5 files changed, 23 insertions, 29 deletions

diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index 0dc800b5a4ea..a3c2aab53de8 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -328,7 +328,8 @@ static int efx_poll(struct napi_struct *napi, int budget)
  * processing to finish, then directly poll (and ack ) the eventq.
  * Finally reenable NAPI and interrupts.
  *
- * Since we are touching interrupts the caller should hold the suspend lock
+ * This is for use only during a loopback self-test.  It must not
+ * deliver any packets up the stack as this can result in deadlock.
  */
 void efx_process_channel_now(struct efx_channel *channel)
 {
@@ -336,6 +337,7 @@ void efx_process_channel_now(struct efx_channel *channel)
 
         BUG_ON(channel->channel >= efx->n_channels);
         BUG_ON(!channel->enabled);
+        BUG_ON(!efx->loopback_selftest);
 
         /* Disable interrupts and wait for ISRs to complete */
         efx_nic_disable_interrupts(efx);
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index 9ffa9a6b55a0..191a311da2dc 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -330,7 +330,6 @@ enum efx_rx_alloc_method {
  * @eventq_mask: Event queue pointer mask
  * @eventq_read_ptr: Event queue read pointer
  * @last_eventq_read_ptr: Last event queue read pointer value.
- * @magic_count: Event queue test event count
  * @irq_count: Number of IRQs since last adaptive moderation decision
  * @irq_mod_score: IRQ moderation score
  * @rx_alloc_level: Watermark based heuristic counter for pushing descriptors
@@ -360,7 +359,6 @@ struct efx_channel {
         unsigned int eventq_mask;
         unsigned int eventq_read_ptr;
         unsigned int last_eventq_read_ptr;
-        unsigned int magic_count;
 
         unsigned int irq_count;
         unsigned int irq_mod_score;
diff --git a/drivers/net/sfc/nic.c b/drivers/net/sfc/nic.c
index e8396614daf3..10f1cb79c147 100644
--- a/drivers/net/sfc/nic.c
+++ b/drivers/net/sfc/nic.c
@@ -84,7 +84,8 @@ static inline void efx_write_buf_tbl(struct efx_nic *efx, efx_qword_t *value,
 static inline efx_qword_t *efx_event(struct efx_channel *channel,
                                      unsigned int index)
 {
-        return ((efx_qword_t *) (channel->eventq.addr)) + index;
+        return ((efx_qword_t *) (channel->eventq.addr)) +
+                (index & channel->eventq_mask);
 }
 
 /* See if an event is present
@@ -673,7 +674,8 @@ void efx_nic_eventq_read_ack(struct efx_channel *channel)
         efx_dword_t reg;
         struct efx_nic *efx = channel->efx;
 
-        EFX_POPULATE_DWORD_1(reg, FRF_AZ_EVQ_RPTR, channel->eventq_read_ptr);
+        EFX_POPULATE_DWORD_1(reg, FRF_AZ_EVQ_RPTR,
+                             channel->eventq_read_ptr & channel->eventq_mask);
         efx_writed_table(efx, &reg, efx->type->evq_rptr_tbl_base,
                          channel->channel);
 }
@@ -908,7 +910,7 @@ efx_handle_generated_event(struct efx_channel *channel, efx_qword_t *event)
 
         code = EFX_QWORD_FIELD(*event, FSF_AZ_DRV_GEN_EV_MAGIC);
         if (code == EFX_CHANNEL_MAGIC_TEST(channel))
-                ++channel->magic_count;
+                ; /* ignore */
         else if (code == EFX_CHANNEL_MAGIC_FILL(channel))
                 /* The queue must be empty, so we won't receive any rx
                  * events, so efx_process_channel() won't refill the
@@ -1015,8 +1017,7 @@ int efx_nic_process_eventq(struct efx_channel *channel, int budget)
                 /* Clear this event by marking it all ones */
                 EFX_SET_QWORD(*p_event);
 
-                /* Increment read pointer */
-                read_ptr = (read_ptr + 1) & channel->eventq_mask;
+                ++read_ptr;
 
                 ev_code = EFX_QWORD_FIELD(event, FSF_AZ_EV_CODE);
 
@@ -1060,6 +1061,13 @@ out:
         return spent;
 }
 
+/* Check whether an event is present in the eventq at the current
+ * read pointer.  Only useful for self-test.
+ */
+bool efx_nic_event_present(struct efx_channel *channel)
+{
+        return efx_event_present(efx_event(channel, channel->eventq_read_ptr));
+}
 
