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[hotfix,6.11,v2,2/3] minmax: reduce min/max macro expansion in skbuff

Message ID a32131084038312529243bc22b06f0ee64c95fb6.1726074904.git.lorenzo.stoakes@oracle.com (mailing list archive)
State New
Headers show
Series minmax: reduce egregious min/max macro expansion | expand

Commit Message

Lorenzo Stoakes Sept. 11, 2024, 5:51 p.m. UTC 
Avoid unnecessary nested min()/max() which reults in egregious macro
expansion.

The nesting occurs when NET_SKB_PAD is used in a min() or max() invocation,
for instance, various ethernet drivers wrap it in a max().

Not doing so results in an impact on build times.

Cc: stable@vger.kernel.org
Fixes: 867046cc7027 ("minmax: relax check to allow comparison between unsigned arguments and signed constants")
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
 include/linux/skbuff.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--
2.46.0
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Patch

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 29c3ea5b6e93..d53b296df504 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3164,7 +3164,11 @@  static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
  * NET_IP_ALIGN(2) + ethernet_header(14) + IP_header(20/40) + ports(8)
  */
 #ifndef NET_SKB_PAD
-#define NET_SKB_PAD	max(32, L1_CACHE_BYTES)
+#if L1_CACHE_BYTES < 32
+#define NET_SKB_PAD	32
+#else
+#define NET_SKB_PAD	L1_CACHE_BYTES
+#endif
 #endif

 int ___pskb_trim(struct sk_buff *skb, unsigned int len);