1 files changed, 51 insertions, 41 deletions

diff --git a/arch/powerpc/platforms/powernv/opal-async.c b/arch/powerpc/platforms/powernv/opal-async.c
index 64255d3ee14a..a8a57310759a 100644
--- a/arch/powerpc/platforms/powernv/opal-async.c
+++ b/arch/powerpc/platforms/powernv/opal-async.c
@@ -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 +23,47 @@
 #include <asm/machdep.h>
 #include <asm/opal.h>
 
-#define N_ASYNC_COMPLETIONS	64
+enum opal_async_token_state {
+	ASYNC_TOKEN_UNALLOCATED = 0,
+	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;
+	int i, token = -EBUSY;
 
 	spin_lock_irqsave(&opal_async_comp_lock, flags);
-	token = find_first_zero_bit(opal_async_token_map, opal_max_async_tokens);
-	if (token >= opal_max_async_tokens) {
-		token = -EBUSY;
-		goto out;
-	}
 
-	if (!__test_and_clear_bit(token, opal_async_complete_map)) {
-		token = -EBUSY;
-		goto out;
+	for (i = 0; i < opal_max_async_tokens; i++) {
+		if (opal_async_tokens[i].state == ASYNC_TOKEN_UNALLOCATED) {
+			opal_async_tokens[i].state = ASYNC_TOKEN_ALLOCATED;
+			token = i;
+			break;
+		}
 	}
 
-	__set_bit(token, opal_async_token_map);
-
-out:
 	spin_unlock_irqrestore(&opal_async_comp_lock, flags);
 	return token;
 }
 
+/*
+ * Note: If the returned token is used in an opal call and opal returns
+ * OPAL_ASYNC_COMPLETION you MUST call opal_async_wait_response() before
+ * calling another other opal_async_* function
+ */
 int opal_async_get_token_interruptible(void)
 {
 	int token;
@@ -76,6 +83,7 @@ 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 +92,18 @@ 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_UNALLOCATED;
+		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 +111,10 @@ 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 +135,15 @@ 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 +155,9 @@ 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 +193,19 @@ 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 = kcalloc(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;
 	}