tty: n_smux: add separate close notifications
When an SMUX port state is closed, the close request is sent to the
remote system. The port cannot be re-opened until the remote system
acknowledges the close request. If the client attempts to re-open the
port during this time, then the -EAGAIN error code is returned and the
client must keep retrying to open the port. An event-driven approach
would be better, but the client does not receive local state
notifications, so this is not possible.
Add local and remote closed notifications so clients can handle the
closing state transitions without using polling.
CRs-Fixed: 510114
Change-Id: I48008804d23dbfd05df0becd4bc1c695e599a835
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
diff --git a/drivers/tty/n_smux.c b/drivers/tty/n_smux.c
index 3794aa9..c8e5163 100644
--- a/drivers/tty/n_smux.c
+++ b/drivers/tty/n_smux.c
@@ -297,6 +297,8 @@
[SMUX_HIGH_WM_HIT] = "HIGH_WM_HIT",
[SMUX_RX_RETRY_HIGH_WM_HIT] = "RX_RETRY_HIGH_WM_HIT",
[SMUX_RX_RETRY_LOW_WM_HIT] = "RX_RETRY_LOW_WM_HIT",
+ [SMUX_LOCAL_CLOSED] = "LOCAL_CLOSED",
+ [SMUX_REMOTE_CLOSED] = "REMOTE_CLOSED",
};
static const char * const smux_local_state[] = {
@@ -553,6 +555,8 @@
/* Close all ports */
for (i = 0 ; i < SMUX_NUM_LOGICAL_CHANNELS; i++) {
+ union notifier_metadata meta;
+ int send_disconnect = 0;
ch = &smux_lch[i];
SMUX_DBG("smux: %s: cleaning up lcid %d\n", __func__, i);
@@ -563,14 +567,19 @@
smux_purge_ch_tx_queue(ch, 1);
spin_unlock(&ch->tx_lock_lhb2);
+ meta.disconnected.is_ssr = smux.in_reset;
/* Notify user of disconnect and reset channel state */
if (ch->local_state == SMUX_LCH_LOCAL_OPENED ||
ch->local_state == SMUX_LCH_LOCAL_CLOSING) {
- union notifier_metadata meta;
-
- meta.disconnected.is_ssr = smux.in_reset;
- schedule_notify(ch->lcid, SMUX_DISCONNECTED, &meta);
+ schedule_notify(ch->lcid, SMUX_LOCAL_CLOSED, &meta);
+ send_disconnect = 1;
}
+ if (ch->remote_state != SMUX_LCH_REMOTE_CLOSED) {
+ schedule_notify(ch->lcid, SMUX_REMOTE_CLOSED, &meta);
+ send_disconnect = 1;
+ }
+ if (send_disconnect)
+ schedule_notify(ch->lcid, SMUX_DISCONNECTED, &meta);
ch->local_state = SMUX_LCH_LOCAL_CLOSED;
ch->remote_state = SMUX_LCH_REMOTE_CLOSED;
@@ -857,6 +866,10 @@
IPC_LOG_STR("smux: %s ch:%d\n", event_to_str(event), lcid);
ch = &smux_lch[lcid];
+ if (!ch->notify) {
+ SMUX_DBG("%s: [%d]lcid notify fn is NULL\n", __func__, lcid);
+ return ret;
+ }
notify_handle = kzalloc(sizeof(struct smux_notify_handle),
GFP_ATOMIC);
if (!notify_handle) {
@@ -1235,6 +1248,7 @@
SMUX_LCH_LOCAL_CLOSING,
SMUX_LCH_LOCAL_CLOSED);
ch->local_state = SMUX_LCH_LOCAL_CLOSED;
+ schedule_notify(lcid, SMUX_LOCAL_CLOSED, &meta_disconnected);
if (ch->remote_state == SMUX_LCH_REMOTE_CLOSED)
schedule_notify(lcid, SMUX_DISCONNECTED,
&meta_disconnected);
@@ -1422,6 +1436,7 @@
}
}
+ schedule_notify(lcid, SMUX_REMOTE_CLOSED, &meta_disconnected);
if (ch->local_state == SMUX_LCH_LOCAL_CLOSED)
schedule_notify(lcid, SMUX_DISCONNECTED,
&meta_disconnected);
@@ -2360,8 +2375,11 @@
union notifier_metadata meta_disconnected;
meta_disconnected.disconnected.is_ssr = smux.in_reset;
- schedule_notify(ch->lcid, SMUX_DISCONNECTED,
+ schedule_notify(ch->lcid, SMUX_LOCAL_CLOSED,
&meta_disconnected);
+ if (ch->remote_state == SMUX_LCH_REMOTE_CLOSED)
+ schedule_notify(ch->lcid, SMUX_DISCONNECTED,
+ &meta_disconnected);
}
}
@@ -3089,11 +3107,15 @@
*
* @returns 0 for success, <0 otherwise
*
- * A channel must be fully closed (either not previously opened or
- * msm_smux_close() has been called and the SMUX_DISCONNECTED has been
- * received.
+ * The local channel state must be closed (either not previously
+ * opened or msm_smux_close() has been called and the SMUX_LOCAL_CLOSED
+ * notification has been received).
*
- * One the remote side is opened, the client will receive a SMUX_CONNECTED
+ * If open is called before the SMUX_LOCAL_CLOSED has been received,
+ * then the function will return -EAGAIN and the client will need to
+ * retry the open later.
+ *
+ * Once the remote side is opened, the client will receive a SMUX_CONNECTED
* event.
*/
int msm_smux_open(uint8_t lcid, void *priv,
@@ -3170,7 +3192,8 @@
* @returns 0 for success, <0 otherwise
*
* Once the close event has been acknowledge by the remote side, the client
- * will receive a SMUX_DISCONNECTED notification.
+ * will receive an SMUX_LOCAL_CLOSED notification. If the remote side is also
+ * closed, then an SMUX_DISCONNECTED notification will also be sent.
*/
int msm_smux_close(uint8_t lcid)
{