netdev - [PATCH] Revert "net: micro-optimize skb_datagram

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Date: Wed, 26 Jun 2024 10:00:37 +0300
From: Sagi Grimberg <sagi@...mberg.me>
To: netdev@...r.kernel.org,
	Jakub Kicinski <kuba@...nel.org>
Cc: Eric Dumazet <edumazet@...gle.com>,
	David Howells <dhowells@...hat.com>,
	Matthew Wilcox <willy@...radead.org>
Subject: [PATCH] Revert "net: micro-optimize skb_datagram_iter"

This reverts commit 934c29999b57b835d65442da6f741d5e27f3b584.
This triggered a usercopy BUG() in systems with HIGHMEM, reported
by the test robot in:
 https://lore.kernel.org/oe-lkp/202406161539.b5ff7b20-oliver.sang@intel.com

Signed-off-by: Sagi Grimberg <sagi@...mberg.me>
---
 net/core/datagram.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/datagram.c b/net/core/datagram.c
index 95f242591fd2..e614cfd8e14a 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -417,14 +417,14 @@ 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_local_page(page);
+			u8 *vaddr = kmap(page);
 
 			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_local(vaddr);
+			kunmap(page);
 			offset += n;
 			if (n != copy)
 				goto short_copy;
-- 
2.43.0