 /* Allocate buffer table entries for event queue */
 int efx_nic_probe_eventq(struct efx_channel *channel)
@@ -1165,7 +1173,7 @@ static void efx_poll_flush_events(struct efx_nic *efx)
         struct efx_tx_queue *tx_queue;
         struct efx_rx_queue *rx_queue;
         unsigned int read_ptr = channel->eventq_read_ptr;
-        unsigned int end_ptr = (read_ptr - 1) & channel->eventq_mask;
+        unsigned int end_ptr = read_ptr + channel->eventq_mask - 1;
 
         do {
                 efx_qword_t *event = efx_event(channel, read_ptr);
@@ -1205,7 +1213,7 @@ static void efx_poll_flush_events(struct efx_nic *efx)
                  * it's ok to throw away every non-flush event */
                 EFX_SET_QWORD(*event);
 
-                read_ptr = (read_ptr + 1) & channel->eventq_mask;
+                ++read_ptr;
         } while (read_ptr != end_ptr);
 
         channel->eventq_read_ptr = read_ptr;
diff --git a/drivers/net/sfc/nic.h b/drivers/net/sfc/nic.h
index d9de1b647d41..a42db6e35be3 100644
--- a/drivers/net/sfc/nic.h
+++ b/drivers/net/sfc/nic.h
@@ -184,6 +184,7 @@ extern void efx_nic_fini_eventq(struct efx_channel *channel);
 extern void efx_nic_remove_eventq(struct efx_channel *channel);
 extern int efx_nic_process_eventq(struct efx_channel *channel, int rx_quota);
 extern void efx_nic_eventq_read_ack(struct efx_channel *channel);
+extern bool efx_nic_event_present(struct efx_channel *channel);
 
 /* MAC/PHY */
 extern void falcon_drain_tx_fifo(struct efx_nic *efx);
diff --git a/drivers/net/sfc/selftest.c b/drivers/net/sfc/selftest.c
index 845808408924..50ad3bcaf68a 100644
--- a/drivers/net/sfc/selftest.c
+++ b/drivers/net/sfc/selftest.c
@@ -131,8 +131,6 @@ static int efx_test_chip(struct efx_nic *efx, struct efx_self_tests *tests)
 static int efx_test_interrupts(struct efx_nic *efx,
                                struct efx_self_tests *tests)
 {
-        struct efx_channel *channel;
-
         netif_dbg(efx, drv, efx->net_dev, "testing interrupts\n");
         tests->interrupt = -1;
 
@@ -140,15 +138,6 @@ static int efx_test_interrupts(struct efx_nic *efx,
         efx->last_irq_cpu = -1;
         smp_wmb();
 
-        /* ACK each interrupting event queue. Receiving an interrupt due to
-         * traffic before a test event is raised is considered a pass */
-        efx_for_each_channel(channel, efx) {
-                if (channel->work_pending)
-                        efx_process_channel_now(channel);
-                if (efx->last_irq_cpu >= 0)
-                        goto success;
-        }
-
         efx_nic_generate_interrupt(efx);
 
         /* Wait for arrival of test interrupt. */
@@ -173,13 +162,13 @@ static int efx_test_eventq_irq(struct efx_channel *channel,
                                struct efx_self_tests *tests)
 {
         struct efx_nic *efx = channel->efx;
-        unsigned int magic_count, count;
+        unsigned int read_ptr, count;
 
         tests->eventq_dma[channel->channel] = -1;
         tests->eventq_int[channel->channel] = -1;
         tests->eventq_poll[channel->channel] = -1;
 
-        magic_count = channel->magic_count;
+        read_ptr = channel->eventq_read_ptr;
         channel->efx->last_irq_cpu = -1;
         smp_wmb();
 
@@ -190,10 +179,7 @@ static int efx_test_eventq_irq(struct efx_channel *channel,
         do {
                 schedule_timeout_uninterruptible(HZ / 100);
 
-                if (channel->work_pending)
-                        efx_process_channel_now(channel);
-
-                if (channel->magic_count != magic_count)
+                if (ACCESS_ONCE(channel->eventq_read_ptr) != read_ptr)
                         goto eventq_ok;
         } while (++count < 2);
 
@@ -211,8 +197,7 @@ static int efx_test_eventq_irq(struct efx_channel *channel,
         }
 
         /* Check to see if event was received even if interrupt wasn't */
-        efx_process_channel_now(channel);
-        if (channel->magic_count != magic_count) {
+        if (efx_nic_event_present(channel)) {
                 netif_err(efx, drv, efx->net_dev,
                           "channel %d event was generated, but "
                           "failed to trigger an interrupt\n", channel->channel);