linux-kernel - [PATCH v2 5/6] zram: introduce zram data accessor

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Message-ID: <1492052365-16169-6-git-send-email-minchan@kernel.org>
Date:   Thu, 13 Apr 2017 11:59:24 +0900
From:   Minchan Kim <minchan@...nel.org>
To:     Andrew Morton <akpm@...ux-foundation.org>
CC:     <kernel-team@....com>, <linux-kernel@...r.kernel.org>,
        Minchan Kim <minchan@...nel.org>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Subject: [PATCH v2 5/6] zram: introduce zram data accessor

With element, sometime I got confused handle and element access.
It might be my bad but I think it's time to introduce accessor
to prevent future idiot like me.
This patch is just clean-up patch so it shouldn't change any
behavior.

Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Signed-off-by: Minchan Kim <minchan@...nel.org>
---
 drivers/block/zram/zram_drv.c | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 002019a552af..22b249444010 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -57,6 +57,16 @@ static inline struct zram *dev_to_zram(struct device *dev)
 	return (struct zram *)dev_to_disk(dev)->private_data;
 }
 
+static unsigned long zram_get_handle(struct zram *zram, u32 index)
+{
+	return zram->table[index].handle;
+}
+
+static void zram_set_handle(struct zram *zram, u32 index, unsigned long handle)
+{
+	zram->table[index].handle = handle;
+}
+
 /* flag operations require table entry bit_spin_lock() being held */
 static int zram_test_flag(struct zram *zram, u32 index,
 			enum zram_pageflags flag)
@@ -82,9 +92,9 @@ static inline void zram_set_element(struct zram *zram, u32 index,
 	zram->table[index].element = element;
 }
 
-static inline void zram_clear_element(struct zram *zram, u32 index)
+static unsigned long zram_get_element(struct zram *zram, u32 index)
 {
-	zram->table[index].element = 0;
+	return zram->table[index].element;
 }
 
 static size_t zram_get_obj_size(struct zram *zram, u32 index)
@@ -427,13 +437,14 @@ static bool zram_same_page_read(struct zram *zram, u32 index,
 				unsigned int offset, unsigned int len)
 {
 	zram_slot_lock(zram, index);
-	if (unlikely(!zram->table[index].handle) ||
-			zram_test_flag(zram, index, ZRAM_SAME)) {
+	if (unlikely(!zram_get_handle(zram, index) ||
+			zram_test_flag(zram, index, ZRAM_SAME))) {
 		void *mem;
 
 		zram_slot_unlock(zram, index);
 		mem = kmap_atomic(page);
-		zram_fill_page(mem + offset, len, zram->table[index].element);
+		zram_fill_page(mem + offset, len,
+					zram_get_element(zram, index));
 		kunmap_atomic(mem);
 		return true;
 	}
@@ -472,7 +483,7 @@ static void zram_meta_free(struct zram *zram, u64 disksize)
 
 	/* Free all pages that are still in this zram device */
 	for (index = 0; index < num_pages; index++) {
-		unsigned long handle = zram->table[index].handle;
+		unsigned long handle = zram_get_handle(zram, index);
 		/*
 		 * No memory is allocated for same element filled pages.
 		 * Simply clear same page flag.
@@ -512,7 +523,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
  */
 static void zram_free_page(struct zram *zram, size_t index)
 {
-	unsigned long handle = zram->table[index].handle;
+	unsigned long handle = zram_get_handle(zram, index);
 
 	/*
 	 * No memory is allocated for same element filled pages.
@@ -520,7 +531,7 @@ static void zram_free_page(struct zram *zram, size_t index)
 	 */
 	if (zram_test_flag(zram, index, ZRAM_SAME)) {
 		zram_clear_flag(zram, index, ZRAM_SAME);
-		zram_clear_element(zram, index);
+		zram_set_element(zram, index, 0);
 		atomic64_dec(&zram->stats.same_pages);
 		return;
 	}
@@ -534,7 +545,7 @@ static void zram_free_page(struct zram *zram, size_t index)
 			&zram->stats.compr_data_size);
 	atomic64_dec(&zram->stats.pages_stored);
 
-	zram->table[index].handle = 0;
+	zram_set_handle(zram, index, 0);
 	zram_set_obj_size(zram, index, 0);
 }
 
@@ -549,7 +560,7 @@ static int zram_decompress_page(struct zram *zram, struct page *page, u32 index)
 		return 0;
 
 	zram_slot_lock(zram, index);
-	handle = zram->table[index].handle;
+	handle = zram_get_handle(zram, index);
 	size = zram_get_obj_size(zram, index);
 
 	src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
@@ -715,7 +726,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index)
 	 */
 	zram_slot_lock(zram, index);
 	zram_free_page(zram, index);
-	zram->table[index].handle = handle;
+	zram_set_handle(zram, index, handle);
 	zram_set_obj_size(zram, index, comp_len);
 	zram_slot_unlock(zram, index);
 
-- 
2.7.4