[openib-general] [PATCH] change iser ib connection state management
Or Gerlitz
ogerlitz at voltaire.com
Thu May 4 06:09:31 PDT 2006
Sean,
This is the patch i just sent to openib and lkml, i see now that the other
email had some line wrapping problems, so here's again.
Or.
r6924 | ogerlitz | 2006-05-04 16:03:21 +0300 (Thu, 04 May 2006) | 7 lines
changed iser ib conn state management to be done with an int variable
keeping the state and a lock. When a related race is possible the lock is
used to check (comp) or change (comp_exch) the state. When no race can
happen the state is just examined or changed.
Signed-off-by: Or Gerlitz <ogerlitz at voltaire.com
Index: iscsi_iser.h
===================================================================
--- iscsi_iser.h (revision 6900)
+++ iscsi_iser.h (revision 6924)
@@ -235,7 +235,8 @@ struct iser_device {
struct iser_conn
{
struct iscsi_iser_conn *iser_conn; /* iser conn for upcalls */
- atomic_t state; /* rdma connection state */
+ enum iser_ib_conn_state state; /* rdma connection state */
+ spinlock_t lock; /* used for state changes */
struct iser_device *device; /* device context */
struct rdma_cm_id *cma_id; /* CMA ID */
struct ib_qp *qp; /* QP */
@@ -352,4 +353,7 @@ void iser_unreg_mem(struct iser_mem_reg
int iser_post_recv(struct iser_desc *rx_desc);
int iser_post_send(struct iser_desc *tx_desc);
+
+int iser_conn_state_comp(struct iser_conn *ib_conn,
+ enum iser_ib_conn_state comp);
#endif
Index: iser_verbs.c
===================================================================
--- iser_verbs.c (revision 6900)
+++ iser_verbs.c (revision 6924)
@@ -287,6 +287,30 @@ static void iser_device_try_release(stru
mutex_unlock(&ig.device_list_mutex);
}
+int iser_conn_state_comp(struct iser_conn *ib_conn,
+ enum iser_ib_conn_state comp)
+{
+ int ret;
+
+ spin_lock_bh(&ib_conn->lock);
+ ret = (ib_conn->state == comp);
+ spin_unlock_bh(&ib_conn->lock);
+ return ret;
+}
+
+static int iser_conn_state_comp_exch(struct iser_conn *ib_conn,
+ enum iser_ib_conn_state comp,
+ enum iser_ib_conn_state exch)
+{
+ int ret;
+
+ spin_lock_bh(&ib_conn->lock);
+ if ((ret = (ib_conn->state == comp)))
+ ib_conn->state = exch;
+ spin_unlock_bh(&ib_conn->lock);
+ return ret;
+}
+
/**
* triggers start of the disconnect procedures and wait for them to be done
*/
@@ -294,12 +318,17 @@ void iser_conn_terminate(struct iser_con
{
int err = 0;
- atomic_set(&ib_conn->state, ISER_CONN_TERMINATING);
- err = rdma_disconnect(ib_conn->cma_id);
- if (err)
- iser_bug("Failed to disconnect, conn: 0x%p err %d\n",ib_conn,err);
+ if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
+ ISER_CONN_TERMINATING)) {
+ err = rdma_disconnect(ib_conn->cma_id);
+ if (err)
+ iser_err("Failed to disconnect, conn: 0x%p err %d\n",
+ ib_conn,err);
+
+ }
+
wait_event_interruptible(ib_conn->wait,
- (atomic_read(&ib_conn->state) == ISER_CONN_DOWN));
+ ib_conn->state == ISER_CONN_DOWN);
iser_conn_release(ib_conn);
}
@@ -309,7 +338,7 @@ static void iser_connect_error(struct rd
struct iser_conn *ib_conn;
ib_conn = (struct iser_conn *)cma_id->context;
- atomic_set(&ib_conn->state, ISER_CONN_DOWN);
+ ib_conn->state = ISER_CONN_DOWN;
wake_up_interruptible(&ib_conn->wait);
}
@@ -369,7 +398,7 @@ static void iser_connected_handler(struc
struct iser_conn *ib_conn;
ib_conn = (struct iser_conn *)cma_id->context;
- atomic_set(&ib_conn->state, ISER_CONN_UP);
+ ib_conn->state = ISER_CONN_UP;
wake_up_interruptible(&ib_conn->wait);
}
@@ -380,17 +409,17 @@ static void iser_disconnected_handler(st
ib_conn = (struct iser_conn *)cma_id->context;
ib_conn->disc_evt_flag = 1;
- /* If this event is unsolicited this means that the conn is being */
- /* terminated asynchronously from the iSCSI layer's perspective. */
- if (atomic_read(&ib_conn->state) == ISER_CONN_UP) {
- atomic_set(&ib_conn->state, ISER_CONN_TERMINATING);
+ /* getting here when the state is UP means that the conn is being *
+ * terminated asynchronously from the iSCSI layer's perspective. */
+ if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
+ ISER_CONN_TERMINATING))
iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
ISCSI_ERR_CONN_FAILED);
- }
+
/* Complete the termination process if no posts are pending */
if ((atomic_read(&ib_conn->post_recv_buf_count) == 0) &&
(atomic_read(&ib_conn->post_send_buf_count) == 0)) {
- atomic_set(&ib_conn->state, ISER_CONN_DOWN);
+ ib_conn->state = ISER_CONN_DOWN;
wake_up_interruptible(&ib_conn->wait);
}
}
@@ -444,13 +473,14 @@ int iser_conn_init(struct iser_conn **ib
