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authorDavid Howells <dhowells@redhat.com>2023-05-31 12:04:21 +0100
committerJakub Kicinski <kuba@kernel.org>2023-06-05 20:51:56 -0700
commit2b03bcae66c7b29f151e51d3109dbe1e31272235 (patch)
tree4d689af06ac3c23747c1eab54d3e875b65216fad /net
parent28cfea989d6f55c3d10608eba2a2bae609c5bf3e (diff)
kcm: Support MSG_SPLICE_PAGES
Make AF_KCM sendmsg() support MSG_SPLICE_PAGES. This causes pages to be spliced from the source iterator if possible. This allows ->sendpage() to be replaced by something that can handle multiple multipage folios in a single transaction. Signed-off-by: David Howells <dhowells@redhat.com> cc: Tom Herbert <tom@herbertland.com> cc: Tom Herbert <tom@quantonium.net> cc: Cong Wang <cong.wang@bytedance.com> cc: Jens Axboe <axboe@kernel.dk> cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/kcm/kcmsock.c57
1 files changed, 40 insertions, 17 deletions
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index cfe828bd7fc6..8555ede66333 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -989,29 +989,52 @@ start:
merge = false;
}
- copy = min_t(int, msg_data_left(msg),
- pfrag->size - pfrag->offset);
+ if (msg->msg_flags & MSG_SPLICE_PAGES) {
+ copy = msg_data_left(msg);
+ if (!sk_wmem_schedule(sk, copy))
+ goto wait_for_memory;
- if (!sk_wmem_schedule(sk, copy))
- goto wait_for_memory;
+ err = skb_splice_from_iter(skb, &msg->msg_iter, copy,
+ sk->sk_allocation);
+ if (err < 0) {
+ if (err == -EMSGSIZE)
+ goto wait_for_memory;
+ goto out_error;
+ }
- err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
- pfrag->page,
- pfrag->offset,
- copy);
- if (err)
- goto out_error;
+ copy = err;
+ skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG;
+ sk_wmem_queued_add(sk, copy);
+ sk_mem_charge(sk, copy);
- /* Update the skb. */
- if (merge) {
- skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
+ if (head != skb)
+ head->truesize += copy;
} else {
- skb_fill_page_desc(skb, i, pfrag->page,
- pfrag->offset, copy);
- get_page(pfrag->page);
+ copy = min_t(int, msg_data_left(msg),
+ pfrag->size - pfrag->offset);
+ if (!sk_wmem_schedule(sk, copy))
+ goto wait_for_memory;
+
+ err = skb_copy_to_page_nocache(sk, &msg->msg_iter, skb,
+ pfrag->page,
+ pfrag->offset,
+ copy);
+ if (err)
+ goto out_error;
+
+ /* Update the skb. */
+ if (merge) {
+ skb_frag_size_add(
+ &skb_shinfo(skb)->frags[i - 1], copy);
+ } else {
+ skb_fill_page_desc(skb, i, pfrag->page,
+ pfrag->offset, copy);
+ get_page(pfrag->page);
+ }
+
+ pfrag->offset += copy;
}
- pfrag->offset += copy;
copied += copy;
if (head != skb) {
head->len += copy;