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Commit 745cbcca authored by Andy Grover's avatar Andy Grover Committed by David S. Miller
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RDS: Rewrite connection cleanup, fixing oops on rmmod 



This fixes a bug where a connection was unexpectedly
not on *any* list while being destroyed. It also
cleans up some code duplication and regularizes some
function names.

* Grab appropriate lock in conn_free() and explain in comment
* Ensure via locking that a conn is never not on either
  a dev's list or the nodev list
* Add rds_xx_remove_conn() to match rds_xx_add_conn()
* Make rds_xx_add_conn() return void
* Rename remove_{,nodev_}conns() to
  destroy_{,nodev_}conns() and unify their implementation
  in a helper function
* Document lock ordering as nodev conn_lock before
  dev_conn_lock

Reported-by: default avatarYosef Etigin <yosefe@voltaire.com>
Signed-off-by: default avatarAndy Grover <andy.grover@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f1cffcbf

net/rds/ib.c

+3 −2
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ MODULE_PARM_DESC(fmr_message_size, " Max size of a RDMA transfer"); 


struct list_head rds_ib_devices;



/* NOTE: if also grabbing ibdev lock, grab this first */

DEFINE_SPINLOCK(ib_nodev_conns_lock);

LIST_HEAD(ib_nodev_conns);
@@ -137,7 +138,7 @@ void rds_ib_remove_one(struct ib_device *device) 
		kfree(i_ipaddr);

	}



	rds_ib_remove_conns(rds_ibdev);

	rds_ib_destroy_conns(rds_ibdev);



	if (rds_ibdev->mr_pool)

		rds_ib_destroy_mr_pool(rds_ibdev->mr_pool);
@@ -249,7 +250,7 @@ static int rds_ib_laddr_check(__be32 addr) 
void rds_ib_exit(void)

{

	rds_info_deregister_func(RDS_INFO_IB_CONNECTIONS, rds_ib_ic_info);

	rds_ib_remove_nodev_conns();

	rds_ib_destroy_nodev_conns();

	ib_unregister_client(&rds_ib_client);

	rds_ib_sysctl_exit();

	rds_ib_recv_exit();

net/rds/ib.h

+11 −3
Original line number Diff line number Diff line
@@ -267,9 +267,17 @@ void rds_ib_cm_connect_complete(struct rds_connection *conn, 


/* ib_rdma.c */

int rds_ib_update_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr);

int rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn);

void rds_ib_remove_nodev_conns(void);

void rds_ib_remove_conns(struct rds_ib_device *rds_ibdev);

void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn);

void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn);

void __rds_ib_destroy_conns(struct list_head *list, spinlock_t *list_lock);

static inline void rds_ib_destroy_nodev_conns(void)

{

	__rds_ib_destroy_conns(&ib_nodev_conns, &ib_nodev_conns_lock);

}

static inline void rds_ib_destroy_conns(struct rds_ib_device *rds_ibdev)

{

	__rds_ib_destroy_conns(&rds_ibdev->conn_list, &rds_ibdev->spinlock);

}

struct rds_ib_mr_pool *rds_ib_create_mr_pool(struct rds_ib_device *);

void rds_ib_get_mr_info(struct rds_ib_device *rds_ibdev, struct rds_info_rdma_connection *iinfo);

void rds_ib_destroy_mr_pool(struct rds_ib_mr_pool *);

net/rds/ib_cm.c

+19 −15
Original line number Diff line number Diff line
@@ -126,9 +126,7 @@ void rds_ib_cm_connect_complete(struct rds_connection *conn, struct rdma_cm_even 
	err = rds_ib_update_ipaddr(rds_ibdev, conn->c_laddr);

	if (err)

		printk(KERN_ERR "rds_ib_update_ipaddr failed (%d)\n", err);

	err = rds_ib_add_conn(rds_ibdev, conn);

	if (err)

		printk(KERN_ERR "rds_ib_add_conn failed (%d)\n", err);

	rds_ib_add_conn(rds_ibdev, conn);



	/* If the peer gave us the last packet it saw, process this as if

	 * we had received a regular ACK. */
@@ -616,18 +614,8 @@ void rds_ib_conn_shutdown(struct rds_connection *conn) 
		/*

		 * Move connection back to the nodev list.

		 */

		if (ic->rds_ibdev) {



			spin_lock_irq(&ic->rds_ibdev->spinlock);

			BUG_ON(list_empty(&ic->ib_node));

			list_del(&ic->ib_node);

			spin_unlock_irq(&ic->rds_ibdev->spinlock);



			spin_lock_irq(&ib_nodev_conns_lock);

			list_add_tail(&ic->ib_node, &ib_nodev_conns);

			spin_unlock_irq(&ib_nodev_conns_lock);

			ic->rds_ibdev = NULL;

		}

		if (ic->rds_ibdev)

			rds_ib_remove_conn(ic->rds_ibdev, conn);



		ic->i_cm_id = NULL;

		ic->i_pd = NULL;
@@ -701,11 +689,27 @@ int rds_ib_conn_alloc(struct rds_connection *conn, gfp_t gfp) 
	return 0;

}



/*

 * Free a connection. Connection must be shut down and not set for reconnect.

