[PATCH 0/5] Allow opal-async waiters to get interrupted

@@ -294,6 +294,7 @@ extern void opal_notifier_update_evt(uint64_t evt_mask, uint64_t evt_val);
 extern int opal_async_get_token_interruptible(void);
 extern int opal_async_release_token(int token);
 extern int opal_async_wait_response(uint64_t token, struct opal_msg *msg);
+int opal_async_wait_response_interruptible(uint64_t token, struct opal_msg *msg);
 extern int opal_get_sensor_data(u32 sensor_hndl, u32 *sensor_data);
 
 struct rtc_time;

@@ -26,6 +26,8 @@
 enum opal_async_token_state {
 	ASYNC_TOKEN_FREE,
 	ASYNC_TOKEN_ALLOCATED,
+	ASYNC_TOKEN_DISPATCHED,
+	ASYNC_TOKEN_ABANDONED,
 	ASYNC_TOKEN_COMPLETED
 };
 

@@ -61,8 +63,10 @@ static int __opal_async_get_token(void)
 }
 
 /*
- * Note: If the returned token is used in an opal call and opal returns
- * OPAL_ASYNC_COMPLETION you MUST opal_async_wait_response() before
+ * Note: If the returned token is used in an opal call and opal
+ * returns OPAL_ASYNC_COMPLETION you MUST one of
+ * opal_async_wait_response() or
+ * opal_async_wait_response_interruptible() at least once before
  * calling another other opal_async_* function
  */
 int opal_async_get_token_interruptible(void)

@@ -99,6 +103,16 @@ static int __opal_async_release_token(int token)
 			opal_async_tokens[token].state = ASYNC_TOKEN_FREE;
 			rc = 0;
 			break;
+		/*
+		 * DISPATCHED and ABANDONED tokens must wait for OPAL to
+		 * respond.
+		 * Mark a DISPATCHED token as ABANDONED so that the response
+		 * response handling code knows no one cares and that it can
+		 * free it then.
+		 */
+		case ASYNC_TOKEN_DISPATCHED:
+			opal_async_tokens[token].state = ASYNC_TOKEN_ABANDONED;
+			/* Fall through */
 		default:
 			rc = 1;
 	}

@@ -131,7 +145,11 @@ int opal_async_wait_response(uint64_t token, struct opal_msg *msg)
 		return -EINVAL;
 	}
 
-	/* Wakeup the poller before we wait for events to speed things
+	/*
+	 * There is no need to mark the token as dispatched, wait_event()
+	 * will block until the token completes.
+	 *
+	 * Wakeup the poller before we wait for events to speed things
 	 * up on platforms or simulators where the interrupts aren't
 	 * functional.
 	 */

@@ -144,11 +162,66 @@ int opal_async_wait_response(uint64_t token, struct opal_msg *msg)
 }
 EXPORT_SYMBOL_GPL(opal_async_wait_response);
 
+int opal_async_wait_response_interruptible(uint64_t token, struct opal_msg *msg)
+{
+	unsigned long flags;
+	int ret;
+
+	if (token >= opal_max_async_tokens) {
+		pr_err("%s: Invalid token passed\n", __func__);
+		return -EINVAL;
+	}
+
+	if (!msg) {
+		pr_err("%s: Invalid message pointer passed\n", __func__);
+		return -EINVAL;
+	}
+
+	/*
+	 * The first time this gets called we mark the token as DISPATCHED
+	 * so that if wait_event_interruptible() returns not zero and the
+	 * caller frees the token, we know not to actually free the token
+	 * until the response comes.
+	 *
+	 * Only change if the token is ALLOCATED - it may have been
+	 * completed even before the caller gets around to calling this
+	 * the first time.
+	 *
+	 * There is also a dirty great comment at the token allocation
+	 * function that if the opal call returns OPAL_ASYNC_COMPLETION to
+	 * the caller then the caller *must* call this or the not
+	 * interruptible version before doing anything else with the
+	 * token.
+	 */
+	if (opal_async_tokens[token].state == ASYNC_TOKEN_ALLOCATED) {
+		spin_lock_irqsave(&opal_async_comp_lock, flags);
+		if (opal_async_tokens[token].state == ASYNC_TOKEN_ALLOCATED) {
+			opal_async_tokens[token].state = ASYNC_TOKEN_DISPATCHED;
+		}
+		spin_unlock_irqrestore(&opal_async_comp_lock, flags);
+	}
+
+	/* Wakeup the poller before we wait for events to speed things
+	 * up on platforms or simulators where the interrupts aren't
+	 * functional.
+	 */
+	opal_wake_poller();
+	ret = wait_event_interruptible(opal_async_wait,
+			opal_async_tokens[token].state == ASYNC_TOKEN_COMPLETED);
+	if (!ret) {
+		memcpy(msg, &opal_async_tokens[token].response, sizeof(*msg));
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(opal_async_wait_response_interruptible);
+
 /* Called from interrupt context */
 static int opal_async_comp_event(struct notifier_block *nb,
 		unsigned long msg_type, void *msg)
 {
 	struct opal_msg *comp_msg = msg;
+	enum opal_async_token_state state;
 	unsigned long flags;
 	uint64_t token;
 

