net/drivers/skeleton.c: Back out serialization changes of the last commit. They are not necessary in the skeleton.c example because the calls to net_lock() at the beginning of each worker function will enforce serialization.
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Gregory Nutt
parent
e2eb5f1ae0
commit
c976a66f8d
8
TODO
8
TODO
@ -1055,8 +1055,12 @@ o Network (net/, drivers/net)
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additional mechanism would have to be added to enforce that
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serialization.
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See nuttx/drivers/net/skeleton.c for an example of how
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serialization may be added to an Ethernet driver.
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NOTE: Most drivers will call net_lock() and net_unlock() around
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the critical portions of the driver work. In that case, all work
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will be properly serialized. This issue only applies to drivers
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that may perform operations that require protection outside of
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the net_lock'ed region. Sometimes, this may require extending
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the netlock() to be beginning of the driver work function.
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Status: Open
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Priority: High if you happen to be using Ethernet in this configuration.
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@ -43,7 +43,6 @@
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#include <stdint.h>
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#include <stdbool.h>
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#include <time.h>
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#include <semaphore.h>
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#include <string.h>
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#include <errno.h>
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#include <assert.h>
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@ -65,34 +64,24 @@
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* If processing is not done at the interrupt level, then work queue support
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* is required.
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*/
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#undef ETH_SERIALIZATION
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#if !defined(CONFIG_SCHED_WORKQUEUE)
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# error Work queue support is required in this configuration (CONFIG_SCHED_WORKQUEUE)
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#else
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/* Use the low priority work queue if possible */
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/* Use the selected work queue */
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# if defined(CONFIG_skeleton_HPWORK)
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# define ETHWORK HPWORK
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# elif defined(CONFIG_skeleton_LPWORK)
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# define ETHWORK LPWORK
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/* Serialization may be required in the special case where there are
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* multiple low priority work queues.
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*/
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# if CONFIG_SCHED_LPNTHREADS > 1
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# define ETH_SERIALIZATION 1
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# endif
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# else
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# error Neither CONFIG_skeleton_HPWORK nor CONFIG_skeleton_LPWORK defined
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# endif
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#endif
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/* CONFIG_skeleton_NINTERFACES determines the number of physical interfaces
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@ -130,9 +119,6 @@ struct skel_driver_s
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WDOG_ID sk_txtimeout; /* TX timeout timer */
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struct work_s sk_irqwork; /* For deferring interupt work to the work queue */
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struct work_s sk_pollwork; /* For deferring poll work to the work queue */
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#ifdef ETH_SERIALIZATION
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sem_t sk_lock; /* Serialization semaphore */
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#endif
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/* This holds the information visible to the NuttX network */
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@ -162,17 +148,6 @@ static struct skel_driver_s g_skel[CONFIG_skeleton_NINTERFACES];
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* Private Function Prototypes
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****************************************************************************/
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#ifdef ETH_SERIALIZATION
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/* Serialization support */
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static void skel_lock(FAR struct skel_driver_s *priv);
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# define skel_unlock(p) (void)sem_post(&(p)->sk_lock)
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#else
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# define skel_lock(p)
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# define skel_unlock(p)
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#endif
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/* Common TX logic */
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static int skel_transmit(FAR struct skel_driver_s *priv);
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@ -216,36 +191,6 @@ static void skel_ipv6multicast(FAR struct skel_driver_s *priv);
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Function: skel_lock
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*
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* Description:
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* When there are multiple LP work queues, we must force serialization of
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* work.
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*
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* Parameters:
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* priv - Reference to the driver state structure
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*
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* Returned Value:
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* None
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*
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* Assumptions:
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* Called in the context of thread of the LP work queue.
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*
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****************************************************************************/
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#ifdef ETH_SERIALIZATION
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static void skel_lock(FAR struct skel_driver_s *priv)
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{
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while (sem_wait(&priv->sk_lock) < 0)
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{
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/* EINTR is the only expected error value */
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DEBUGASSERT(errno == EINTR);
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}
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}
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#endif
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/****************************************************************************
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* Function: skel_transmit
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*
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@ -562,7 +507,13 @@ static void skel_interrupt_work(FAR void *arg)
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{
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FAR struct skel_driver_s *priv = (FAR struct skel_driver_s *)arg;
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skel_lock(priv);
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/* Lock the network and serialize driver operations if necessary.
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* NOTE: Serialization is only required in the case where the driver work
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* is performed on an LP worker thread and where more than one LP worker
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* thread has been configured.
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*/
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net_lock();
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/* Process pending Ethernet interrupts */
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@ -572,7 +523,6 @@ static void skel_interrupt_work(FAR void *arg)
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/* Check if we received an incoming packet, if so, call skel_receive() */
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net_lock();
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skel_receive(priv);
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/* Check if a packet transmission just completed. If so, call skel_txdone.
