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drivers/net/telnet.c: I/O thread now offloads reading from socket from client thread to the I/O thread.

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This commit is contained in:
Valmantas Palikša 2019-05-22 07:46:40 -06:00 • committed by Gregory Nutt
parent 6312d49e25
commit 4e56c577fe
1 changed files with 54 additions and 34 deletions
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88
drivers/net/telnet.c
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@ -155,6 +155,7 @@ enum telnet_state_e
struct telnet_dev_s
{
sem_t td_exclsem; /* Enforces mutually exclusive access */
sem_t td_iosem; /* I/O thread will notify that data is available */
uint8_t td_state; /* (See telnet_state_e) */
uint8_t td_pending; /* Number of valid, pending bytes in the rxbuffer */
uint8_t td_offset; /* Offset to the valid, pending bytes in the rxbuffer */
@ -820,6 +821,8 @@ static int telnet_close(FAR struct file *filep)
}
}
/* If the socket is still polling */
if (priv->fds.events)
{
/* Tear down the poll */
@ -830,7 +833,7 @@ static int telnet_close(FAR struct file *filep)
nxsem_post(&g_clients_sem);
/* Notify the I/O thread */
/* Notify the I/O thread that a client was removed */
nxsem_post(&g_iosem);
@ -881,56 +884,50 @@ static ssize_t telnet_read(FAR struct file *filep, FAR char *buffer,
/* First, handle the case where there are still valid bytes left in the
* I/O buffer from the last time that read was called. NOTE: Much of
* what we read may be protocol stuff and may not correspond to user
* data. Hence we need the loop and we need may need to call psock_recv()
* data. Hence we need the loop and we need may need to wait for data
* multiple times in order to get data that the client is interested in.
*/
do
{
if (priv->td_pending > 0)
if (priv->td_pending == 0)
{
/* Process the buffered telnet data */
FAR const char *src = &priv->td_rxbuffer[priv->td_offset];
ret = telnet_receive(priv, src, priv->td_pending, buffer, len);
}
/* Read a buffer of data from the telnet client */
else
{
/* Test for non-blocking read */
if (filep->f_oflags & O_NONBLOCK)
{
return 0;
}
ret = psock_recv(&priv->td_psock, priv->td_rxbuffer,
CONFIG_TELNET_RXBUFFER_SIZE, 0);
/* Did we receive anything? */
if (ret > 0)
do
{
/* Yes.. Process the newly received telnet data */
/* Wait for new data (or error) */
telnet_dumpbuffer("Received buffer", priv->td_rxbuffer, ret);
ret = telnet_receive(priv, priv->td_rxbuffer, ret, buffer, len);
}
ret = nxsem_wait(&priv->td_iosem);
}
while (ret == -EINTR);
/* Otherwise the peer closed the connection (ret == 0) or an error
* occurred (ret < 0).
*/
/* poll fds.revents contains last poll status in case of error */
else
if ((priv->fds.revents & (POLLHUP | POLLERR)) != 0)
{
break;
return -EPIPE;
}
}
/* Take exclusive access to data buffer */
(void)nxsem_wait(&priv->td_exclsem);
/* Process the buffered telnet data */
FAR const char *src = &priv->td_rxbuffer[priv->td_offset];
ret = telnet_receive(priv, src, priv->td_pending, buffer, len);
nxsem_post(&priv->td_exclsem);
}
while (ret == 0);
return ret;
/* Returned Value:
*
* ret > 0: The number of characters copied into the user buffer by
@ -1053,6 +1050,13 @@ static int telnet_session(FAR struct telnet_session_s *session)
/* Initialize the allocated driver instance */
nxsem_init(&priv->td_exclsem, 0, 1);
nxsem_init(&priv->td_iosem, 0, 0);
/* td_iosem is used for signaling and, hence, must not participate in
* priority inheritance.
*/
sem_setprotocol(&priv->td_iosem, SEM_PRIO_NONE);
priv->td_state = STATE_NORMAL;
priv->td_crefs = 0;
@ -1162,7 +1166,7 @@ static int telnet_session(FAR struct telnet_session_s *session)
/* Start the I/O thread */
g_telnet_io_kthread =
kthread_create("telnet_io",CONFIG_TELNET_IOTHREAD_PRIORITY,
kthread_create("telnet_io", CONFIG_TELNET_IOTHREAD_PRIORITY,
CONFIG_TELNET_IOTHREAD_STACKSIZE, telnet_io_main, 0);
}
@ -1305,7 +1309,9 @@ static int telnet_io_main(int argc, FAR char** argv)
nxsem_post(&g_clients_sem);
/* Wait for any Telnet client to exit and close the Telenet driver. */
/* Wait for any Telnet connect/disconnect events to
* to include/remove client sockets from polling
*/
(void)nxsem_wait(&g_iosem);
@ -1323,6 +1329,9 @@ static int telnet_io_main(int argc, FAR char** argv)
{
if (priv->td_pending < CONFIG_TELNET_RXBUFFER_SIZE)
{
/* Take exclusive access to data buffer */
nxsem_wait(&priv->td_exclsem);
buffer = priv->td_rxbuffer + priv->td_pending +
priv->td_offset;
@ -1332,6 +1341,11 @@ static int telnet_io_main(int argc, FAR char** argv)
0);
priv->td_pending += ret;
nxsem_post(&priv->td_exclsem);
/* Notify the client thread that data is available */
nxsem_post(&priv->td_iosem);
#ifdef HAVE_SIGNALS
/* Check if any of the received characters is a
@ -1346,7 +1360,7 @@ static int telnet_io_main(int argc, FAR char** argv)
}
}
/* Check for driver events.. POLLHUP in particular */
/* If poll was setup previously (events != 0), tear it down */
if (priv->fds.events)
{
@ -1354,11 +1368,17 @@ static int telnet_io_main(int argc, FAR char** argv)
priv->fds.events = 0;
}
/* POLLHUP (or POLLERR) indicates that this session has terminated. */
/* POLLHUP (or POLLERR) indicates that this session has
* terminated.
*/
if (priv->fds.revents & (POLLHUP | POLLERR))
{
g_telnet_clients[i] = 0;
/* notify the client thread */
nxsem_post(&priv->td_iosem);
}
}
}