@@ -156,11 +229,17 @@ static int opal_async_comp_event(struct notifier_block *nb,
 		return 0;
 
 	token = be64_to_cpu(comp_msg->params[0]);
-	memcpy(&opal_async_tokens[token].response, comp_msg, sizeof(*comp_msg));
 	spin_lock_irqsave(&opal_async_comp_lock, flags);
+	state = opal_async_tokens[token].state;
 	opal_async_tokens[token].state = ASYNC_TOKEN_COMPLETED;
 	spin_unlock_irqrestore(&opal_async_comp_lock, flags);
 
+	if (state == ASYNC_TOKEN_ABANDONED) {
+		/* Free the token, no one else will */
+		opal_async_release_token(token);
+		return 0;
+	}
+	memcpy(&opal_async_tokens[token].response, comp_msg, sizeof(*comp_msg));
 	wake_up(&opal_async_wait);
 
 	return 0;

@@ -930,6 +930,7 @@ int opal_error_code(int rc)
 
 	case OPAL_PARAMETER:		return -EINVAL;
 	case OPAL_ASYNC_COMPLETION:	return -EINPROGRESS;
+	case OPAL_BUSY:
 	case OPAL_BUSY_EVENT:		return -EBUSY;
 	case OPAL_NO_MEM:		return -ENOMEM;
 	case OPAL_PERMISSION:		return -EPERM;

@@ -1,7 +1,7 @@
 /*
  * PowerNV OPAL asynchronous completion interfaces
  *
- * Copyright 2013 IBM Corp.
+ * Copyright 2013-2017 IBM Corp.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License

@@ -23,40 +23,48 @@
 #include <asm/machdep.h>
 #include <asm/opal.h>
 
-#define N_ASYNC_COMPLETIONS	64
+enum opal_async_token_state {
+	ASYNC_TOKEN_FREE,
+	ASYNC_TOKEN_ALLOCATED,
+	ASYNC_TOKEN_COMPLETED
+};
+
+struct opal_async_token {
+	enum opal_async_token_state state;
+	struct opal_msg *response;
+};
 
-static DECLARE_BITMAP(opal_async_complete_map, N_ASYNC_COMPLETIONS) = {~0UL};
-static DECLARE_BITMAP(opal_async_token_map, N_ASYNC_COMPLETIONS);
 static DECLARE_WAIT_QUEUE_HEAD(opal_async_wait);
 static DEFINE_SPINLOCK(opal_async_comp_lock);
 static struct semaphore opal_async_sem;
-static struct opal_msg *opal_async_responses;
 static unsigned int opal_max_async_tokens;
+static struct opal_async_token *opal_async_tokens;
 
 static int __opal_async_get_token(void)
 {
 	unsigned long flags;
 	int token;
 
