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@grimberg.me>
Link: https://patch.msgid.link/20240626070153.759257-1-sagi@grimberg.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/datagram.c b/net/core/datagram.c
index 95f2425..e614cfd 100644 (file)
--- 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;