 */

void rds_ib_conn_free(void *arg)

{

	struct rds_ib_connection *ic = arg;

	spinlock_t	*lock_ptr;



	rdsdebug("ic %p\n", ic);



	/*

	 * Conn is either on a dev's list or on the nodev list.

	 * A race with shutdown() or connect() would cause problems

	 * (since rds_ibdev would change) but that should never happen.

	 */

	lock_ptr = ic->rds_ibdev ? &ic->rds_ibdev->spinlock : &ib_nodev_conns_lock;



	spin_lock_irq(lock_ptr);

	list_del(&ic->ib_node);

	spin_unlock_irq(lock_ptr);



	kfree(ic);

}

net/rds/ib_rdma.c

+21 −22
Original line number Diff line number Diff line
@@ -139,7 +139,7 @@ int rds_ib_update_ipaddr(struct rds_ib_device *rds_ibdev, __be32 ipaddr) 
	return rds_ib_add_ipaddr(rds_ibdev, ipaddr);

}



int rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)

void rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)

{

	struct rds_ib_connection *ic = conn->c_transport_data;
@@ -148,45 +148,44 @@ int rds_ib_add_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn 
	BUG_ON(list_empty(&ib_nodev_conns));

	BUG_ON(list_empty(&ic->ib_node));

	list_del(&ic->ib_node);

	spin_unlock_irq(&ib_nodev_conns_lock);



	spin_lock_irq(&rds_ibdev->spinlock);

	list_add_tail(&ic->ib_node, &rds_ibdev->conn_list);

	spin_unlock_irq(&rds_ibdev->spinlock);

	spin_unlock_irq(&ib_nodev_conns_lock);



	ic->rds_ibdev = rds_ibdev;



	return 0;

}



void rds_ib_remove_nodev_conns(void)

void rds_ib_remove_conn(struct rds_ib_device *rds_ibdev, struct rds_connection *conn)

{

	struct rds_ib_connection *ic, *_ic;

	LIST_HEAD(tmp_list);

	struct rds_ib_connection *ic = conn->c_transport_data;



	/* avoid calling conn_destroy with irqs off */

	spin_lock_irq(&ib_nodev_conns_lock);

	list_splice(&ib_nodev_conns, &tmp_list);

	INIT_LIST_HEAD(&ib_nodev_conns);

	spin_unlock_irq(&ib_nodev_conns_lock);

	/* place conn on nodev_conns_list */

	spin_lock(&ib_nodev_conns_lock);



	list_for_each_entry_safe(ic, _ic, &tmp_list, ib_node) {

		if (ic->conn->c_passive)

			rds_conn_destroy(ic->conn->c_passive);

		rds_conn_destroy(ic->conn);

	}

	spin_lock_irq(&rds_ibdev->spinlock);

	BUG_ON(list_empty(&ic->ib_node));

	list_del(&ic->ib_node);

	spin_unlock_irq(&rds_ibdev->spinlock);



	list_add_tail(&ic->ib_node, &ib_nodev_conns);



	spin_unlock(&ib_nodev_conns_lock);



	ic->rds_ibdev = NULL;

}



void rds_ib_remove_conns(struct rds_ib_device *rds_ibdev)

void __rds_ib_destroy_conns(struct list_head *list, spinlock_t *list_lock)

{

	struct rds_ib_connection *ic, *_ic;

	LIST_HEAD(tmp_list);



	/* avoid calling conn_destroy with irqs off */

	spin_lock_irq(&rds_ibdev->spinlock);

	list_splice(&rds_ibdev->conn_list, &tmp_list);

	INIT_LIST_HEAD(&rds_ibdev->conn_list);

	spin_unlock_irq(&rds_ibdev->spinlock);

	spin_lock_irq(list_lock);

	list_splice(list, &tmp_list);

	INIT_LIST_HEAD(list);

	spin_unlock_irq(list_lock);



	list_for_each_entry_safe(ic, _ic, &tmp_list, ib_node) {

		if (ic->conn->c_passive)

net/rds/iw.c

+3 −2
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ MODULE_PARM_DESC(fastreg_message_size, " Max size of a RDMA transfer (fastreg MR 


struct list_head rds_iw_devices;



/* NOTE: if also grabbing iwdev lock, grab this first */

DEFINE_SPINLOCK(iw_nodev_conns_lock);

LIST_HEAD(iw_nodev_conns);
@@ -145,7 +146,7 @@ void rds_iw_remove_one(struct ib_device *device) 
	}

	spin_unlock_irq(&rds_iwdev->spinlock);



	rds_iw_remove_conns(rds_iwdev);

	rds_iw_destroy_conns(rds_iwdev);



	if (rds_iwdev->mr_pool)

		rds_iw_destroy_mr_pool(rds_iwdev->mr_pool);
@@ -258,7 +259,7 @@ static int rds_iw_laddr_check(__be32 addr) 
void rds_iw_exit(void)

{

	rds_info_deregister_func(RDS_INFO_IWARP_CONNECTIONS, rds_iw_ic_info);

	rds_iw_remove_nodev_conns();

	rds_iw_destroy_nodev_conns();

	ib_unregister_client(&rds_iw_client);

	rds_iw_sysctl_exit();

	rds_iw_recv_exit();