-	spin_lock_irqsave(&opal_async_comp_lock, flags);
-	token = find_first_bit(opal_async_complete_map, opal_max_async_tokens);
-	if (token >= opal_max_async_tokens) {
-		token = -EBUSY;
-		goto out;
+	for (token = 0; token < opal_max_async_tokens; token++) {
+		if (opal_async_tokens[token].state == ASYNC_TOKEN_FREE) {
+			spin_lock_irqsave(&opal_async_comp_lock, flags);
+			if (opal_async_tokens[token].state == ASYNC_TOKEN_FREE) {
+				opal_async_tokens[token].state = ASYNC_TOKEN_ALLOCATED;
+				spin_unlock_irqrestore(&opal_async_comp_lock, flags);
+				return token;
+			}
+			spin_unlock_irqrestore(&opal_async_comp_lock, flags);
+		}
 	}
 
-	if (__test_and_set_bit(token, opal_async_token_map)) {
-		token = -EBUSY;
-		goto out;
-	}
-
-	__clear_bit(token, opal_async_complete_map);
-
-out:
-	spin_unlock_irqrestore(&opal_async_comp_lock, flags);
-	return token;
+	return -EBUSY;
 }
 
+/*
+ * Note: If the returned token is used in an opal call and opal returns
+ * OPAL_ASYNC_COMPLETION you MUST opal_async_wait_response() before
+ * calling another other opal_async_* function
+ */
 int opal_async_get_token_interruptible(void)
 {
 	int token;

@@ -76,6 +84,7 @@ EXPORT_SYMBOL_GPL(opal_async_get_token_interruptible);
 static int __opal_async_release_token(int token)
 {
 	unsigned long flags;
+	int rc;
 
 	if (token < 0 || token >= opal_max_async_tokens) {
 		pr_err("%s: Passed token is out of range, token %d\n",

@@ -84,11 +93,18 @@ static int __opal_async_release_token(int token)
 	}
 
 	spin_lock_irqsave(&opal_async_comp_lock, flags);
-	__set_bit(token, opal_async_complete_map);
-	__clear_bit(token, opal_async_token_map);
+	switch (opal_async_tokens[token].state) {
+		case ASYNC_TOKEN_COMPLETED:
+		case ASYNC_TOKEN_ALLOCATED:
+			opal_async_tokens[token].state = ASYNC_TOKEN_FREE;
+			rc = 0;
+			break;
+		default:
+			rc = 1;
+	}
 	spin_unlock_irqrestore(&opal_async_comp_lock, flags);
 
-	return 0;
+	return rc;
 }
 
 int opal_async_release_token(int token)

@@ -96,12 +112,10 @@ int opal_async_release_token(int token)
 	int ret;
 
 	ret = __opal_async_release_token(token);
-	if (ret)
-		return ret;
-
-	up(&opal_async_sem);
+	if (!ret)
+		up(&opal_async_sem);
 
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(opal_async_release_token);
 

@@ -122,13 +136,15 @@ int opal_async_wait_response(uint64_t token, struct opal_msg *msg)
 	 * functional.
 	 */
 	opal_wake_poller();
-	wait_event(opal_async_wait, test_bit(token, opal_async_complete_map));
-	memcpy(msg, &opal_async_responses[token], sizeof(*msg));
+	wait_event(opal_async_wait,
+			opal_async_tokens[token].state == ASYNC_TOKEN_COMPLETED);
+	memcpy(msg, &opal_async_tokens[token].response, sizeof(*msg));
 
 	return 0;
 }
 EXPORT_SYMBOL_GPL(opal_async_wait_response);
 
+/* Called from interrupt context */
 static int opal_async_comp_event(struct notifier_block *nb,
 		unsigned long msg_type, void *msg)
 {

@@ -140,9 +156,9 @@ static int opal_async_comp_event(struct notifier_block *nb,
 		return 0;
 
 	token = be64_to_cpu(comp_msg->params[0]);
-	memcpy(&opal_async_responses[token], comp_msg, sizeof(*comp_msg));
+	memcpy(&opal_async_tokens[token].response, comp_msg, sizeof(*comp_msg));
 	spin_lock_irqsave(&opal_async_comp_lock, flags);
-	__set_bit(token, opal_async_complete_map);
+	opal_async_tokens[token].state = ASYNC_TOKEN_COMPLETED;
 	spin_unlock_irqrestore(&opal_async_comp_lock, flags);
 
 	wake_up(&opal_async_wait);

