From: Vyacheslav Cherkashin <v.cherkashin@samsung.com>
Date: Mon, 11 Apr 2016 14:48:54 +0000 (+0300)
Subject: [IMPROVE] synchronize usage of sspt_file.htable.heads
X-Git-Tag: submit/tizen/20161124.145503~40^2~10
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d76eb3439e388dcda50710c64d3e2fad563cc1a0;p=kernel%2Fswap-modules.git

[IMPROVE] synchronize usage of sspt_file.htable.heads

Change-Id: I4fc0715b3a0ac9a06e59ffec112b0b412a640eca
Signed-off-by: Vyacheslav Cherkashin <v.cherkashin@samsung.com>
---

diff --git a/us_manager/sspt/sspt_debug.h b/us_manager/sspt/sspt_debug.h
index a6830ff..18e34b9 100644
--- a/us_manager/sspt/sspt_debug.h
+++ b/us_manager/sspt/sspt_debug.h
@@ -71,7 +71,7 @@ static inline void print_page_probes(const struct sspt_page *page)
 	}
 }
 
-static inline void print_file_probes(const struct sspt_file *file)
+static inline void print_file_probes(struct sspt_file *file)
 {
 	int i;
 	unsigned long table_size;
@@ -93,12 +93,14 @@ static inline void print_file_probes(const struct sspt_file *file)
 	       "table_size=%lu, vm_start=%lx\n",
 	       file->dentry->d_iname, name, table_size, file->vm_start);
 
+	down_read(&file->htable.sem);
 	for (i = 0; i < table_size; ++i) {
 		head = &file->htable.heads[i];
 		swap_hlist_for_each_entry_rcu(page, node, head, hlist) {
 			print_page_probes(page);
 		}
 	}
+	up_read(&file->htable.sem);
 }
 
 static inline void print_proc_probes(struct sspt_proc *proc)
diff --git a/us_manager/sspt/sspt_file.c b/us_manager/sspt/sspt_file.c
index c700f39..c55da68 100644
--- a/us_manager/sspt/sspt_file.c
+++ b/us_manager/sspt/sspt_file.c
@@ -48,17 +48,20 @@ static unsigned long htable_size(const struct sspt_file *file)
 	return 1 << file->htable.bits;
 }
 
-static struct hlist_head *htable_head_by_key(const struct sspt_file *file,
-					     unsigned long offset)
-{
-	return &file->htable.heads[hash_ptr((void *)offset, file->htable.bits)];
-}
-
 static struct hlist_head *htable_head_by_idx(const struct sspt_file *file,
 					     unsigned long idx)
 {
 	return &file->htable.heads[idx];
 }
+
+static struct hlist_head *htable_head_by_key(const struct sspt_file *file,
+					     unsigned long offset)
+{
+	unsigned long idx = hash_ptr((void *)offset, file->htable.bits);
+
+	return htable_head_by_idx(file, idx);
+}
+
 /**
  * @brief Create sspt_file struct
  *
@@ -93,6 +96,8 @@ struct sspt_file *sspt_file_create(struct dentry *dentry, int page_cnt)
 		INIT_HLIST_HEAD(&heads[i]);
 
 	obj->htable.heads = heads;
+	init_rwsem(&obj->htable.sem);
+
 	return obj;
 
 err:
@@ -114,6 +119,7 @@ void sspt_file_free(struct sspt_file *file)
 	struct hlist_node *n;
 	DECLARE_NODE_PTR_FOR_HLIST(p);
 
+	down_write(&file->htable.sem);
 	for (i = 0; i < table_size; ++i) {
 		head = htable_head_by_idx(file, i);
 		swap_hlist_for_each_entry_safe(page, p, n, head, hlist) {
@@ -121,6 +127,7 @@ void sspt_file_free(struct sspt_file *file)
 			sspt_page_free(page);
 		}
 	}
+	up_write(&file->htable.sem);
 
 	kfree(file->htable.heads);
 	kfree(file);
@@ -150,13 +157,16 @@ static struct sspt_page *sspt_find_page(struct sspt_file *file,
 static struct sspt_page *sspt_find_page_or_new(struct sspt_file *file,
 					       unsigned long offset)
 {
-	struct sspt_page *page = sspt_find_page(file, offset);
+	struct sspt_page *page;
 
+	down_write(&file->htable.sem);
+	page = sspt_find_page(file, offset);
 	if (page == NULL) {
 		page = sspt_page_create(offset);
 		if (page)
 			sspt_add_page(file, page);
 	}
+	up_write(&file->htable.sem);
 
 	return page;
 }
@@ -172,6 +182,7 @@ struct sspt_page *sspt_find_page_mapped(struct sspt_file *file,
 					unsigned long page)
 {
 	unsigned long offset;
+	struct sspt_page *p;
 
 	if (file->vm_start > page || file->vm_end < page) {
 		/* TODO: or panic?! */
@@ -185,7 +196,11 @@ struct sspt_page *sspt_find_page_mapped(struct sspt_file *file,
 
 	offset = page - file->vm_start;
 
