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Message-Id: <1392061264-28124-105-git-send-email-kamal@canonical.com>
Date: Mon, 10 Feb 2014 11:40:44 -0800
From: Kamal Mostafa <kamal@...onical.com>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org,
kernel-team@...ts.ubuntu.com
Cc: Andy Grover <agrover@...hat.com>,
Nicholas Bellinger <nab@...ux-iscsi.org>,
Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 3.8 104/124] target/iscsi: Fix network portal creation race
3.8.13.18 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Andy Grover <agrover@...hat.com>
commit ee291e63293146db64668e8d65eb35c97e8324f4 upstream.
When creating network portals rapidly, such as when restoring a
configuration, LIO's code to reuse existing portals can return a false
negative if the thread hasn't run yet and set np_thread_state to
ISCSI_NP_THREAD_ACTIVE. This causes an error in the network stack
when attempting to bind to the same address/port.
This patch sets NP_THREAD_ACTIVE before the np is placed on g_np_list,
so even if the thread hasn't run yet, iscsit_get_np will return the
existing np.
Also, convert np_lock -> np_mutex + hold across adding new net portal
to g_np_list to prevent a race where two threads may attempt to create
the same network portal, resulting in one of them failing.
(nab: Add missing mutex_unlocks in iscsit_add_np failure paths)
(DanC: Fix incorrect spin_unlock -> spin_unlock_bh)
Signed-off-by: Andy Grover <agrover@...hat.com>
Signed-off-by: Nicholas Bellinger <nab@...ux-iscsi.org>
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
drivers/target/iscsi/iscsi_target.c | 34 +++++++++++++++++++++-------------
1 file changed, 21 insertions(+), 13 deletions(-)
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 7b83945..b489363 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -52,7 +52,7 @@
static LIST_HEAD(g_tiqn_list);
static LIST_HEAD(g_np_list);
static DEFINE_SPINLOCK(tiqn_lock);
-static DEFINE_SPINLOCK(np_lock);
+static DEFINE_MUTEX(np_lock);
static struct idr tiqn_idr;
struct idr sess_idr;
@@ -264,6 +264,9 @@ int iscsit_deaccess_np(struct iscsi_np *np, struct iscsi_portal_group *tpg)
return 0;
}
+/*
+ * Called with mutex np_lock held
+ */
static struct iscsi_np *iscsit_get_np(
struct __kernel_sockaddr_storage *sockaddr,
int network_transport)
@@ -274,11 +277,10 @@ static struct iscsi_np *iscsit_get_np(
int ip_match = 0;
u16 port;
- spin_lock_bh(&np_lock);
list_for_each_entry(np, &g_np_list, np_list) {
- spin_lock(&np->np_thread_lock);
+ spin_lock_bh(&np->np_thread_lock);
if (np->np_thread_state != ISCSI_NP_THREAD_ACTIVE) {
- spin_unlock(&np->np_thread_lock);
+ spin_unlock_bh(&np->np_thread_lock);
continue;
}
@@ -311,13 +313,11 @@ static struct iscsi_np *iscsit_get_np(
* while iscsi_tpg_add_network_portal() is called.
*/
np->np_exports++;
- spin_unlock(&np->np_thread_lock);
- spin_unlock_bh(&np_lock);
+ spin_unlock_bh(&np->np_thread_lock);
return np;
}
- spin_unlock(&np->np_thread_lock);
+ spin_unlock_bh(&np->np_thread_lock);
}
- spin_unlock_bh(&np_lock);
return NULL;
}
@@ -331,16 +331,22 @@ struct iscsi_np *iscsit_add_np(
struct sockaddr_in6 *sock_in6;
struct iscsi_np *np;
int ret;
+
+ mutex_lock(&np_lock);
+
/*
* Locate the existing struct iscsi_np if already active..
*/
np = iscsit_get_np(sockaddr, network_transport);
- if (np)
+ if (np) {
+ mutex_unlock(&np_lock);
return np;
+ }
np = kzalloc(sizeof(struct iscsi_np), GFP_KERNEL);
if (!np) {
pr_err("Unable to allocate memory for struct iscsi_np\n");
+ mutex_unlock(&np_lock);
return ERR_PTR(-ENOMEM);
}
@@ -363,6 +369,7 @@ struct iscsi_np *iscsit_add_np(
ret = iscsi_target_setup_login_socket(np, sockaddr);
if (ret != 0) {
kfree(np);
+ mutex_unlock(&np_lock);
return ERR_PTR(ret);
}
@@ -371,6 +378,7 @@ struct iscsi_np *iscsit_add_np(
pr_err("Unable to create kthread: iscsi_np\n");
ret = PTR_ERR(np->np_thread);
kfree(np);
+ mutex_unlock(&np_lock);
return ERR_PTR(ret);
}
/*
@@ -381,10 +389,10 @@ struct iscsi_np *iscsit_add_np(
* point because iscsi_np has not been added to g_np_list yet.
*/
np->np_exports = 1;
+ np->np_thread_state = ISCSI_NP_THREAD_ACTIVE;
- spin_lock_bh(&np_lock);
list_add_tail(&np->np_list, &g_np_list);
- spin_unlock_bh(&np_lock);
+ mutex_unlock(&np_lock);
pr_debug("CORE[0] - Added Network Portal: %s:%hu on %s\n",
np->np_ip, np->np_port, (np->np_network_transport == ISCSI_TCP) ?
@@ -455,9 +463,9 @@ int iscsit_del_np(struct iscsi_np *np)
}
iscsit_del_np_comm(np);
- spin_lock_bh(&np_lock);
+ mutex_lock(&np_lock);
list_del(&np->np_list);
- spin_unlock_bh(&np_lock);
+ mutex_unlock(&np_lock);
pr_debug("CORE[0] - Removed Network Portal: %s:%hu on %s\n",
np->np_ip, np->np_port, (np->np_network_transport == ISCSI_TCP) ?
--
1.8.3.2
--
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