sfc: Change priority and flags for automatic MAC filters

MAC filters inserted automatically by the driver, based on the device
address list (EF10) or no-match filters (Siena), should be overridable
at MANUAL or REQUIRED priority.  Currently they themselves have
REQUIRED priority and this requires some odd special-casing.

We also can't reliably tell whether such a MAC filter has or has
not been overridden.  We just remember that it is wanted by the
stack (RX_STACK flag).

Add another priority level, AUTO, between HINT and MANUAL, and
use this for the automatic filters while they have not been
overridden.  Remove the RX_STACK flag.  Add an RX_OVER_AUTO
flag which is set only when an AUTO filter has been overridden
(or was requested to be inserted while a higher-priority filter
existed).

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

4 files changed, 67 insertions, 54 deletions

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index 137c46b4b405..e5eeac9063d2 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -2341,10 +2341,7 @@ static s32 efx_ef10_filter_insert(struct efx_nic *efx,
 				    EFX_EF10_FILTER_FLAG_BUSY)
 					break;
 				if (spec->priority < saved_spec->priority &&
-				    !(saved_spec->priority ==
-				      EFX_FILTER_PRI_REQUIRED &&
-				      saved_spec->flags &
-				      EFX_FILTER_FLAG_RX_STACK)) {
+				    spec->priority != EFX_FILTER_PRI_AUTO) {
 					rc = -EPERM;
 					goto out_unlock;
 				}
@@ -2398,9 +2395,11 @@ found:
 	 */
 	saved_spec = efx_ef10_filter_entry_spec(table, ins_index);
 	if (saved_spec) {
-		if (spec->flags & EFX_FILTER_FLAG_RX_STACK) {
+		if (spec->priority == EFX_FILTER_PRI_AUTO &&
+		    saved_spec->priority >= EFX_FILTER_PRI_AUTO) {
 			/* Just make sure it won't be removed */
-			saved_spec->flags |= EFX_FILTER_FLAG_RX_STACK;
+			if (saved_spec->priority > EFX_FILTER_PRI_AUTO)
+				saved_spec->flags |= EFX_FILTER_FLAG_RX_OVER_AUTO;
 			table->entry[ins_index].spec &=
 				~EFX_EF10_FILTER_FLAG_STACK_OLD;
 			rc = ins_index;
@@ -2442,8 +2441,11 @@ found:
 	if (rc == 0) {
 		if (replacing) {
 			/* Update the fields that may differ */
+			if (saved_spec->priority == EFX_FILTER_PRI_AUTO)
+				saved_spec->flags |=
+					EFX_FILTER_FLAG_RX_OVER_AUTO;
 			saved_spec->priority = spec->priority;
-			saved_spec->flags &= EFX_FILTER_FLAG_RX_STACK;
+			saved_spec->flags &= EFX_FILTER_FLAG_RX_OVER_AUTO;
 			saved_spec->flags |= spec->flags;
 			saved_spec->rss_context = spec->rss_context;
 			saved_spec->dmaq_id = spec->dmaq_id;
@@ -2542,26 +2544,41 @@ static int efx_ef10_filter_remove_internal(struct efx_nic *efx,
 		spin_unlock_bh(&efx->filter_lock);
 		schedule();
 	}
+
 	spec = efx_ef10_filter_entry_spec(table, filter_idx);
-	if (!spec || spec->priority > priority ||
+	if (!spec ||
 	    (!stack_requested &&
 	     efx_ef10_filter_rx_match_pri(table, spec->match_flags) !=
 	     filter_id / HUNT_FILTER_TBL_ROWS)) {
 		rc = -ENOENT;
 		goto out_unlock;
 	}
+
+	if (spec->flags & EFX_FILTER_FLAG_RX_OVER_AUTO &&
+	    priority == EFX_FILTER_PRI_AUTO) {
+		/* Just remove flags */
+		spec->flags &= ~EFX_FILTER_FLAG_RX_OVER_AUTO;
+		table->entry[filter_idx].spec &= ~EFX_EF10_FILTER_FLAG_STACK_OLD;
+		rc = 0;
+		goto out_unlock;
+	}
+
+	if (spec->priority > priority) {
+		rc = -ENOENT;
+		goto out_unlock;
+	}
+
 	table->entry[filter_idx].spec |= EFX_EF10_FILTER_FLAG_BUSY;
 	spin_unlock_bh(&efx->filter_lock);
 
