| From f466eb46a029021e2a49c9b5dc6d2e1666e46098 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Sun, 27 Jun 2021 23:37:44 -0700 |
| Subject: net: tipc: fix FB_MTU eat two pages |
| |
| From: Menglong Dong <dong.menglong@zte.com.cn> |
| |
| [ Upstream commit 0c6de0c943dbb42831bf7502eb5c007f71e752d2 ] |
| |
| FB_MTU is used in 'tipc_msg_build()' to alloc smaller skb when memory |
| allocation fails, which can avoid unnecessary sending failures. |
| |
| The value of FB_MTU now is 3744, and the data size will be: |
| |
| (3744 + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) + \ |
| SKB_DATA_ALIGN(BUF_HEADROOM + BUF_TAILROOM + 3)) |
| |
| which is larger than one page(4096), and two pages will be allocated. |
| |
| To avoid it, replace '3744' with a calculation: |
| |
| (PAGE_SIZE - SKB_DATA_ALIGN(BUF_OVERHEAD) - \ |
| SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) |
| |
| What's more, alloc_skb_fclone() will call SKB_DATA_ALIGN for data size, |
| and it's not necessary to make alignment for buf_size in |
| tipc_buf_acquire(). So, just remove it. |
| |
| Fixes: 4c94cc2d3d57 ("tipc: fall back to smaller MTU if allocation of local send skb fails") |
| Signed-off-by: Menglong Dong <dong.menglong@zte.com.cn> |
| Acked-by: Jon Maloy <jmaloy@redhat.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/tipc/bcast.c | 2 +- |
| net/tipc/msg.c | 17 ++++++++--------- |
| net/tipc/msg.h | 3 ++- |
| 3 files changed, 11 insertions(+), 11 deletions(-) |
| |
| diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c |
| index d4beca895992..593846d25214 100644 |
| --- a/net/tipc/bcast.c |
| +++ b/net/tipc/bcast.c |
| @@ -699,7 +699,7 @@ int tipc_bcast_init(struct net *net) |
| spin_lock_init(&tipc_net(net)->bclock); |
| |
| if (!tipc_link_bc_create(net, 0, 0, NULL, |
| - FB_MTU, |
| + one_page_mtu, |
| BCLINK_WIN_DEFAULT, |
| BCLINK_WIN_DEFAULT, |
| 0, |
| diff --git a/net/tipc/msg.c b/net/tipc/msg.c |
| index 88a3ed80094c..91dcf648d32b 100644 |
| --- a/net/tipc/msg.c |
| +++ b/net/tipc/msg.c |
| @@ -44,12 +44,15 @@ |
| #define MAX_FORWARD_SIZE 1024 |
| #ifdef CONFIG_TIPC_CRYPTO |
| #define BUF_HEADROOM ALIGN(((LL_MAX_HEADER + 48) + EHDR_MAX_SIZE), 16) |
| -#define BUF_TAILROOM (TIPC_AES_GCM_TAG_SIZE) |
| +#define BUF_OVERHEAD (BUF_HEADROOM + TIPC_AES_GCM_TAG_SIZE) |
| #else |
| #define BUF_HEADROOM (LL_MAX_HEADER + 48) |
| -#define BUF_TAILROOM 16 |
| +#define BUF_OVERHEAD BUF_HEADROOM |
| #endif |
| |
| +const int one_page_mtu = PAGE_SIZE - SKB_DATA_ALIGN(BUF_OVERHEAD) - |
| + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); |
| + |
| static unsigned int align(unsigned int i) |
| { |
| return (i + 3) & ~3u; |
| @@ -67,13 +70,8 @@ static unsigned int align(unsigned int i) |
| struct sk_buff *tipc_buf_acquire(u32 size, gfp_t gfp) |
| { |
| struct sk_buff *skb; |
| -#ifdef CONFIG_TIPC_CRYPTO |
| - unsigned int buf_size = (BUF_HEADROOM + size + BUF_TAILROOM + 3) & ~3u; |
| -#else |
| - unsigned int buf_size = (BUF_HEADROOM + size + 3) & ~3u; |
| -#endif |
| |
| - skb = alloc_skb_fclone(buf_size, gfp); |
| + skb = alloc_skb_fclone(BUF_OVERHEAD + size, gfp); |
| if (skb) { |
| skb_reserve(skb, BUF_HEADROOM); |
| skb_put(skb, size); |
| @@ -395,7 +393,8 @@ int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, int offset, |
| if (unlikely(!skb)) { |
| if (pktmax != MAX_MSG_SIZE) |
| return -ENOMEM; |
| - rc = tipc_msg_build(mhdr, m, offset, dsz, FB_MTU, list); |
| + rc = tipc_msg_build(mhdr, m, offset, dsz, |
| + one_page_mtu, list); |
| if (rc != dsz) |
| return rc; |
| if (tipc_msg_assemble(list)) |
| diff --git a/net/tipc/msg.h b/net/tipc/msg.h |
| index 5d64596ba987..64ae4c4c44f8 100644 |
| --- a/net/tipc/msg.h |
| +++ b/net/tipc/msg.h |
| @@ -99,9 +99,10 @@ struct plist; |
| #define MAX_H_SIZE 60 /* Largest possible TIPC header size */ |
| |
| #define MAX_MSG_SIZE (MAX_H_SIZE + TIPC_MAX_USER_MSG_SIZE) |
| -#define FB_MTU 3744 |
| #define TIPC_MEDIA_INFO_OFFSET 5 |
| |
| +extern const int one_page_mtu; |
| + |
| struct tipc_skb_cb { |
| union { |
| struct { |
| -- |
| 2.30.2 |
| |