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Date: Thu, 5 Nov 2015 15:07:44 -0500
From: Sasha Levin <sasha.levin@...cle.com>
To: xeb@...l.ru
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
Sasha Levin <sasha.levin@...cle.com>
Subject: [PATCH] pptp: use idr for allocation of callids
The current implementation used a bitfield with a corresponding array to
manage assignment of call ids. Rather than open-coding it, use IDR for
this.
Signed-off-by: Sasha Levin <sasha.levin@...cle.com>
---
drivers/net/ppp/pptp.c | 67 +++++++++++++++++++++---------------------------
1 file changed, 29 insertions(+), 38 deletions(-)
diff --git a/drivers/net/ppp/pptp.c b/drivers/net/ppp/pptp.c
index fc69e41..4637314 100644
--- a/drivers/net/ppp/pptp.c
+++ b/drivers/net/ppp/pptp.c
@@ -30,6 +30,7 @@
#include <linux/ip.h>
#include <linux/rcupdate.h>
#include <linux/spinlock.h>
+#include <linux/idr.h>
#include <net/sock.h>
#include <net/protocol.h>
@@ -43,10 +44,7 @@
#define PPTP_DRIVER_VERSION "0.8.5"
#define MAX_CALLID 65535
-
-static DECLARE_BITMAP(callid_bitmap, MAX_CALLID + 1);
-static struct pppox_sock __rcu **callid_sock;
-
+static struct idr callid;
static DEFINE_SPINLOCK(chan_lock);
static struct proto pptp_sk_proto __read_mostly;
@@ -94,7 +92,7 @@ static struct pppox_sock *lookup_chan(u16 call_id, __be32 s_addr)
struct pptp_opt *opt;
rcu_read_lock();
- sock = rcu_dereference(callid_sock[call_id]);
+ sock = idr_find(&callid, call_id);
if (sock) {
opt = &sock->proto.pptp;
if (opt->dst_addr.sin_addr.s_addr != s_addr)
@@ -107,60 +105,55 @@ static struct pppox_sock *lookup_chan(u16 call_id, __be32 s_addr)
return sock;
}
-static int lookup_chan_dst(u16 call_id, __be32 d_addr)
+static bool lookup_chan_dst(u16 call_id, __be32 d_addr)
{
struct pppox_sock *sock;
struct pptp_opt *opt;
int i;
+ bool found = false;
rcu_read_lock();
- i = 1;
- for_each_set_bit_from(i, callid_bitmap, MAX_CALLID) {
- sock = rcu_dereference(callid_sock[i]);
- if (!sock)
- continue;
+ idr_for_each_entry(&callid, sock, i) {
opt = &sock->proto.pptp;
if (opt->dst_addr.call_id == call_id &&
- opt->dst_addr.sin_addr.s_addr == d_addr)
+ opt->dst_addr.sin_addr.s_addr == d_addr) {
+ found = true;
break;
+ }
}
rcu_read_unlock();
- return i < MAX_CALLID;
+ return found;
}
static int add_chan(struct pppox_sock *sock)
{
- static int call_id;
+ int ret, requested;
- spin_lock(&chan_lock);
- if (!sock->proto.pptp.src_addr.call_id) {
- call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, call_id + 1);
- if (call_id == MAX_CALLID) {
- call_id = find_next_zero_bit(callid_bitmap, MAX_CALLID, 1);
- if (call_id == MAX_CALLID)
- goto out_err;
- }
- sock->proto.pptp.src_addr.call_id = call_id;
- } else if (test_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap))
- goto out_err;
+ idr_preload(GFP_KERNEL);
- set_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap);
- rcu_assign_pointer(callid_sock[sock->proto.pptp.src_addr.call_id], sock);
+ spin_lock(&chan_lock);
+ requested = sock->proto.pptp.src_addr.call_id;
+ if (!requested)
+ ret = idr_alloc(&callid, sock, 1, MAX_CALLID, GFP_ATOMIC);
+ else
+ ret = idr_alloc(&callid, sock, requested, requested + 1, GFP_ATOMIC);
spin_unlock(&chan_lock);
- return 0;
+ idr_preload_end();
-out_err:
- spin_unlock(&chan_lock);
- return -1;
+ return ret;
}
static void del_chan(struct pppox_sock *sock)
{
spin_lock(&chan_lock);
- clear_bit(sock->proto.pptp.src_addr.call_id, callid_bitmap);
- RCU_INIT_POINTER(callid_sock[sock->proto.pptp.src_addr.call_id], NULL);
+ /*
+ * It's possible the sock was created but never bound, let's verify
+ * that this isn't the case before blindly deleting a different sock.
+ */
+ if (idr_find(&callid, sock->proto.pptp.src_addr.call_id) == sock)
+ idr_remove(&callid, sock->proto.pptp.src_addr.call_id);
spin_unlock(&chan_lock);
synchronize_rcu();
}
@@ -670,9 +663,7 @@ static int __init pptp_init_module(void)
int err = 0;
pr_info("PPTP driver version " PPTP_DRIVER_VERSION "\n");
- callid_sock = vzalloc((MAX_CALLID + 1) * sizeof(void *));
- if (!callid_sock)
- return -ENOMEM;
+ idr_init(&callid);
err = gre_add_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
if (err) {
@@ -699,7 +690,7 @@ out_unregister_sk_proto:
out_gre_del_protocol:
gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
out_mem_free:
- vfree(callid_sock);
+ idr_destroy(&callid);
return err;
}
@@ -709,7 +700,7 @@ static void __exit pptp_exit_module(void)
unregister_pppox_proto(PX_PROTO_PPTP);
proto_unregister(&pptp_sk_proto);
gre_del_protocol(&gre_pptp_protocol, GREPROTO_PPTP);
- vfree(callid_sock);
+ idr_destroy(&callid);
}
module_init(pptp_init_module);
--
1.7.10.4
--
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