Thread (13 messages) 13 messages, 2 authors, 2024-08-23
STALE656d REVIEWED: 5 (5M)
Revisions (11)
  1. v10 [diff vs current]
  2. v12 [diff vs current]
  3. v13 [diff vs current]
  4. v14 current
  5. v15 [diff vs current]
  6. v16 [diff vs current]
  7. v17 [diff vs current]
  8. v18 [diff vs current]
  9. v20 [diff vs current]
  10. v21 [diff vs current]
  11. v22 [diff vs current]

[PATCH net-next v14 04/11] mm: page_frag: avoid caller accessing 'page_frag_cache' directly

From: Yunsheng Lin <hidden>
Date: 2024-08-23 15:06:47
Also in: kvm, linux-kselftest, linux-mm, linux-nfs, lkml, virtualization
Subsystem: kernel nfsd, sunrpc, and lockd servers, kernel selftest framework, memory management - misc, networking [general], nfs, sunrpc, and lockd clients, rxrpc sockets (af_rxrpc), the rest, virtio host (vhost) · Maintainers: Chuck Lever, Jeff Layton, Shuah Khan, Andrew Morton, David Hildenbrand, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Trond Myklebust, Anna Schumaker, David Howells, Marc Dionne, Linus Torvalds, "Michael S. Tsirkin", Jason Wang

Use appropriate frag_page API instead of caller accessing
'page_frag_cache' directly.

CC: Alexander Duyck <redacted>
Signed-off-by: Yunsheng Lin <redacted>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
---
 drivers/vhost/net.c                                   |  2 +-
 include/linux/page_frag_cache.h                       | 10 ++++++++++
 net/core/skbuff.c                                     |  6 +++---
 net/rxrpc/conn_object.c                               |  4 +---
 net/rxrpc/local_object.c                              |  4 +---
 net/sunrpc/svcsock.c                                  |  6 ++----
 tools/testing/selftests/mm/page_frag/page_frag_test.c |  2 +-
 7 files changed, 19 insertions(+), 15 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index f16279351db5..9ad37c012189 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1325,7 +1325,7 @@ static int vhost_net_open(struct inode *inode, struct file *f)
 			vqs[VHOST_NET_VQ_RX]);
 
 	f->private_data = n;
-	n->pf_cache.va = NULL;
+	page_frag_cache_init(&n->pf_cache);
 
 	return 0;
 }
diff --git a/include/linux/page_frag_cache.h b/include/linux/page_frag_cache.h
index 67ac8626ed9b..0a52f7a179c8 100644
--- a/include/linux/page_frag_cache.h
+++ b/include/linux/page_frag_cache.h
@@ -7,6 +7,16 @@
 #include <linux/mm_types_task.h>
 #include <linux/types.h>
 
+static inline void page_frag_cache_init(struct page_frag_cache *nc)
+{
+	nc->va = NULL;
+}
+
+static inline bool page_frag_cache_is_pfmemalloc(struct page_frag_cache *nc)
+{
+	return !!nc->pfmemalloc;
+}
+
 void page_frag_cache_drain(struct page_frag_cache *nc);
 void __page_frag_cache_drain(struct page *page, unsigned int count);
 void *__page_frag_alloc_align(struct page_frag_cache *nc, unsigned int fragsz,
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index de2a044cc665..969e345b0f9c 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -752,14 +752,14 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len,
 	if (in_hardirq() || irqs_disabled()) {
 		nc = this_cpu_ptr(&netdev_alloc_cache);
 		data = page_frag_alloc(nc, len, gfp_mask);
-		pfmemalloc = nc->pfmemalloc;
+		pfmemalloc = page_frag_cache_is_pfmemalloc(nc);
 	} else {
 		local_bh_disable();
 		local_lock_nested_bh(&napi_alloc_cache.bh_lock);
 
 		nc = this_cpu_ptr(&napi_alloc_cache.page);
 		data = page_frag_alloc(nc, len, gfp_mask);
-		pfmemalloc = nc->pfmemalloc;
+		pfmemalloc = page_frag_cache_is_pfmemalloc(nc);
 
 		local_unlock_nested_bh(&napi_alloc_cache.bh_lock);
 		local_bh_enable();
@@ -849,7 +849,7 @@ struct sk_buff *napi_alloc_skb(struct napi_struct *napi, unsigned int len)
 		len = SKB_HEAD_ALIGN(len);
 
 		data = page_frag_alloc(&nc->page, len, gfp_mask);
-		pfmemalloc = nc->page.pfmemalloc;
+		pfmemalloc = page_frag_cache_is_pfmemalloc(&nc->page);
 	}
 	local_unlock_nested_bh(&napi_alloc_cache.bh_lock);
 
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index 1539d315afe7..694c4df7a1a3 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -337,9 +337,7 @@ static void rxrpc_clean_up_connection(struct work_struct *work)
 	 */
 	rxrpc_purge_queue(&conn->rx_queue);
 
-	if (conn->tx_data_alloc.va)
-		__page_frag_cache_drain(virt_to_page(conn->tx_data_alloc.va),
-					conn->tx_data_alloc.pagecnt_bias);
+	page_frag_cache_drain(&conn->tx_data_alloc);
 	call_rcu(&conn->rcu, rxrpc_rcu_free_connection);
 }
 
diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
index 504453c688d7..a8cffe47cf01 100644
--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -452,9 +452,7 @@ void rxrpc_destroy_local(struct rxrpc_local *local)
 #endif
 	rxrpc_purge_queue(&local->rx_queue);
 	rxrpc_purge_client_connections(local);
-	if (local->tx_alloc.va)
-		__page_frag_cache_drain(virt_to_page(local->tx_alloc.va),
-					local->tx_alloc.pagecnt_bias);
+	page_frag_cache_drain(&local->tx_alloc);
 }
 
 /*
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 6b3f01beb294..dcfd84cf0694 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -1609,7 +1609,6 @@ static void svc_tcp_sock_detach(struct svc_xprt *xprt)
 static void svc_sock_free(struct svc_xprt *xprt)
 {
 	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
-	struct page_frag_cache *pfc = &svsk->sk_frag_cache;
 	struct socket *sock = svsk->sk_sock;
 
 	trace_svcsock_free(svsk, sock);
@@ -1619,8 +1618,7 @@ static void svc_sock_free(struct svc_xprt *xprt)
 		sockfd_put(sock);
 	else
 		sock_release(sock);
-	if (pfc->va)
-		__page_frag_cache_drain(virt_to_head_page(pfc->va),
-					pfc->pagecnt_bias);
+
+	page_frag_cache_drain(&svsk->sk_frag_cache);
 	kfree(svsk);
 }
diff --git a/tools/testing/selftests/mm/page_frag/page_frag_test.c b/tools/testing/selftests/mm/page_frag/page_frag_test.c
index 4a009122991e..c52598eaf7e7 100644
--- a/tools/testing/selftests/mm/page_frag/page_frag_test.c
+++ b/tools/testing/selftests/mm/page_frag/page_frag_test.c
@@ -117,7 +117,7 @@ static int __init page_frag_test_init(void)
 	u64 duration;
 	int ret;
 
-	test_frag.va = NULL;
+	page_frag_cache_init(&test_frag);
 	atomic_set(&nthreads, 2);
 	init_completion(&wait);
 
-- 
2.33.0
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