-	if (spec->flags & EFX_FILTER_FLAG_RX_STACK && !stack_requested) {
+	if (spec->flags & EFX_FILTER_FLAG_RX_OVER_AUTO) {
 		/* Reset steering of a stack-owned filter */
 
 		struct efx_filter_spec new_spec = *spec;
 
-		new_spec.priority = EFX_FILTER_PRI_REQUIRED;
+		new_spec.priority = EFX_FILTER_PRI_AUTO;
 		new_spec.flags = (EFX_FILTER_FLAG_RX |
-				  EFX_FILTER_FLAG_RX_RSS |
-				  EFX_FILTER_FLAG_RX_STACK);
+				  EFX_FILTER_FLAG_RX_RSS);
 		new_spec.dmaq_id = 0;
 		new_spec.rss_context = EFX_FILTER_RSS_CONTEXT_DEFAULT;
 		rc = efx_ef10_filter_push(efx, &new_spec,
@@ -2589,6 +2606,7 @@ static int efx_ef10_filter_remove_internal(struct efx_nic *efx,
 			efx_ef10_filter_set_entry(table, filter_idx, NULL, 0);
 		}
 	}
+
 	table->entry[filter_idx].spec &= ~EFX_EF10_FILTER_FLAG_BUSY;
 	wake_up_all(&table->waitq);
 out_unlock:
@@ -2731,8 +2749,6 @@ static s32 efx_ef10_filter_rfs_insert(struct efx_nic *efx,
 				rc = -EBUSY;
 				goto fail_unlock;
 			}
-			EFX_WARN_ON_PARANOID(saved_spec->flags &
-					     EFX_FILTER_FLAG_RX_STACK);
 			if (spec->priority < saved_spec->priority) {
 				rc = -EPERM;
 				goto fail_unlock;
@@ -3118,9 +3134,8 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic *efx)
 	/* Insert/renew unicast filters */
 	if (table->stack_uc_count >= 0) {
 		for (i = 0; i < table->stack_uc_count; i++) {
-			efx_filter_init_rx(&spec, EFX_FILTER_PRI_REQUIRED,
-					   EFX_FILTER_FLAG_RX_RSS |
-					   EFX_FILTER_FLAG_RX_STACK,
+			efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO,
+					   EFX_FILTER_FLAG_RX_RSS,
 					   0);
 			efx_filter_set_eth_local(&spec, EFX_FILTER_VID_UNSPEC,
 						 table->stack_uc_list[i].addr);
@@ -3129,7 +3144,7 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic *efx)
 				/* Fall back to unicast-promisc */
 				while (i--)
 					efx_ef10_filter_remove_safe(
-						efx, EFX_FILTER_PRI_REQUIRED,
+						efx, EFX_FILTER_PRI_AUTO,
 						table->stack_uc_list[i].id);
 				table->stack_uc_count = -1;
 				break;
@@ -3138,9 +3153,8 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic *efx)
 		}
 	}
 	if (table->stack_uc_count < 0) {
-		efx_filter_init_rx(&spec, EFX_FILTER_PRI_REQUIRED,
-				   EFX_FILTER_FLAG_RX_RSS |
-				   EFX_FILTER_FLAG_RX_STACK,
+		efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO,
+				   EFX_FILTER_FLAG_RX_RSS,
 				   0);
 		efx_filter_set_uc_def(&spec);
 		rc = efx_ef10_filter_insert(efx, &spec, true);
@@ -3155,9 +3169,8 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic *efx)
 	/* Insert/renew multicast filters */
 	if (table->stack_mc_count >= 0) {
 		for (i = 0; i < table->stack_mc_count; i++) {
-			efx_filter_init_rx(&spec, EFX_FILTER_PRI_REQUIRED,
-					   EFX_FILTER_FLAG_RX_RSS |
-					   EFX_FILTER_FLAG_RX_STACK,
+			efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO,
+					   EFX_FILTER_FLAG_RX_RSS,
 					   0);
 			efx_filter_set_eth_local(&spec, EFX_FILTER_VID_UNSPEC,
 						 table->stack_mc_list[i].addr);
@@ -3166,7 +3179,7 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic *efx)
 				/* Fall back to multicast-promisc */
 				while (i--)
 					efx_ef10_filter_remove_safe(
-						efx, EFX_FILTER_PRI_REQUIRED,
