[PATCH net-next] net: skbuff: update commemt about pfmemalloc propagating

From: Yunsheng Lin
Date: Mon May 15 2023 - 00:56:57 EST


__skb_fill_page_desc_noacc() is not doing any pfmemalloc
propagating, and yet it has a comment about that, commit
84ce071e38a6 ("net: introduce __skb_fill_page_desc_noacc")
may have accidentally move to __skb_fill_page_desc_noacc(),
so move it back to __skb_fill_page_desc() which is supposed
to be doing pfmemalloc propagating.

Signed-off-by: Yunsheng Lin <linyunsheng@xxxxxxxxxx>
CC: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
Also maybe we need a better name for 'noacc' or add some
comment about that, as 'noacc' seems a little confusing
for __skb_fill_page_desc_noacc().
---
include/linux/skbuff.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 00e8c435fa1a..4b8d55247198 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2426,11 +2426,6 @@ static inline void __skb_fill_page_desc_noacc(struct skb_shared_info *shinfo,
{
skb_frag_t *frag = &shinfo->frags[i];

- /*
- * Propagate page pfmemalloc to the skb if we can. The problem is
- * that not all callers have unique ownership of the page but rely
- * on page_is_pfmemalloc doing the right thing(tm).
- */
skb_frag_fill_page_desc(frag, page, off, size);
}

@@ -2463,6 +2458,11 @@ static inline void __skb_fill_page_desc(struct sk_buff *skb, int i,
struct page *page, int off, int size)
{
__skb_fill_page_desc_noacc(skb_shinfo(skb), i, page, off, size);
+
+ /* Propagate page pfmemalloc to the skb if we can. The problem is
+ * that not all callers have unique ownership of the page but rely
+ * on page_is_pfmemalloc doing the right thing(tm).
+ */
page = compound_head(page);
if (page_is_pfmemalloc(page))
skb->pfmemalloc = true;
--
2.33.0