linux-kernel - [PATCH iproute2 2/2] iplink: double the buffer size also in iplink

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Date:   Fri,  1 Sep 2017 18:39:16 +0200 (CEST)
From:   Michal Kubecek <mkubecek@...e.cz>
To:     Stephen Hemminger <stephen@...workplumber.org>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH iproute2 2/2] iplink: double the buffer size also in
 iplink_get()

Commit 72b365e8e0fd ("libnetlink: Double the dump buffer size") increased
the buffer size for "ip link show" command to 32 KB to handle NICs with
large number of VFs. With "dev" filter, a different code path is taken and
iplink_get() still uses only 16 KB buffer.

The size of 32768 is not very future-proof as NICs supporting 120-128 VFs
are already in use so that single RTM_NEWLINK message in the dump can
exceed 30000 bytes. But it's what rtnl_talk() and rtnl_dump_filter_l() use
so let's be consistent. Once this proves insufficient, all three sizes
should be increased.

Signed-off-by: Michal Kubecek <mkubecek@...e.cz>
---
 ip/iplink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ip/iplink.c b/ip/iplink.c
index 790e3a138bb0..72c347932068 100644
--- a/ip/iplink.c
+++ b/ip/iplink.c
@@ -1024,7 +1024,7 @@ int iplink_get(unsigned int flags, char *name, __u32 filt_mask)
 	};
 	struct {
 		struct nlmsghdr n;
-		char buf[16384];
+		char buf[32768];
 	} answer;

 	if (name) {
-- 
2.14.1