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@ -586,7 +536,6 @@ static void skel_interrupt_work(FAR void *arg)
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/* Re-enable Ethernet interrupts */
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up_enable_irq(CONFIG_skeleton_IRQ);
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skel_unlock(priv);
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}
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/****************************************************************************
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@ -655,7 +604,13 @@ static void skel_txtimeout_work(FAR void *arg)
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{
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FAR struct skel_driver_s *priv = (FAR struct skel_driver_s *)arg;
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skel_lock(priv);
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/* Lock the network and serialize driver operations if necessary.
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* NOTE: Serialization is only required in the case where the driver work
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* is performed on an LP worker thread and where more than one LP worker
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* thread has been configured.
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*/
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net_lock();
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/* Increment statistics and dump debug info */
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@ -665,11 +620,8 @@ static void skel_txtimeout_work(FAR void *arg)
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/* Then poll the network for new XMIT data */
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net_lock();
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(void)devif_poll(&priv->sk_dev, skel_txpoll);
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net_unlock();
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skel_unlock(priv);
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}
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/****************************************************************************
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@ -749,7 +701,13 @@ static void skel_poll_work(FAR void *arg)
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{
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FAR struct skel_driver_s *priv = (FAR struct skel_driver_s *)arg;
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skel_lock(priv);
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/* Lock the network and serialize driver operations if necessary.
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* NOTE: Serialization is only required in the case where the driver work
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* is performed on an LP worker thread and where more than one LP worker
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* thread has been configured.
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*/
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net_lock();
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/* Perform the poll */
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@ -762,7 +720,6 @@ static void skel_poll_work(FAR void *arg)
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* progress, we will missing TCP time state updates?
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*/
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net_lock();
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(void)devif_timer(&priv->sk_dev, skel_txpoll);
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/* Setup the watchdog poll timer again */
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@ -770,8 +727,6 @@ static void skel_poll_work(FAR void *arg)
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(void)wd_start(priv->sk_txpoll, skeleton_WDDELAY, skel_poll_expiry, 1,
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(wdparm_t)priv);
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net_unlock();
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skel_unlock(priv);
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}
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/****************************************************************************
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@ -920,11 +875,16 @@ static void skel_txavail_work(FAR void *arg)
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{
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FAR struct skel_driver_s *priv = (FAR struct skel_driver_s *)arg;
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skel_lock(priv);
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/* Lock the network and serialize driver operations if necessary.
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* NOTE: Serialization is only required in the case where the driver work
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* is performed on an LP worker thread and where more than one LP worker
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* thread has been configured.
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*/
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net_lock();
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/* Ignore the notification if the interface is not yet up */
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net_lock();
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if (priv->sk_bifup)
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{
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/* Check if there is room in the hardware to hold another outgoing packet. */
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@ -935,7 +895,6 @@ static void skel_txavail_work(FAR void *arg)
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}
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net_unlock();
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skel_unlock(priv);
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}
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/****************************************************************************
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@ -1095,6 +1054,7 @@ static void skel_ipv6multicast(FAR struct skel_driver_s *priv)
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(void)skel_addmac(dev, g_ipv6_ethallnodes.ether_addr_octet);
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#endif /* CONFIG_NET_ICMPv6_AUTOCONF */
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#ifdef CONFIG_NET_ICMPv6_ROUTER
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/* Add the IPv6 all link-local routers Ethernet address. This is the
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* address that we expect to receive ICMPv6 Router Solicitation
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@ -1163,14 +1123,10 @@ int skel_initialize(int intf)
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/* Create a watchdog for timing polling for and timing of transmisstions */
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priv->sk_txpoll = wd_create(); /* Create periodic poll timer */
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priv->sk_txtimeout = wd_create(); /* Create TX timeout timer */
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priv->sk_txpoll = wd_create(); /* Create periodic poll timer */
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priv->sk_txtimeout = wd_create(); /* Create TX timeout timer */
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#ifdef ETH_SERIALIZATION
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/* Initialize the serialization semaphore */
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sem_init(&priv->sk_lock, 0, 1);
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#endif
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DEBUGASSERT(priv->sk_txpoll != NULL && priv->sk_txtimeout != NULL);
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/* Put the interface in the down state. This usually amounts to resetting
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* the device and/or calling skel_ifdown().
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@ -1223,14 +1223,14 @@ config SCHED_LPNTHREADS
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Such behavior is necessary to support asynchronous I/O, AIO (for
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example).
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CAUTION: Some drivers, such as most Ethernet drivers, use the work
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queue to serialize network operations. The will also use the low-
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priority work queue if it is available. If there are multiple low-
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priority worker thread, then this can result in the loss of that
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serialization. There may be concurrent Ethernet operations running
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on different LP threads and this could lead to a failure. You may
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need to visit the use of the LP work queue on your configuration
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is you select CONFIG_SCHED_LPNTHREADS > 1
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CAUTION: Some drivers may use the work queue to serialize
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operations. The may also use the low-priority work queue if it is
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available. If there are multiple low-priority worker thread, then
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this can result in the loss of that serialization. There may be
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concurrent driver operations running on different LP threads and
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this could lead to a failure. You may need to visit the use of the
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LP work queue on your configuration is you select
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CONFIG_SCHED_LPNTHREADS > 1
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config SCHED_LPWORKPRIORITY
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int "Low priority worker thread priority"
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