iser_err("can't alloc memory for struct iser_conn\n");
return -ENOMEM;
}
- atomic_set(&ib_conn->state, ISER_CONN_INIT);
+ ib_conn->state = ISER_CONN_INIT;
init_waitqueue_head(&ib_conn->wait);
atomic_set(&ib_conn->post_recv_buf_count, 0);
atomic_set(&ib_conn->post_send_buf_count, 0);
INIT_WORK(&ib_conn->comperror_work, iser_comp_error_worker,
ib_conn);
INIT_LIST_HEAD(&ib_conn->conn_list);
+ spin_lock_init(&ib_conn->lock);
*ibconn = ib_conn;
return 0;
@@ -477,7 +507,7 @@ int iser_connect(struct iser_conn *ib_
iser_err("connecting to: %d.%d.%d.%d, port 0x%x\n",
NIPQUAD(dst_addr->sin_addr), dst_addr->sin_port);
- atomic_set(&ib_conn->state, ISER_CONN_PENDING);
+ ib_conn->state = ISER_CONN_PENDING;
ib_conn->cma_id = rdma_create_id(iser_cma_handler,
(void *)ib_conn,
@@ -498,9 +528,9 @@ int iser_connect(struct iser_conn *ib_
if (!non_blocking) {
wait_event_interruptible(ib_conn->wait,
- atomic_read(&ib_conn->state) != ISER_CONN_PENDING);
+ (ib_conn->state != ISER_CONN_PENDING));
- if (atomic_read(&ib_conn->state) != ISER_CONN_UP) {
+ if (ib_conn->state != ISER_CONN_UP) {
err = -EIO;
goto connect_failure;
}
@@ -514,7 +544,7 @@ int iser_connect(struct iser_conn *ib_
id_failure:
ib_conn->cma_id = NULL;
addr_failure:
- atomic_set(&ib_conn->state, ISER_CONN_DOWN);
+ ib_conn->state = ISER_CONN_DOWN;
connect_failure:
iser_conn_release(ib_conn);
return err;
@@ -527,7 +557,7 @@ void iser_conn_release(struct iser_conn
{
struct iser_device *device = ib_conn->device;
- BUG_ON(atomic_read(&ib_conn->state) != ISER_CONN_DOWN);
+ BUG_ON(ib_conn->state != ISER_CONN_DOWN);
mutex_lock(&ig.connlist_mutex);
list_del(&ib_conn->conn_list);
@@ -719,16 +749,17 @@ static void iser_comp_error_worker(void
{
struct iser_conn *ib_conn = data;
- if (atomic_read(&ib_conn->state) == ISER_CONN_UP) {
- atomic_set(&ib_conn->state, ISER_CONN_TERMINATING);
+ /* getting here when the state is UP means that the conn is being *
+ * terminated asynchronously from the iSCSI layer's perspective. */
+ if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
+ ISER_CONN_TERMINATING))
iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
ISCSI_ERR_CONN_FAILED);
- }
/* complete the termination process if disconnect event was delivered *
* note there are no more non completed posts to the QP */
if (ib_conn->disc_evt_flag) {
- atomic_set(&ib_conn->state, ISER_CONN_DOWN);
+ ib_conn->state = ISER_CONN_DOWN;
wake_up_interruptible(&ib_conn->wait);
}
}
Index: iser_initiator.c
===================================================================
--- iser_initiator.c (revision 6900)
+++ iser_initiator.c (revision 6924)
@@ -370,7 +370,7 @@ int iser_send_command(struct iscsi_conn
struct iscsi_cmd *hdr = ctask->hdr;
struct scsi_cmnd *sc = ctask->sc;
- if (atomic_read(&iser_conn->ib_conn->state) != ISER_CONN_UP) {
+ if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
return -EPERM;
}
@@ -454,7 +454,7 @@ int iser_send_data_out(struct iscsi_conn
unsigned int itt;
int err = 0;
- if (atomic_read(&iser_conn->ib_conn->state) != ISER_CONN_UP) {
+ if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
return -EPERM;
}
@@ -528,7 +528,7 @@ int iser_send_control(struct iscsi_conn
struct iser_regd_buf *regd_buf;
struct iser_device *device;
- if (atomic_read(&iser_conn->ib_conn->state) != ISER_CONN_UP) {
+ if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
return -EPERM;
}
Index: iscsi_iser.c
===================================================================
--- iscsi_iser.c (revision 6900)
+++ iscsi_iser.c (revision 6924)
@@ -649,13 +649,13 @@ iscsi_iser_ep_poll(__u64 ep_handle, int
return -EINVAL;
rc = wait_event_interruptible_timeout(ib_conn->wait,
- atomic_read(&ib_conn->state) == ISER_CONN_UP,
+ ib_conn->state == ISER_CONN_UP,
msecs_to_jiffies(timeout_ms));
/* if conn establishment failed, return error code to iscsi */
if (!rc &&
- (atomic_read(&ib_conn->state) == ISER_CONN_TERMINATING ||
- atomic_read(&ib_conn->state) == ISER_CONN_DOWN))
+ (ib_conn->state == ISER_CONN_TERMINATING ||
+ ib_conn->state == ISER_CONN_DOWN))
rc = -1;
iser_err("ib conn %p rc = %d\n", ib_conn, rc);
@@ -676,12 +676,9 @@ iscsi_iser_ep_disconnect(__u64 ep_handle
if (!ib_conn)
return;
- iser_err("ib conn %p state %d\n",ib_conn, atomic_read(&ib_conn->state));
+ iser_err("ib conn %p state %d\n",ib_conn, ib_conn->state);
- if (atomic_read(&ib_conn->state) == ISER_CONN_UP)
- iser_conn_terminate(ib_conn);
- else
- iser_conn_release(ib_conn);
+ iser_conn_terminate(ib_conn);
}
static struct scsi_host_template iscsi_iser_sht = {
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