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| author | Willem de Bruijn <willemb@google.com> | 2021-01-10 01:18:34 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-01-12 05:20:09 +0300 |
| commit | 9bd6b629c39e3fa9e14243a6d8820492be1a5b2e (patch) | |
| tree | a5a886f486cb705d9e421bf20b742950b7cf8191 /net/ipv6 | |
| parent | 97550f6fa59254435d864b92603de3ca4b5a99f8 (diff) | |
| download | linux-9bd6b629c39e3fa9e14243a6d8820492be1a5b2e.tar.xz | |
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/ipv6')
| -rw-r--r-- | net/ipv6/esp6.c | 7 |
1 files changed, 1 insertions, 6 deletions
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, |