| Message ID | 20230601211507.707619-6-jacob.e.keller@intel.com |
|---|---|
| State | Accepted |
| Delegated to: | Anthony Nguyen |
| Headers | show |
| Series | ice: Improve miscellaneous interrupt code | expand |
> -----Original Message----- > From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of Jacob Keller > Sent: Friday, June 2, 2023 2:45 AM > To: Intel Wired LAN <intel-wired-lan@lists.osuosl.org>; Nguyen, Anthony L <anthony.l.nguyen@intel.com> > Subject: [Intel-wired-lan] [PATCH iwl-next v3 5/5] ice: do not re-enable miscellaneous interrupt until thread_fn completes > > The ice driver uses threaded IRQ for managing Tx timestamps via the > devm_request_threaded_irq() interface. The ice_misc_intr() handler function is responsible for processing the hard interrupt context, and can wake the > ice_misc_intr_thread_fn() by returning IRQ_WAKE_THREAD. > > The request_threaded_irq() function comment says: > > @handler is still called in hard interrupt context and has to check > whether the interrupt originates from the device. If yes, it needs to > disable the interrupt on the device and return IRQ_WAKE_THREAD which will > wake up the handler thread and run the @thread_fn. > > We currently re-enable the Other Interrupt Cause Register (OCIR) at the end of ice_misc_intr(). In practice, this seems to be ok, but it can make communicating between the handler function and the thread > function difficult. This is because the interrupt can trigger again while the thread function is still processing. > > Move the OICR update to the end of the thread function, leaving the other interrupt cause disabled in hardware until we complete one pass of the thread function. This prevents the miscellaneous interrupt > from firing until after we finish the thread function. > > Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> > --- > drivers/net/ethernet/intel/ice/ice_main.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > Tested-by: Arpana Arland <arpanax.arland@intel.com> (A Contingent worker at Intel)
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c index 8f3ddc8451bd..6eae43828c46 100644 --- a/drivers/net/ethernet/intel/ice/ice_main.c +++ b/drivers/net/ethernet/intel/ice/ice_main.c @@ -3179,8 +3179,6 @@ static irqreturn_t ice_misc_intr(int __always_unused irq, void *data) } } - ice_irq_dynamic_ena(hw, NULL, NULL); - return IRQ_WAKE_THREAD; } @@ -3192,6 +3190,9 @@ static irqreturn_t ice_misc_intr(int __always_unused irq, void *data) static irqreturn_t ice_misc_intr_thread_fn(int __always_unused irq, void *data) { struct ice_pf *pf = data; + struct ice_hw *hw; + + hw = &pf->hw; if (ice_is_reset_in_progress(pf->state)) return IRQ_HANDLED; @@ -3202,8 +3203,6 @@ static irqreturn_t ice_misc_intr_thread_fn(int __always_unused irq, void *data) ice_ptp_extts_event(pf); if (test_and_clear_bit(ICE_MISC_THREAD_TX_TSTAMP, pf->misc_thread)) { - struct ice_hw *hw = &pf->hw; - /* Process outstanding Tx timestamps. If there is more work, * re-arm the interrupt to trigger again. */ @@ -3213,6 +3212,8 @@ static irqreturn_t ice_misc_intr_thread_fn(int __always_unused irq, void *data) } } + ice_irq_dynamic_ena(hw, NULL, NULL); + return IRQ_HANDLED; }
The ice driver uses threaded IRQ for managing Tx timestamps via the devm_request_threaded_irq() interface. The ice_misc_intr() handler function is responsible for processing the hard interrupt context, and can wake the ice_misc_intr_thread_fn() by returning IRQ_WAKE_THREAD. The request_threaded_irq() function comment says: @handler is still called in hard interrupt context and has to check whether the interrupt originates from the device. If yes, it needs to disable the interrupt on the device and return IRQ_WAKE_THREAD which will wake up the handler thread and run the @thread_fn. We currently re-enable the Other Interrupt Cause Register (OCIR) at the end of ice_misc_intr(). In practice, this seems to be ok, but it can make communicating between the handler function and the thread function difficult. This is because the interrupt can trigger again while the thread function is still processing. Move the OICR update to the end of the thread function, leaving the other interrupt cause disabled in hardware until we complete one pass of the thread function. This prevents the miscellaneous interrupt from firing until after we finish the thread function. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> --- drivers/net/ethernet/intel/ice/ice_main.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)