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authorWillem de Bruijn <willemb@google.com>2021-01-09 17:18:34 -0500
committerJakub Kicinski <kuba@kernel.org>2021-01-11 18:20:09 -0800
commit9bd6b629c39e3fa9e14243a6d8820492be1a5b2e (patch)
treea5a886f486cb705d9e421bf20b742950b7cf8191 /net
parent97550f6fa59254435d864b92603de3ca4b5a99f8 (diff)
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esp: avoid unneeded kmap_atomic call
esp(6)_output_head uses skb_page_frag_refill to allocate a buffer for the esp trailer. It accesses the page with kmap_atomic to handle highmem. But skb_page_frag_refill can return compound pages, of which kmap_atomic only maps the first underlying page. skb_page_frag_refill does not return highmem, because flag __GFP_HIGHMEM is not set. ESP uses it in the same manner as TCP. That also does not call kmap_atomic, but directly uses page_address, in skb_copy_to_page_nocache. Do the same for ESP. This issue has become easier to trigger with recent kmap local debugging feature CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP. Fixes: cac2661c53f3 ("esp4: Avoid skb_cow_data whenever possible") Fixes: 03e2a30f6a27 ("esp6: Avoid skb_cow_data whenever possible") Signed-off-by: Willem de Bruijn <willemb@google.com> Acked-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/esp4.c7
-rw-r--r--net/ipv6/esp6.c7
2 files changed, 2 insertions, 12 deletions
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 8b07f3a4f2db..a3271ec3e162 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -443,7 +443,6 @@ static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
{
u8 *tail;
- u8 *vaddr;
int nfrags;
int esph_offset;
struct page *page;
@@ -485,14 +484,10 @@ int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *
page = pfrag->page;
get_page(page);
- vaddr = kmap_atomic(page);
-
- tail = vaddr + pfrag->offset;
+ tail = page_address(page) + pfrag->offset;
esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
- kunmap_atomic(vaddr);
-
nfrags = skb_shinfo(skb)->nr_frags;
__skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 52c2f063529f..2b804fcebcc6 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -478,7 +478,6 @@ static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb,
int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
{
u8 *tail;
- u8 *vaddr;
int nfrags;
int esph_offset;
struct page *page;
@@ -519,14 +518,10 @@ int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info
page = pfrag->page;
get_page(page);
- vaddr = kmap_atomic(page);
-
- tail = vaddr + pfrag->offset;
+ tail = page_address(page) + pfrag->offset;
esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
- kunmap_atomic(vaddr);
-
nfrags = skb_shinfo(skb)->nr_frags;
__skb_fill_page_desc(skb, nfrags, page, pfrag->offset,