Piteball/android_kernel_google_msm
1
0
Fork 0
mirror of https://github.com/followmsi/android_kernel_google_msm.git synced 2024-11-06 23:17:41 +00:00
Code Issues Projects Releases Wiki Activity

tty: n_smux: Fix packet close synchronization issue

Browse source 
If a channel is logical channel open or close ack is pending in the
transmit queue when a logical channel is closed, then they are currently
purged and the remote and local channel states are mismatched and the
port cannot be re-opened.  Note that this issue only occurs during rapid
open/close/open sequences that are typically only seen in remote
loopback stress testing.

Add code to not purge ACK commands from a logical channel unless the
logical channel purge is due to a subsystem restart (at which point the
remote state is known to be power-on default).

Change-Id: I52763323642bb7c505630bb994ecc1e021270d17
Signed-off-by: Eric Holmberg <eholmber@codeaurora.org>
(cherry picked from commit 0e91408cb6343d5ac18206ff3d6639ccec5464fd)
(cherry picked from commit ef0445e15b20369c7189a61d63fb284c5a51c3fb)
This commit is contained in:
Eric Holmberg 2012-07-11 11:46:28 -06:00 committed by Stephen Boyd
parent 840782ad43
commit 807fc66ba9
1 changed files with 27 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

40
drivers/tty/n_smux.c
View file

@ -351,7 +351,7 @@ static void list_channel(struct smux_lch_t *ch);
static int smux_send_status_cmd(struct smux_lch_t *ch);
static int smux_dispatch_rx_pkt(struct smux_pkt_t *pkt);
static void smux_flush_tty(void);
static void smux_purge_ch_tx_queue(struct smux_lch_t *ch);
static void smux_purge_ch_tx_queue(struct smux_lch_t *ch, int is_ssr);
static int schedule_notify(uint8_t lcid, int event,
const union notifier_metadata *metadata);
static int ssr_notifier_cb(struct notifier_block *this,
@ -503,7 +503,7 @@ static void smux_lch_purge(void)
/* Purge TX queue */
spin_lock(&ch->tx_lock_lhb2);
smux_purge_ch_tx_queue(ch);
smux_purge_ch_tx_queue(ch, 1);
spin_unlock(&ch->tx_lock_lhb2);
/* Notify user of disconnect and reset channel state */
@ -2158,25 +2158,35 @@ static void smux_flush_tty(void)
* Purge TX queue for logical channel.
*
* @ch Logical channel pointer
* @is_ssr 1 = this is a subsystem restart purge
*
* Must be called with the following spinlocks locked:
* state_lock_lhb1
* tx_lock_lhb2
*/
static void smux_purge_ch_tx_queue(struct smux_lch_t *ch)
static void smux_purge_ch_tx_queue(struct smux_lch_t *ch, int is_ssr)
{
struct smux_pkt_t *pkt;
int send_disconnect = 0;
struct smux_pkt_t *pkt_tmp;
int is_state_pkt;
while (!list_empty(&ch->tx_queue)) {
pkt = list_first_entry(&ch->tx_queue, struct smux_pkt_t,
list);
list_del(&pkt->list);
list_for_each_entry_safe(pkt, pkt_tmp, &ch->tx_queue, list) {
is_state_pkt = 0;
if (pkt->hdr.cmd == SMUX_CMD_OPEN_LCH) {
/* Open was never sent, just force to closed state */
ch->local_state = SMUX_LCH_LOCAL_CLOSED;
send_disconnect = 1;
if (pkt->hdr.flags & SMUX_CMD_OPEN_ACK) {
/* Open ACK must still be sent */
is_state_pkt = 1;
} else {
/* Open never sent -- force to closed state */
ch->local_state = SMUX_LCH_LOCAL_CLOSED;
send_disconnect = 1;
}
} else if (pkt->hdr.cmd == SMUX_CMD_CLOSE_LCH) {
if (pkt->hdr.flags & SMUX_CMD_CLOSE_ACK)
is_state_pkt = 1;
if (!send_disconnect)
is_state_pkt = 1;
} else if (pkt->hdr.cmd == SMUX_CMD_DATA) {
/* Notify client of failed write */
union notifier_metadata meta_write;
@ -2186,7 +2196,11 @@ static void smux_purge_ch_tx_queue(struct smux_lch_t *ch)
meta_write.write.len = pkt->hdr.payload_len;
schedule_notify(ch->lcid, SMUX_WRITE_FAIL, &meta_write);
}
smux_free_pkt(pkt);
if (!is_state_pkt || is_ssr) {
list_del(&pkt->list);
smux_free_pkt(pkt);
}
}
if (send_disconnect) {
@ -3020,7 +3034,7 @@ int msm_smux_close(uint8_t lcid)
/* Purge TX queue */
spin_lock(&ch->tx_lock_lhb2);
smux_purge_ch_tx_queue(ch);
smux_purge_ch_tx_queue(ch, 0);
spin_unlock(&ch->tx_lock_lhb2);
/* Send Close Command */