+						efx, EFX_FILTER_PRI_AUTO,
 						table->stack_mc_list[i].id);
 				table->stack_mc_count = -1;
 				break;
@@ -3175,9 +3188,8 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic *efx)
 		}
 	}
 	if (table->stack_mc_count < 0) {
-		efx_filter_init_rx(&spec, EFX_FILTER_PRI_REQUIRED,
-				   EFX_FILTER_FLAG_RX_RSS |
-				   EFX_FILTER_FLAG_RX_STACK,
+		efx_filter_init_rx(&spec, EFX_FILTER_PRI_AUTO,
+				   EFX_FILTER_FLAG_RX_RSS,
 				   0);
 		efx_filter_set_mc_def(&spec);
 		rc = efx_ef10_filter_insert(efx, &spec, true);
@@ -3197,9 +3209,8 @@ static void efx_ef10_filter_sync_rx_mode(struct efx_nic *efx)
 	for (i = 0; i < HUNT_FILTER_TBL_ROWS; i++) {
 		if (ACCESS_ONCE(table->entry[i].spec) &
 		    EFX_EF10_FILTER_FLAG_STACK_OLD) {
-			if (efx_ef10_filter_remove_internal(efx,
-					EFX_FILTER_PRI_REQUIRED,
-					i, true) < 0)
+			if (efx_ef10_filter_remove_internal(
+				    efx, EFX_FILTER_PRI_AUTO, i, true) < 0)
 				remove_failed = true;
 		}
 	}
diff --git a/drivers/net/ethernet/sfc/efx.h b/drivers/net/ethernet/sfc/efx.h
index a653786fbbe7..3a67030c73ea 100644
--- a/drivers/net/ethernet/sfc/efx.h
+++ b/drivers/net/ethernet/sfc/efx.h
@@ -138,6 +138,9 @@ efx_filter_get_filter_safe(struct efx_nic *efx,
  * efx_farch_filter_clear_rx - remove RX filters by priority
  * @efx: NIC from which to remove the filters
  * @priority: Maximum priority to remove
+ *
+ * Remove all RX filters whose priority is less than or equal to the
+ * given @priority and is not %EFX_FILTER_PRI_AUTO.
  */
 static inline void efx_filter_clear_rx(struct efx_nic *efx,
 				       enum efx_filter_priority priority)
diff --git a/drivers/net/ethernet/sfc/farch.c b/drivers/net/ethernet/sfc/farch.c
index 4c64ad7c9200..fbd923ddf546 100644
--- a/drivers/net/ethernet/sfc/farch.c
+++ b/drivers/net/ethernet/sfc/farch.c
@@ -2190,8 +2190,8 @@ efx_farch_filter_init_rx_for_stack(struct efx_nic *efx,
 	/* If there's only one channel then disable RSS for non VF
 	 * traffic, thereby allowing VFs to use RSS when the PF can't.
 	 */
-	spec->priority = EFX_FILTER_PRI_REQUIRED;
-	spec->flags = (EFX_FILTER_FLAG_RX | EFX_FILTER_FLAG_RX_STACK |
+	spec->priority = EFX_FILTER_PRI_AUTO;
+	spec->flags = (EFX_FILTER_FLAG_RX |
 		       (efx->n_rx_channels > 1 ? EFX_FILTER_FLAG_RX_RSS : 0) |
 		       (efx->rx_scatter ? EFX_FILTER_FLAG_RX_SCATTER : 0));
 	spec->dmaq_id = 0;
@@ -2456,20 +2456,13 @@ s32 efx_farch_filter_insert(struct efx_nic *efx,
 			rc = -EEXIST;
 			goto out;
 		}
-		if (spec.priority < saved_spec->priority &&
-		    !(saved_spec->priority == EFX_FILTER_PRI_REQUIRED &&
-		      saved_spec->flags & EFX_FILTER_FLAG_RX_STACK)) {
+		if (spec.priority < saved_spec->priority) {
 			rc = -EPERM;
 			goto out;
 		}
-		if (spec.flags & EFX_FILTER_FLAG_RX_STACK) {
-			/* Just make sure it won't be removed */
-			saved_spec->flags |= EFX_FILTER_FLAG_RX_STACK;
-			rc = 0;
-			goto out;
-		}
-		/* Retain the RX_STACK flag */
-		spec.flags |= saved_spec->flags & EFX_FILTER_FLAG_RX_STACK;
+		if (saved_spec->priority == EFX_FILTER_PRI_AUTO ||
+		    saved_spec->flags & EFX_FILTER_FLAG_RX_OVER_AUTO)
+			spec.flags |= EFX_FILTER_FLAG_RX_OVER_AUTO;
 	}
 