-	return sspt_find_page(file, offset);
+	down_read(&file->htable.sem);
+	p = sspt_find_page(file, offset);
+	up_read(&file->htable.sem);
+
+	return p;
 }
 
 /**
@@ -226,11 +241,13 @@ void sspt_file_on_each_ip(struct sspt_file *file,
 	struct hlist_head *head;
 	DECLARE_NODE_PTR_FOR_HLIST(node);
 
+	down_read(&file->htable.sem);
 	for (i = 0; i < table_size; ++i) {
 		head = htable_head_by_idx(file, i);
 		swap_hlist_for_each_entry(page, node, head, hlist)
 			sspt_page_on_each_ip(page, func, data);
 	}
+	up_read(&file->htable.sem);
 }
 
 /**
@@ -243,22 +260,28 @@ void sspt_file_on_each_ip(struct sspt_file *file,
  */
 int sspt_file_check_install_pages(struct sspt_file *file)
 {
+	int ret = 0;
 	int i, table_size;
 	struct sspt_page *page;
 	struct hlist_head *head;
-	struct hlist_node *tmp;
 	DECLARE_NODE_PTR_FOR_HLIST(node);
 
 	table_size = htable_size(file);
+
+	down_read(&file->htable.sem);
 	for (i = 0; i < table_size; ++i) {
 		head = htable_head_by_idx(file, i);
-		swap_hlist_for_each_entry_safe(page, node, tmp, head, hlist) {
-			if (sspt_page_is_installed(page))
-				return 1;
+		swap_hlist_for_each_entry(page, node, head, hlist) {
+			if (sspt_page_is_installed(page)) {
+				ret = 1;
+				goto unlock;
+			}
 		}
 	}
 
-	return 0;
+unlock:
+	up_read(&file->htable.sem);
+	return ret;
 }
 
 /**
@@ -276,9 +299,10 @@ void sspt_file_install(struct sspt_file *file)
 	struct mm_struct *mm;
 	DECLARE_NODE_PTR_FOR_HLIST(node);
 
+	down_read(&file->htable.sem);
 	for (i = 0; i < table_size; ++i) {
 		head = htable_head_by_idx(file, i);
-		swap_hlist_for_each_entry_rcu(page, node, head, hlist) {
+		swap_hlist_for_each_entry(page, node, head, hlist) {
 			page_addr = file->vm_start + page->offset;
 			if (page_addr < file->vm_start ||
 			    page_addr >= file->vm_end)
@@ -289,6 +313,7 @@ void sspt_file_install(struct sspt_file *file)
 				sspt_register_page(page, file);
 		}
 	}
+	up_read(&file->htable.sem);
 }
 
 /**
@@ -307,20 +332,22 @@ int sspt_file_uninstall(struct sspt_file *file,
 	int table_size = htable_size(file);
 	struct sspt_page *page;
 	struct hlist_head *head;
-	struct hlist_node *tmp;
 	DECLARE_NODE_PTR_FOR_HLIST(node);
 
+	down_read(&file->htable.sem);
 	for (i = 0; i < table_size; ++i) {
 		head = htable_head_by_idx(file, i);
-		swap_hlist_for_each_entry_safe(page, node, tmp, head, hlist) {
+		swap_hlist_for_each_entry(page, node, head, hlist) {
 			err = sspt_unregister_page(page, flag, task);
 			if (err != 0) {
 				printk(KERN_INFO "ERROR sspt_file_uninstall: "
 				       "err=%d\n", err);
+				up_read(&file->htable.sem);
 				return err;
 			}
 		}
 	}
+	up_read(&file->htable.sem);
 
 	if (flag != US_DISARM) {
 		file->loaded = 0;
diff --git a/us_manager/sspt/sspt_file.h b/us_manager/sspt/sspt_file.h
index 3bda6ce..38d34aa 100644
--- a/us_manager/sspt/sspt_file.h
+++ b/us_manager/sspt/sspt_file.h
@@ -26,6 +26,7 @@
 
 #include "sspt_ip.h"
 #include <linux/types.h>
+#include <linux/rwsem.h>
 
 enum US_FLAGS;
 struct vm_area_struct;
@@ -41,6 +42,7 @@ struct sspt_file {
 
 	/* sspt_page */
 	struct {
+		struct rw_semaphore sem;	/**< Semaphore for hash-table */
 		unsigned long bits;		/**< Hash-table size */
 		struct hlist_head *heads;	/**< Heads for pages */
 	} htable;