iwlwifi: use threaded interrupt handler
With new transports coming up, move to threaded
interrupt handling now. This has the advantage
that we can use the same locking scheme with all
different transports we may need to implement.
Note that the TX path obviously still runs in a
tasklet, so some spin_lock() calls need to change
to spin_lock_bh() calls to properly lock out the
TX path.
In my test on a Calpella platform this has no
impact on throughput or latency.
Also add lockdep annotations to avoid lockups due
to catch sending synchronous commands or using
locks that connect with them from the irq thread.
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/pcie/rx.c b/drivers/net/wireless/iwlwifi/pcie/rx.c
index a9ca1d3..b0ae06d 100644
--- a/drivers/net/wireless/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/rx.c
@@ -81,10 +81,10 @@
* 'processed' and 'read' driver indexes as well)
* + A received packet is processed and handed to the kernel network stack,
* detached from the iwl->rxq. The driver 'processed' index is updated.
- * + The Host/Firmware iwl->rxq is replenished at tasklet time from the rx_free
- * list. If there are no allocated buffers in iwl->rxq->rx_free, the READ
- * INDEX is not incremented and iwl->status(RX_STALLED) is set. If there
- * were enough free buffers and RX_STALLED is set it is cleared.
+ * + The Host/Firmware iwl->rxq is replenished at irq thread time from the
+ * rx_free list. If there are no allocated buffers in iwl->rxq->rx_free,
+ * the READ INDEX is not incremented and iwl->status(RX_STALLED) is set.
+ * If there were enough free buffers and RX_STALLED is set it is cleared.
*
*
* Driver sequence:
@@ -214,9 +214,9 @@
/*
* If the device isn't enabled - not need to try to add buffers...
* This can happen when we stop the device and still have an interrupt
- * pending. We stop the APM before we sync the interrupts / tasklets
- * because we have to (see comment there). On the other hand, since
- * the APM is stopped, we cannot access the HW (in particular not prph).
+ * pending. We stop the APM before we sync the interrupts because we
+ * have to (see comment there). On the other hand, since the APM is
+ * stopped, we cannot access the HW (in particular not prph).
* So don't try to restock if the APM has been already stopped.
*/
if (!test_bit(STATUS_DEVICE_ENABLED, &trans_pcie->status))
@@ -796,11 +796,14 @@
clear_bit(STATUS_HCMD_ACTIVE, &trans_pcie->status);
wake_up(&trans_pcie->wait_command_queue);
+ local_bh_disable();
iwl_op_mode_nic_error(trans->op_mode);
+ local_bh_enable();
}
-void iwl_pcie_tasklet(struct iwl_trans *trans)
+irqreturn_t iwl_pcie_irq_handler(int irq, void *dev_id)
{
+ struct iwl_trans *trans = dev_id;
struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
struct isr_statistics *isr_stats = &trans_pcie->isr_stats;
u32 inta = 0;
@@ -811,6 +814,8 @@
u32 inta_mask;
#endif
+ lock_map_acquire(&trans->sync_cmd_lockdep_map);
+
spin_lock_irqsave(&trans_pcie->irq_lock, flags);
/* Ack/clear/reset pending uCode interrupts.
@@ -855,7 +860,7 @@
handled |= CSR_INT_BIT_HW_ERR;
- return;
+ goto out;
}
#ifdef CONFIG_IWLWIFI_DEBUG
@@ -1005,6 +1010,10 @@
/* Re-enable RF_KILL if it occurred */
else if (handled & CSR_INT_BIT_RF_KILL)
iwl_enable_rfkill_int(trans);
+
+out:
+ lock_map_release(&trans->sync_cmd_lockdep_map);
+ return IRQ_HANDLED;
}
/******************************************************************************
@@ -1127,7 +1136,7 @@
/* Disable (but don't clear!) interrupts here to avoid
* back-to-back ISRs and sporadic interrupts from our NIC.
- * If we have something to service, the tasklet will re-enable ints.
+ * If we have something to service, the irq thread will re-enable ints.
* If we *don't* have something, we'll re-enable before leaving here. */
inta_mask = iwl_read32(trans, CSR_INT_MASK);
iwl_write32(trans, CSR_INT_MASK, 0x00000000);
@@ -1167,9 +1176,9 @@
#endif
trans_pcie->inta |= inta;
- /* iwl_pcie_tasklet() will service interrupts and re-enable them */
+ /* the thread will service interrupts and re-enable them */
if (likely(inta))
- tasklet_schedule(&trans_pcie->irq_tasklet);
+ return IRQ_WAKE_THREAD;
else if (test_bit(STATUS_INT_ENABLED, &trans_pcie->status) &&
!trans_pcie->inta)
iwl_enable_interrupts(trans);
@@ -1277,9 +1286,10 @@
trans_pcie->inta |= inta;
/* iwl_pcie_tasklet() will service interrupts and re-enable them */
- if (likely(inta))
- tasklet_schedule(&trans_pcie->irq_tasklet);
- else if (test_bit(STATUS_INT_ENABLED, &trans_pcie->status) &&
+ if (likely(inta)) {
+ spin_unlock_irqrestore(&trans_pcie->irq_lock, flags);
+ return IRQ_WAKE_THREAD;
+ } else if (test_bit(STATUS_INT_ENABLED, &trans_pcie->status) &&
!trans_pcie->inta) {
/* Allow interrupt if was disabled by this handler and
* no tasklet was schedules, We should not enable interrupt,