netprio builds per-netdev contiguous priomap array which is indexed by
css->id. The array is allocated using kzalloc() effectively limiting
the maximum ID supported to some thousand range. This patch caps the
maximum supported css->id to USHRT_MAX which should be way above what
is actually useable.
This allows reducing sock->sk_cgrp_prioidx to u16 from u32. The freed
up part will be used to overload the cgroup related fields.
sock->sk_cgrp_prioidx's position is swapped with sk_mark so that the
two cgroup related fields are adjacent.
Signed-off-by: Tejun Heo <t...@kernel.org>
Acked-by: Daniel Wagner <daniel.wag...@bmw-carit.de>
Cc: Daniel Borkmann <dan...@iogearbox.net>
CC: Neil Horman <nhor...@tuxdriver.com>
---
include/net/sock.h | 10 +++++-----
net/core/netprio_cgroup.c | 9 +++++++++
2 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index bbf7c2c..b517351 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -288,7 +288,6 @@ struct cg_proto;
* @sk_ack_backlog: current listen backlog
* @sk_max_ack_backlog: listen backlog set in listen()
* @sk_priority: %SO_PRIORITY setting
- * @sk_cgrp_prioidx: socket group's priority map index
* @sk_type: socket type (%SOCK_STREAM, etc)
* @sk_protocol: which protocol this socket belongs in this network family
* @sk_peer_pid: &struct pid for this socket's peer
@@ -309,6 +308,7 @@ struct cg_proto;
* @sk_send_head: front of stuff to transmit
* @sk_security: used by security modules
* @sk_mark: generic packet mark
+ * @sk_cgrp_prioidx: socket group's priority map index
* @sk_classid: this socket's cgroup classid
* @sk_cgrp: this socket's cgroup-specific proto data
* @sk_write_pending: a write to stream socket waits to start
@@ -423,9 +423,7 @@ struct sock {
u32 sk_ack_backlog;
u32 sk_max_ack_backlog;
__u32 sk_priority;
-#if IS_ENABLED(CONFIG_CGROUP_NET_PRIO)
- __u32 sk_cgrp_prioidx;
-#endif
+ __u32 sk_mark;
struct pid *sk_peer_pid;
const struct cred *sk_peer_cred;
long sk_rcvtimeo;
@@ -443,7 +441,9 @@ struct sock {
#ifdef CONFIG_SECURITY
void *sk_security;
#endif
- __u32 sk_mark;
+#if IS_ENABLED(CONFIG_CGROUP_NET_PRIO)
+ u16 sk_cgrp_prioidx;
+#endif
#ifdef CONFIG_CGROUP_NET_CLASSID
u32 sk_classid;
#endif
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index cbd0a19..2b9159b 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -27,6 +27,12 @@
#include <linux/fdtable.h>
+/*
+ * netprio allocates per-net_device priomap array which is indexed by
+ * css->id. Limiting css ID to 16bits doesn't lose anything.
+ */
+#define NETPRIO_ID_MAX USHRT_MAX
+
#define PRIOMAP_MIN_SZ 128
/*
@@ -144,6 +150,9 @@ static int cgrp_css_online(struct cgroup_subsys_state *css)
struct net_device *dev;
int ret = 0;
+ if (css->id > NETPRIO_ID_MAX)
+ return -ENOSPC;
+
if (!parent_css)
return 0;
--
2.5.0
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