skb, unsigned int l
 	return __skb_put_padto(skb, len, true);
 }
 
+static inline __wsum csum_and_memcpy(void *to, const void *from, size_t len,
+				     __wsum sum, size_t off)
+{
+	__wsum next = csum_partial_copy_nocheck(from, to, len);
+	return csum_block_add(sum, next, off);
+}
+
+struct csum_state {
+	__wsum csum;
+	size_t off;
+};
+
+size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
+
+static __always_inline __must_check
+bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
+				  __wsum *csum, struct iov_iter *i)
+{
+	size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i);
+	if (likely(copied == bytes))
+		return true;
+	iov_iter_revert(i, copied);
+	return false;
+}
+
 static inline int skb_add_data(struct sk_buff *skb,
 			       struct iov_iter *from, int copy)
 {
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 65d9143f83c8..0a5426c97e02 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -338,24 +338,6 @@ iov_iter_npages_cap(struct iov_iter *i, int maxpages, size_t max_bytes)
 	return npages;
 }
 
-struct csum_state {
-	__wsum csum;
-	size_t off;
-};
-
-size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i);
-size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
-
-static __always_inline __must_check
-bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
-				  __wsum *csum, struct iov_iter *i)
-{
-	size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i);
-	if (likely(copied == bytes))
-		return true;
-	iov_iter_revert(i, copied);
-	return false;
-}
 size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
 		struct iov_iter *i);
 
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 943aa3cfd7b3..fef934a8745d 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -10,7 +10,6 @@
 #include <linux/vmalloc.h>
 #include <linux/splice.h>
 #include <linux/compat.h>
-#include <net/checksum.h>
 #include <linux/scatterlist.h>
 #include <linux/instrumented.h>
 #include <linux/iov_iter.h>
@@ -179,13 +178,6 @@ void iov_iter_init(struct iov_iter *i, unsigned int direction,
 }
 EXPORT_SYMBOL(iov_iter_init);
 
-static __wsum csum_and_memcpy(void *to, const void *from, size_t len,
-			      __wsum sum, size_t off)
-{
-	__wsum next = csum_partial_copy_nocheck(from, to, len);
-	return csum_block_add(sum, next, off);
-}
-
 size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
 {
 	if (WARN_ON_ONCE(i->data_source))
@@ -1101,87 +1093,6 @@ ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i,
 }
 EXPORT_SYMBOL(iov_iter_get_pages_alloc2);
 
-static __always_inline
-size_t copy_from_user_iter_csum(void __user *iter_from, size_t progress,
-				size_t len, void *to, void *priv2)
-{
-	__wsum next, *csum = priv2;
-
-	next = csum_and_copy_from_user(iter_from, to + progress, len);
-	*csum = csum_block_add(*csum, next, progress);
-	return next ? 0 : len;
-}
-
-static __always_inline
-size_t memcpy_from_iter_csum(void *iter_from, size_t progress,
-			     size_t len, void *to, void *priv2)
-{
-	__wsum *csum = priv2;
-
-	*csum = csum_and_memcpy(to + progress, iter_from, len, *csum, progress);
-	return 0;
-}
-
-size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
-			       struct iov_iter *i)
-{
-	if (WARN_ON_ONCE(!i->data_source))
-		return 0;
-	return iterate_and_advance2(i, bytes, addr, csum,
-				    copy_from_user_iter_csum,
-				    memcpy_from_iter_csum);
-}
-EXPORT_SYMBOL(csum_and_copy_from_iter);
-
-static __always_inline
-size_t copy_to_user_iter_csum(void __user *iter_to, size_t progress,
-			      size_t len, void *from, void *priv2)
-{
-	__wsum next, *csum = priv2;
-
-	next = csum_and_copy_to_user(from + progress, iter_to, len);
-	*csum = csum_block_add(*csum, next, progress);
-	return next ? 0 : len;
-}
-
-static __always_inline
-size_t memcpy_to_iter_csum(void *iter_to, size_t progress,
-			   size_t len, void *from, void *priv2)
-{
-	__wsum *csum = priv2;
-
-	*csum = csum_and_memcpy(iter_to, from + progress, len, *csum, progress);
-	return 0;
-}
-
-size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate,
-			     struct iov_iter *i)
-{
-	struct csum_state *csstate = _csstate;
-	__wsum sum;
-
-	if (WARN_ON_ONCE(i->data_source))
-		return 0;
-	if (unlikely(iov_iter_is_discard(i))) {
-		// can't use csum_memcpy() for that one - data is not copied
-		csstate->csum = csum_block_add(csstate->csum,
-					       csum_partial(addr, bytes, 0),
-					       csstate->off);
-		csstate->off += bytes;
-		return bytes;
-	}
-
-	sum = csum_shift(csstate->csum, csstate->off);
-	
-	bytes = iterate_and_advance2(i, bytes, (void *)addr, &sum,
-				     copy_to_user_iter_csum,
-				     memcpy_to_iter_csum);
-	csstate->csum = csum_shift(sum, csstate->off);
-	csstate->off += bytes;
-	return bytes;
-}
-EXPORT_SYMBOL(csum_and_copy_to_iter);
-
 size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
 		struct iov_iter *i)
 {
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 176eb5834746..37c89d0933b7 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -50,7 +50,7 @@
 #include <linux/spinlock.h>
 #include <linux/slab.h>
 #include <linux/pagemap.h>
-#include <linux/uio.h>
+#include <linux/iov_iter.h>
 #include <linux/indirect_call_wrapper.h>
 
