From d2d30a376d9cc94c6fb730c58b3e5b7426ecb6de Mon Sep 17 00:00:00 2001
From: Sagi Grimberg <sagi@grimberg.me>
Date: Wed, 26 Jun 2024 13:00:08 +0300
Subject: [PATCH] net: allow skb_datagram_iter to be called from any context
We only use the mapping in a single context, so kmap_local is sufficient
and cheaper. Make sure to use skb_frag_foreach_page as skb frags may
contain compound pages and we need to map page by page.
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202406161539.b5ff7b20-oliver.sang@intel.com
Fixes: 950fcaecd5cc ("datagram: consolidate datagram copy to iter helpers")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Link: https://patch.msgid.link/20240626100008.831849-1-sagi@grimberg.me
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
net/core/datagram.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/net/core/datagram.c b/net/core/datagram.c
index e614cfd8e14a5..e9ba4c7b449db 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -416,15 +416,22 @@ static int __skb_datagram_iter(const struct sk_buff *skb, int offset,
end = start + skb_frag_size(frag);
if ((copy = end - offset) > 0) {
- struct page *page = skb_frag_page(frag);
- u8 *vaddr = kmap(page);
+ u32 p_off, p_len, copied;
+ struct page *p;
+ u8 *vaddr;
if (copy > len)
copy = len;
- n = INDIRECT_CALL_1(cb, simple_copy_to_iter,
- vaddr + skb_frag_off(frag) + offset - start,
- copy, data, to);
- kunmap(page);
+
+ skb_frag_foreach_page(frag,
+ skb_frag_off(frag) + offset - start,
+ copy, p, p_off, p_len, copied) {
+ vaddr = kmap_local_page(p);
+ n = INDIRECT_CALL_1(cb, simple_copy_to_iter,
+ vaddr + p_off, p_len, data, to);
+ kunmap_local(vaddr);
+ }
+
offset += n;
if (n != copy)
goto short_copy;
--
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