Merge branch 'ipa-fixes'

Alex Elder says:

====================
net: ipa: fix two replenish bugs

This series contains two fixes for bugs in the IPA receive buffer
replenishing code.  The (new) second patch defines a bitmap to
represent endpoint the replenish enabled flag.  Its purpose is to
prepare for the third patch, which adds an additional flag.

Version 2 of this series uses bitmap operations in the second bug
fix rather than an atomic variable, as suggested by Jakub.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 35 insertions, 10 deletions

diff --git a/drivers/net/ipa/ipa_endpoint.c b/drivers/net/ipa/ipa_endpoint.c
index 49d9a077d037..68291a3efd04 100644
--- a/drivers/net/ipa/ipa_endpoint.c
+++ b/drivers/net/ipa/ipa_endpoint.c
@@ -1080,27 +1080,38 @@ static void ipa_endpoint_replenish(struct ipa_endpoint *endpoint, bool add_one)
 {
 	struct gsi *gsi;
 	u32 backlog;
+	int delta;
 
-	if (!endpoint->replenish_enabled) {
+	if (!test_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags)) {
 		if (add_one)
 			atomic_inc(&endpoint->replenish_saved);
 		return;
 	}
 
+	/* If already active, just update the backlog */
+	if (test_and_set_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags)) {
+		if (add_one)
+			atomic_inc(&endpoint->replenish_backlog);
+		return;
+	}
+
 	while (atomic_dec_not_zero(&endpoint->replenish_backlog))
 		if (ipa_endpoint_replenish_one(endpoint))
 			goto try_again_later;
+
+	clear_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags);
+
 	if (add_one)
 		atomic_inc(&endpoint->replenish_backlog);
 
 	return;
 
 try_again_later:
-	/* The last one didn't succeed, so fix the backlog */
-	backlog = atomic_inc_return(&endpoint->replenish_backlog);
+	clear_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags);
 
-	if (add_one)
-		atomic_inc(&endpoint->replenish_backlog);
+	/* The last one didn't succeed, so fix the backlog */
+	delta = add_one ? 2 : 1;
+	backlog = atomic_add_return(delta, &endpoint->replenish_backlog);
 
 	/* Whenever a receive buffer transaction completes we'll try to
 	 * replenish again.  It's unlikely, but if we fail to supply even
@@ -1120,7 +1131,7 @@ static void ipa_endpoint_replenish_enable(struct ipa_endpoint *endpoint)
 	u32 max_backlog;
 	u32 saved;
 
-	endpoint->replenish_enabled = true;
+	set_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags);
 	while ((saved = atomic_xchg(&endpoint->replenish_saved, 0)))
 		atomic_add(saved, &endpoint->replenish_backlog);
 
@@ -1134,7 +1145,7 @@ static void ipa_endpoint_replenish_disable(struct ipa_endpoint *endpoint)
 {
 	u32 backlog;
 
-	endpoint->replenish_enabled = false;
+	clear_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags);
 	while ((backlog = atomic_xchg(&endpoint->replenish_backlog, 0)))
 		atomic_add(backlog, &endpoint->replenish_saved);
 }
@@ -1691,7 +1702,8 @@ static void ipa_endpoint_setup_one(struct ipa_endpoint *endpoint)
 		/* RX transactions require a single TRE, so the maximum
 		 * backlog is the same as the maximum outstanding TREs.
 		 */
-		endpoint->replenish_enabled = false;
+		clear_bit(IPA_REPLENISH_ENABLED, endpoint->replenish_flags);
+		clear_bit(IPA_REPLENISH_ACTIVE, endpoint->replenish_flags);
 		atomic_set(&endpoint->replenish_saved,
 			   gsi_channel_tre_max(gsi, endpoint->channel_id));
 		atomic_set(&endpoint->replenish_backlog, 0);
diff --git a/drivers/net/ipa/ipa_endpoint.h b/drivers/net/ipa/ipa_endpoint.h
index 0a859d10312d..0313cdc607de 100644
--- a/drivers/net/ipa/ipa_endpoint.h
+++ b/drivers/net/ipa/ipa_endpoint.h
@@ -41,6 +41,19 @@ enum ipa_endpoint_name {
 #define IPA_ENDPOINT_MAX		32	/* Max supported by driver */
 
 /**
+ * enum ipa_replenish_flag:	RX buffer replenish flags
+ *
+ * @IPA_REPLENISH_ENABLED:	Whether receive buffer replenishing is enabled
+ * @IPA_REPLENISH_ACTIVE:	Whether replenishing is underway
+ * @IPA_REPLENISH_COUNT:	Number of defined replenish flags
+ */
+enum ipa_replenish_flag {
+	IPA_REPLENISH_ENABLED,
+	IPA_REPLENISH_ACTIVE,
+	IPA_REPLENISH_COUNT,	/* Number of flags (must be last) */
+};
+
+/**
  * struct ipa_endpoint - IPA endpoint information
  * @ipa:		IPA pointer
  * @ee_id:		Execution environmnent endpoint is associated with
@@ -51,7 +64,7 @@ enum ipa_endpoint_name {
  * @trans_tre_max:	Maximum number of TRE descriptors per transaction
  * @evt_ring_id:	GSI event ring used by the endpoint
  * @netdev:		Network device pointer, if endpoint uses one
- * @replenish_enabled:	Whether receive buffer replenishing is enabled
+ * @replenish_flags:	Replenishing state flags
  * @replenish_ready:	Number of replenish transactions without doorbell
  * @replenish_saved:	Replenish requests held while disabled
  * @replenish_backlog:	Number of buffers needed to fill hardware queue
@@ -72,7 +85,7 @@ struct ipa_endpoint {
 	struct net_device *netdev;
 
 	/* Receive buffer replenishing for RX endpoints */
-	bool replenish_enabled;
+	DECLARE_BITMAP(replenish_flags, IPA_REPLENISH_COUNT);
 	u32 replenish_ready;
 	atomic_t replenish_saved;
 	atomic_t replenish_backlog;