[PATCH] net: Relax the npages test against MAX_SKB_FRAGS

From: Miaohe Lin
Date: Tue Aug 18 2020 - 07:58:37 EST


The npages test against MAX_SKB_FRAGS can be relaxed if we succeed to
allocate high order pages as the note in comment said.

Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
net/core/skbuff.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 2f7dd689bccc..ca432bbfd90b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5758,13 +5758,6 @@ struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
struct page *page;
int i;

- *errcode = -EMSGSIZE;
- /* Note this test could be relaxed, if we succeed to allocate
- * high order pages...
- */
- if (npages > MAX_SKB_FRAGS)
- return NULL;
-
*errcode = -ENOBUFS;
skb = alloc_skb(header_len, gfp_mask);
if (!skb)
@@ -5775,6 +5768,10 @@ struct sk_buff *alloc_skb_with_frags(unsigned long header_len,
for (i = 0; npages > 0; i++) {
int order = max_page_order;

+ if (unlikely(i >= MAX_SKB_FRAGS)) {
+ *errcode = -EMSGSIZE;
+ goto failure;
+ }
while (order) {
if (npages >= 1 << order) {
page = alloc_pages((gfp_mask & ~__GFP_DIRECT_RECLAIM) |
--
2.19.1