linux-kernel - [PATCH net-next 07/12] net: Clean up users of netdev_alloc_cache and napi_frag

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Message-Id: <20230524153311.3625329-8-dhowells@redhat.com>
Date:   Wed, 24 May 2023 16:33:06 +0100
From:   David Howells <dhowells@...hat.com>
To:     netdev@...r.kernel.org
Cc:     David Howells <dhowells@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Willem de Bruijn <willemdebruijn.kernel@...il.com>,
        David Ahern <dsahern@...nel.org>,
        Matthew Wilcox <willy@...radead.org>,
        Jens Axboe <axboe@...nel.dk>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH net-next 07/12] net: Clean up users of netdev_alloc_cache and napi_frag_cache

The users of netdev_alloc_cache and napi_frag_cache don't need to take the
bh lock around access to these fragment caches any more as the percpu
handling is now done in page_frag_alloc_align().

Signed-off-by: David Howells <dhowells@...hat.com>
cc: "David S. Miller" <davem@...emloft.net>
cc: Eric Dumazet <edumazet@...gle.com>
cc: Jakub Kicinski <kuba@...nel.org>
cc: Paolo Abeni <pabeni@...hat.com>
cc: linux-mm@...ck.org
---
 include/linux/skbuff.h |  3 ++-
 net/core/skbuff.c      | 29 +++++++++--------------------
 2 files changed, 11 insertions(+), 21 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 41b63e72c6c3..e11a765fe7fa 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -252,7 +252,8 @@
 /* Maximum value in skb->csum_level */
 #define SKB_MAX_CSUM_LEVEL	3
 
-#define SKB_DATA_ALIGN(X)	ALIGN(X, SMP_CACHE_BYTES)
+#define SKB_DATA_ALIGNMENT	SMP_CACHE_BYTES
+#define SKB_DATA_ALIGN(X)	ALIGN(X, SKB_DATA_ALIGNMENT)
 #define SKB_WITH_OVERHEAD(X)	\
 	((X) - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
 
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 225a16f3713f..c2840b0dcad9 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -291,27 +291,20 @@ void napi_get_frags_check(struct napi_struct *napi)
 
 void *napi_alloc_frag_align(unsigned int fragsz, unsigned int align)
 {
-	fragsz = SKB_DATA_ALIGN(fragsz);
-
+	align = min_t(unsigned int, align, SKB_DATA_ALIGNMENT);
 	return page_frag_alloc_align(&napi_frag_cache, fragsz, GFP_ATOMIC, align);
 }
 EXPORT_SYMBOL(napi_alloc_frag_align);
 
 void *netdev_alloc_frag_align(unsigned int fragsz, unsigned int align)
 {
-	void *data;
-
-	fragsz = SKB_DATA_ALIGN(fragsz);
-	if (in_hardirq() || irqs_disabled()) {
-		data = page_frag_alloc_align(&netdev_alloc_cache,
+	align = min_t(unsigned int, align, SKB_DATA_ALIGNMENT);
+	if (in_hardirq() || irqs_disabled())
+		return page_frag_alloc_align(&netdev_alloc_cache,
 					     fragsz, GFP_ATOMIC, align);
-	} else {
-		local_bh_disable();
-		data = page_frag_alloc_align(&napi_frag_cache,
+	else
+		return page_frag_alloc_align(&napi_frag_cache,
 					     fragsz, GFP_ATOMIC, align);
-		local_bh_enable();
-	}
-	return data;
 }
 EXPORT_SYMBOL(netdev_alloc_frag_align);
 
@@ -709,15 +702,11 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len,
 	if (sk_memalloc_socks())
 		gfp_mask |= __GFP_MEMALLOC;
 
-	if (in_hardirq() || irqs_disabled()) {
+	if (in_hardirq() || irqs_disabled())
 		data = page_frag_alloc(&netdev_alloc_cache, len, gfp_mask);
-		pfmemalloc = folio_is_pfmemalloc(virt_to_folio(data));
-	} else {
-		local_bh_disable();
+	else
 		data = page_frag_alloc(&napi_frag_cache, len, gfp_mask);
-		pfmemalloc = folio_is_pfmemalloc(virt_to_folio(data));
-		local_bh_enable();
-	}
+	pfmemalloc = folio_is_pfmemalloc(virt_to_folio(data));
 
 	if (unlikely(!data))
 		return NULL;