 	/* Insert the filter */
@@ -2553,7 +2546,7 @@ static int efx_farch_filter_remove(struct efx_nic *efx,
 	    spec->priority > priority)
 		return -ENOENT;
 
-	if (spec->flags & EFX_FILTER_FLAG_RX_STACK) {
+	if (spec->flags & EFX_FILTER_FLAG_RX_OVER_AUTO) {
 		efx_farch_filter_init_rx_for_stack(efx, spec);
 		efx_farch_filter_push_rx_config(efx);
 	} else {
@@ -2637,8 +2630,11 @@ efx_farch_filter_table_clear(struct efx_nic *efx,
 	unsigned int filter_idx;
 
 	spin_lock_bh(&efx->filter_lock);
-	for (filter_idx = 0; filter_idx < table->size; ++filter_idx)
-		efx_farch_filter_remove(efx, table, filter_idx, priority);
+	for (filter_idx = 0; filter_idx < table->size; ++filter_idx) {
+		if (table->spec[filter_idx].priority != EFX_FILTER_PRI_AUTO)
+			efx_farch_filter_remove(efx, table,
+						filter_idx, priority);
+	}
 	spin_unlock_bh(&efx->filter_lock);
 }
 
diff --git a/drivers/net/ethernet/sfc/filter.h b/drivers/net/ethernet/sfc/filter.h
index 63c77a557178..3ef298d3c47e 100644
--- a/drivers/net/ethernet/sfc/filter.h
+++ b/drivers/net/ethernet/sfc/filter.h
@@ -59,12 +59,16 @@ enum efx_filter_match_flags {
 /**
  * enum efx_filter_priority - priority of a hardware filter specification
  * @EFX_FILTER_PRI_HINT: Performance hint
+ * @EFX_FILTER_PRI_AUTO: Automatic filter based on device address list
+ *	or hardware requirements.  This may only be used by the filter
+ *	implementation for each NIC type.
  * @EFX_FILTER_PRI_MANUAL: Manually configured filter
  * @EFX_FILTER_PRI_REQUIRED: Required for correct behaviour (user-level
  *	networking and SR-IOV)
  */
 enum efx_filter_priority {
 	EFX_FILTER_PRI_HINT = 0,
+	EFX_FILTER_PRI_AUTO,
 	EFX_FILTER_PRI_MANUAL,
 	EFX_FILTER_PRI_REQUIRED,
 };
@@ -78,19 +82,18 @@ enum efx_filter_priority {
  *	according to the indirection table.
  * @EFX_FILTER_FLAG_RX_SCATTER: Enable DMA scatter on the receiving
  *	queue.
- * @EFX_FILTER_FLAG_RX_STACK: Indicates a filter inserted for the
- *	network stack.  The filter must have a priority of
- *	%EFX_FILTER_PRI_REQUIRED.  It can be steered by a replacement
- *	request with priority %EFX_FILTER_PRI_MANUAL, and a removal
- *	request with priority %EFX_FILTER_PRI_MANUAL will reset the
- *	steering (but not remove the filter).
+ * @EFX_FILTER_FLAG_RX_OVER_AUTO: Indicates a filter that is
+ *	overriding an automatic filter (priority
+ *	%EFX_FILTER_PRI_AUTO).  This may only be set by the filter
+ *	implementation for each type.  A removal request will restore
+ *	the automatic filter in its place.
  * @EFX_FILTER_FLAG_RX: Filter is for RX
  * @EFX_FILTER_FLAG_TX: Filter is for TX
  */
 enum efx_filter_flags {
 	EFX_FILTER_FLAG_RX_RSS = 0x01,
 	EFX_FILTER_FLAG_RX_SCATTER = 0x02,
-	EFX_FILTER_FLAG_RX_STACK = 0x04,
+	EFX_FILTER_FLAG_RX_OVER_AUTO = 0x04,
 	EFX_FILTER_FLAG_RX = 0x08,
 	EFX_FILTER_FLAG_TX = 0x10,
 };