On 2024/7/2 23:52, Alexander H Duyck wrote:

On Tue, 2024-06-25 at 21:52 +0800, Yunsheng Lin wrote:

quoted

introduce the skb_copy_to_va_nocache() helper to avoid
calling virt_to_page() and skb_copy_to_page_nocache().

CC: Alexander Duyck <redacted>
Signed-off-by: Yunsheng Lin <redacted>
---
 include/net/sock.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/include/net/sock.h b/include/net/sock.h
index cce23ac4d514..7ad235465485 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h

@@ -2201,6 +2201,21 @@ static inline int skb_copy_to_page_nocache(struct sock *sk, struct iov_iter *fro
 	return 0;
 }
 
+static inline int skb_copy_to_va_nocache(struct sock *sk, struct iov_iter *from,
+					 struct sk_buff *skb, char *va, int copy)
+{
+	int err;
+
+	err = skb_do_copy_data_nocache(sk, skb, from, va, copy, skb->len);
+	if (err)
+		return err;
+
+	skb_len_add(skb, copy);
+	sk_wmem_queued_add(sk, copy);
+	sk_mem_charge(sk, copy);
+	return 0;
+}
+
 /**
  * sk_wmem_alloc_get - returns write allocations
  * @sk: socket

One minor nit. Rather than duplicate skb_copy_to_page_nocache you would
be better served to implement this one before it, and then just update
skb_copy_to_page_nocache to be:
	return skb_copy_to_va_nocache(sk, from, skb,
				      page_address(page) + off, copy);

We can save ourselves at least a few lines of code that way and it
creates one spot to do any changes.

Looking at more closely, it seems we may be able to just rename
skb_copy_to_page_nocache() to skb_copy_to_va_nocache() as there
is no caller for skb_copy_to_page_nocache() after this patchset.

				
.