 #include <net/protocol.h>
@@ -716,6 +716,54 @@ int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *from)
 }
 EXPORT_SYMBOL(zerocopy_sg_from_iter);
 
+static __always_inline
+size_t copy_to_user_iter_csum(void __user *iter_to, size_t progress,
+			      size_t len, void *from, void *priv2)
+{
+	__wsum next, *csum = priv2;
+
+	next = csum_and_copy_to_user(from + progress, iter_to, len);
+	*csum = csum_block_add(*csum, next, progress);
+	return next ? 0 : len;
+}
+
+static __always_inline
+size_t memcpy_to_iter_csum(void *iter_to, size_t progress,
+			   size_t len, void *from, void *priv2)
+{
+	__wsum *csum = priv2;
+
+	*csum = csum_and_memcpy(iter_to, from + progress, len, *csum, progress);
+	return 0;
+}
+
+static size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate,
+				    struct iov_iter *i)
+{
+	struct csum_state *csstate = _csstate;
+	__wsum sum;
+
+	if (WARN_ON_ONCE(i->data_source))
+		return 0;
+	if (unlikely(iov_iter_is_discard(i))) {
+		// can't use csum_memcpy() for that one - data is not copied
+		csstate->csum = csum_block_add(csstate->csum,
+					       csum_partial(addr, bytes, 0),
+					       csstate->off);
+		csstate->off += bytes;
+		return bytes;
+	}
+
+	sum = csum_shift(csstate->csum, csstate->off);
+
+	bytes = iterate_and_advance2(i, bytes, (void *)addr, &sum,
+				     copy_to_user_iter_csum,
+				     memcpy_to_iter_csum);
+	csstate->csum = csum_shift(sum, csstate->off);
+	csstate->off += bytes;
+	return bytes;
+}
+
 /**
  *	skb_copy_and_csum_datagram - Copy datagram to an iovec iterator
  *          and update a checksum.
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 4eaf7ed0d1f4..5dbdfce2d05f 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -62,6 +62,7 @@
 #include <linux/if_vlan.h>
 #include <linux/mpls.h>
 #include <linux/kcov.h>
+#include <linux/iov_iter.h>
 
 #include <net/protocol.h>
 #include <net/dst.h>
@@ -6931,3 +6932,35 @@ ssize_t skb_splice_from_iter(struct sk_buff *skb, struct iov_iter *iter,
 	return spliced ?: ret;
 }
 EXPORT_SYMBOL(skb_splice_from_iter);
+
+static __always_inline
+size_t memcpy_from_iter_csum(void *iter_from, size_t progress,
+			     size_t len, void *to, void *priv2)
+{
+	__wsum *csum = priv2;
+
+	*csum = csum_and_memcpy(to + progress, iter_from, len, *csum, progress);
+	return 0;
+}
+
+static __always_inline
+size_t copy_from_user_iter_csum(void __user *iter_from, size_t progress,
+				size_t len, void *to, void *priv2)
+{
+	__wsum next, *csum = priv2;
+
+	next = csum_and_copy_from_user(iter_from, to + progress, len);
+	*csum = csum_block_add(*csum, next, progress);
+	return next ? 0 : len;
+}
+
+size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
+			       struct iov_iter *i)
+{
+	if (WARN_ON_ONCE(!i->data_source))
+		return 0;
+	return iterate_and_advance2(i, bytes, addr, csum,
+				    copy_from_user_iter_csum,
+				    memcpy_from_iter_csum);
+}
+EXPORT_SYMBOL(csum_and_copy_from_iter);