@@ -178,24 +194,19 @@ int __init opal_async_comp_init(void)
 	}
 
 	opal_max_async_tokens = be32_to_cpup(async);
-	if (opal_max_async_tokens > N_ASYNC_COMPLETIONS)
-		opal_max_async_tokens = N_ASYNC_COMPLETIONS;
+	opal_async_tokens = kzalloc(opal_max_async_tokens * sizeof(*opal_async_tokens),
+			GFP_KERNEL);
+	if (!opal_async_tokens) {
+		err = -ENOMEM;
+		goto out_opal_node;
+	}
 
 	err = opal_message_notifier_register(OPAL_MSG_ASYNC_COMP,
 			&opal_async_comp_nb);
 	if (err) {
 		pr_err("%s: Can't register OPAL event notifier (%d)\n",
 				__func__, err);
-		goto out_opal_node;
-	}
-
-	opal_async_responses = kzalloc(
-			sizeof(*opal_async_responses) * opal_max_async_tokens,
-			GFP_KERNEL);
-	if (!opal_async_responses) {
-		pr_err("%s: Out of memory, failed to do asynchronous "
-				"completion init\n", __func__);
-		err = -ENOMEM;
+		kfree(opal_async_tokens);
 		goto out_opal_node;
 	}
 

@@ -88,19 +88,23 @@ static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op,
 	}
 
 	if (rc != OPAL_ASYNC_COMPLETION) {
-		dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n",
-				op, rc);
+		if (rc != OPAL_BUSY)
+			dev_err(dev, "opal_flash_async_op(op=%d) failed (rc %d)\n",
+					op, rc);
 		opal_async_release_token(token);
-		rc = -EIO;
+		rc = opal_error_code(rc);
 		goto out;
 	}
 
-	rc = opal_async_wait_response(token, &msg);
+	rc = opal_async_wait_response_interruptible(token, &msg);
 	opal_async_release_token(token);
 	mutex_unlock(&info->lock);
 	if (rc) {
-		dev_err(dev, "opal async wait failed (rc %d)\n", rc);
-		return -EIO;
+		if (rc == -ERESTARTSYS)
+			rc = -EINTR;
+		else
+			dev_err(dev, "opal async wait failed (rc %d)\n", rc);
+		return rc;
 	}
 
 	rc = opal_get_async_rc(msg);

@@ -109,7 +113,7 @@ static int powernv_flash_async_op(struct mtd_info *mtd, enum flash_op op,
 		if (retlen)
 			*retlen = len;
 	} else {
-		rc = -EIO;
+		rc = opal_error_code(rc);
 	}
 
 	return rc;

@@ -291,9 +291,7 @@ extern void opal_notifier_enable(void);
 extern void opal_notifier_disable(void);
 extern void opal_notifier_update_evt(uint64_t evt_mask, uint64_t evt_val);
 
-extern int __opal_async_get_token(void);
 extern int opal_async_get_token_interruptible(void);
-extern int __opal_async_release_token(int token);
 extern int opal_async_release_token(int token);
 extern int opal_async_wait_response(uint64_t token, struct opal_msg *msg);
 extern int opal_get_sensor_data(u32 sensor_hndl, u32 *sensor_data);

@@ -33,7 +33,7 @@ static struct semaphore opal_async_sem;
 static struct opal_msg *opal_async_responses;
 static unsigned int opal_max_async_tokens;
 
-int __opal_async_get_token(void)
+static int __opal_async_get_token(void)
 {
 	unsigned long flags;
 	int token;

@@ -73,7 +73,7 @@ int opal_async_get_token_interruptible(void)
 }
 EXPORT_SYMBOL_GPL(opal_async_get_token_interruptible);
 
-int __opal_async_release_token(int token)
+static int __opal_async_release_token(int token)
 {
 	unsigned long flags;
 

@@ -199,11 +199,7 @@ int __init opal_async_comp_init(void)
 		goto out_opal_node;
 	}
 
-	/* Initialize to 1 less than the maximum tokens available, as we may
-	 * require to pop one during emergency through synchronous call to
-	 * __opal_async_get_token()
-	 */
-	sema_init(&opal_async_sem, opal_max_async_tokens - 1);
+	sema_init(&opal_async_sem, opal_max_async_tokens);
 
 out_opal_node:
 	of_node_put(opal_node);