[PATCH 4.2.y-ckt 234/273] net:Add sysctl_max_skb_frags
flat view
STALE3869d
REVIEWED: 2 (0M)
From: Kamal Mostafa <hidden>
Date: 2016-03-07 22:58:42
Also in:
lkml
Subsystem:
networking [general], networking [tcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Neal Cardwell, Linus Torvalds
2 review trailers.
4.2.8-ckt5 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Hans Westgaard Ry <redacted> [ Upstream commit 5f74f82ea34c0da80ea0b49192bb5ea06e063593 ] Devices may have limits on the number of fragments in an skb they support. Current codebase uses a constant as maximum for number of fragments one skb can hold and use. When enabling scatter/gather and running traffic with many small messages the codebase uses the maximum number of fragments and may thereby violate the max for certain devices. The patch introduces a global variable as max number of fragments. Signed-off-by: Hans Westgaard Ry <redacted> Reviewed-by: Håkon Bugge <redacted> Acked-by: Eric Dumazet <redacted> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Kamal Mostafa <redacted> --- include/linux/skbuff.h | 1 + net/core/skbuff.c | 2 ++ net/core/sysctl_net_core.c | 10 ++++++++++ net/ipv4/tcp.c | 4 ++-- 4 files changed, 15 insertions(+), 2 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 8b2a698..777b208 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h@@ -211,6 +211,7 @@ struct sk_buff; #else #define MAX_SKB_FRAGS (65536/PAGE_SIZE + 1) #endif +extern int sysctl_max_skb_frags; typedef struct skb_frag_struct skb_frag_t;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index dd6d553..ae0b23f 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c@@ -79,6 +79,8 @@ struct kmem_cache *skbuff_head_cache __read_mostly; static struct kmem_cache *skbuff_fclone_cache __read_mostly; +int sysctl_max_skb_frags __read_mostly = MAX_SKB_FRAGS; +EXPORT_SYMBOL(sysctl_max_skb_frags); /** * skb_panic - private function for out-of-line support
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 95b6139..a6beb7b 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c@@ -26,6 +26,7 @@ static int zero = 0; static int one = 1; static int min_sndbuf = SOCK_MIN_SNDBUF; static int min_rcvbuf = SOCK_MIN_RCVBUF; +static int max_skb_frags = MAX_SKB_FRAGS; static int net_msg_warn; /* Unused, but still a sysctl */
@@ -392,6 +393,15 @@ static struct ctl_table net_core_table[] = { .mode = 0644, .proc_handler = proc_dointvec }, + { + .procname = "max_skb_frags", + .data = &sysctl_max_skb_frags, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &one, + .extra2 = &max_skb_frags, + }, { } };
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index a7b4cf6..4deb3bb 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c@@ -936,7 +936,7 @@ new_segment: i = skb_shinfo(skb)->nr_frags; can_coalesce = skb_can_coalesce(skb, i, page, offset); - if (!can_coalesce && i >= MAX_SKB_FRAGS) { + if (!can_coalesce && i >= sysctl_max_skb_frags) { tcp_mark_push(tp, skb); goto new_segment; }
@@ -1206,7 +1206,7 @@ new_segment: if (!skb_can_coalesce(skb, i, pfrag->page, pfrag->offset)) { - if (i == MAX_SKB_FRAGS || !sg) { + if (i == sysctl_max_skb_frags || !sg) { tcp_mark_push(tp, skb); goto new_segment; }
--
2.7.0