From 7414f0f6c7d26cc2b3d7d7aa1a0e12a97f92f211 Mon Sep 17 00:00:00 2001
From: Vasiliy Ulyanov <v.ulyanov@samsung.com>
Date: Tue, 23 Jul 2013 12:33:54 +0400
Subject: [PATCH] [FIX] module_put issue on EC_IOCTL_STOP_AND_DETACH

---
 driver/device_driver.c | 10 ++--------
 driver/handlers_core.h |  1 +
 driver/storage.c       | 20 +++++++++++---------
 3 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/driver/device_driver.c b/driver/device_driver.c
index 993a807..d73b58b 100644
--- a/driver/device_driver.c
+++ b/driver/device_driver.c
@@ -505,7 +505,6 @@ static long device_ioctl (struct file *file UNUSED, unsigned int cmd, unsigned l
 		unsigned long dbi_flags;
 		struct dbi_modules_handlers *local_mh;
 		struct dbi_modules_handlers_info *local_mhi;
-		unsigned int local_module_refcount = 0;
 		int j;
 		dbi_module_callback dmc_stop;
 
@@ -563,14 +562,9 @@ static long device_ioctl (struct file *file UNUSED, unsigned int cmd, unsigned l
 sad_cleanup:
 		spin_lock_irqsave(&local_mh->lock, dbi_flags);
 		list_for_each_entry_rcu(local_mhi, &local_mh->modules_handlers, dbi_list_head) {
-			local_module_refcount = module_refcount(local_mhi->dbi_module);
-			if (local_module_refcount == 1) {
+			while (local_mhi->refcount > 0) {
 				module_put(local_mhi->dbi_module);
-			}
-			else if (local_module_refcount > 1) {
-				printk("local_module_refcount too much - force set refcount to zero\n");
-				while (local_module_refcount--)
-					module_put(local_mhi->dbi_module);
+				local_mhi->refcount--;
 			}
 		}
 		spin_unlock_irqrestore(&local_mh->lock, dbi_flags);
diff --git a/driver/handlers_core.h b/driver/handlers_core.h
index d708fac..fcbbf2e 100644
--- a/driver/handlers_core.h
+++ b/driver/handlers_core.h
@@ -38,6 +38,7 @@ struct dbi_modules_handlers_info {
 	int			dbi_module_priority_start;
 	int			dbi_module_priority_stop;
 	void *			(*get_uprobes)(void);
+	int refcount;
 };
 
 extern int dbi_register_handlers_module(struct dbi_modules_handlers_info *dbi_mhi);
diff --git a/driver/storage.c b/driver/storage.c
index bde6cfa..c7d82a8 100644
--- a/driver/storage.c
+++ b/driver/storage.c
@@ -88,7 +88,6 @@ static void dbi_find_and_set_handler_for_probe(kernel_probe_t *p)
 	unsigned long jp_handler_addr, rp_handler_addr;
 	struct dbi_modules_handlers_info *local_mhi;
 	unsigned long dbi_flags;
-	unsigned int local_module_refcount = 0;
 
 	spin_lock_irqsave(&dbi_mh.lock, dbi_flags);
 	list_for_each_entry_rcu(local_mhi, &dbi_mh.modules_handlers, dbi_list_head) {
@@ -101,14 +100,15 @@ static void dbi_find_and_set_handler_for_probe(kernel_probe_t *p)
 						(local_mhi->dbi_module)->name, p->addr);
 			}
 			else {
-				local_module_refcount = module_refcount(local_mhi->dbi_module);
-				if (local_module_refcount == 0) {
-					if (!try_module_get(local_mhi->dbi_module))
+				if (local_mhi->refcount == 0) {
+					if (!try_module_get(local_mhi->dbi_module)) {
 						printk("Error of try_module_get() for module %s\n",
 								(local_mhi->dbi_module)->name);
-					else
+					} else {
+						local_mhi->refcount++;
 						printk("Module %s in use now\n",
 								(local_mhi->dbi_module)->name);
+					}
 				}
 				p->jprobe.entry = (kprobe_opcode_t *)jp_handler_addr;
 				printk("Set jp_handler for %s module (address %0lX)\n",
@@ -121,14 +121,15 @@ static void dbi_find_and_set_handler_for_probe(kernel_probe_t *p)
 						(local_mhi->dbi_module)->name, p->addr);
 			}
 			else {
-				local_module_refcount = module_refcount(local_mhi->dbi_module);
-				if (local_module_refcount == 0) {
-					if (!try_module_get(local_mhi->dbi_module))
+				if (local_mhi->refcount == 0) {
+					if (!try_module_get(local_mhi->dbi_module)) {
 						printk("Error of try_module_get() for module %s\n",
 								(local_mhi->dbi_module)->name);
-					else
+					} else {
+						local_mhi->refcount++;
 						printk("Module %s in use now\n",
 								(local_mhi->dbi_module)->name);
+					}
 				}
 				p->retprobe.handler = (kretprobe_handler_t)rp_handler_addr;
 				printk("Set rp_handler for %s module (address %0lX)\n",
@@ -171,6 +172,7 @@ int dbi_register_handlers_module(struct dbi_modules_handlers_info *dbi_mhi)
 	spin_lock_irqsave(&dbi_mh.lock, dbi_flags);
 //	local_mhi = container_of(&dbi_mhi->dbi_list_head, struct dbi_modules_handlers_info, dbi_list_head);
 	list_add_rcu(&dbi_mhi->dbi_list_head, &dbi_mh.modules_handlers);
+	dbi_mhi->refcount = 0;
 	printk("Added module %s (head is %p)\n", (dbi_mhi->dbi_module)->name, &dbi_mhi->dbi_list_head);
 	spin_unlock_irqrestore(&dbi_mh.lock, dbi_flags);
 	return 0;
-- 
2.7.4