From ee291e63293146db64668e8d65eb35c97e8324f4 Mon Sep 17 00:00:00 2001 From: Andy Grover Date: Fri, 24 Jan 2014 16:18:54 -0800 Subject: [PATCH] target/iscsi: Fix network portal creation race 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 Cc: #3.1+ Signed-off-by: Nicholas Bellinger --- 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 2a52752a9937..a99637e9e820 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; @@ -307,6 +307,9 @@ bool iscsit_check_np_match( return false; } +/* + * Called with mutex np_lock held + */ static struct iscsi_np *iscsit_get_np( struct __kernel_sockaddr_storage *sockaddr, int network_transport) @@ -314,11 +317,10 @@ static struct iscsi_np *iscsit_get_np( struct iscsi_np *np; bool match; - 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; } @@ -330,13 +332,11 @@ 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; } @@ -350,16 +350,22 @@ 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); } @@ -382,6 +388,7 @@ 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); } @@ -390,6 +397,7 @@ 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); } /* @@ -400,10 +408,10 @@ 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_transport->name); @@ -469,9 +477,9 @@ int iscsit_del_np(struct iscsi_np *np) np->np_transport->iscsit_free_np(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_transport->name);