[PATCH 08/10] Some cleanups

[Nitin Gupta <ngupta@vflare.org>]

 - xvmalloc: Remove unnecessary stat_{inc,dec} and increment
   pages_stored directly
 - xvmalloc: Initialize pointers with NULL instead of 0
 - zram: Remove verbose message when use sets insane disksize
 - zram: Mark some messages as pr_debug
 - zram: Refine some comments

Signed-off-by: Nitin Gupta <ngupta@vflare.org>
---
 drivers/staging/zram/xvmalloc.c |   22 ++++-------------
 drivers/staging/zram/zram_drv.c |   49 +++++++++++++-------------------------
 drivers/staging/zram/zram_drv.h |   26 ++++----------------
 3 files changed, 28 insertions(+), 69 deletions(-)

diff --git a/drivers/staging/zram/xvmalloc.c b/drivers/staging/zram/xvmalloc.c
index 3fdbb8a..6268f65 100644
--- a/drivers/staging/zram/xvmalloc.c
+++ b/drivers/staging/zram/xvmalloc.c
@@ -20,16 +20,6 @@
 #include "xvmalloc.h"
 #include "xvmalloc_int.h"
 
-static void stat_inc(u64 *value)
-{
-	*value = *value + 1;
-}
-
-static void stat_dec(u64 *value)
-{
-	*value = *value - 1;
-}
-
 static int test_flag(struct block_header *block, enum blockflags flag)
 {
 	return block->prev & BIT(flag);
@@ -187,7 +177,7 @@ static void insert_block(struct xv_pool *pool, struct page *page, u32 offset,
 	slindex = get_index_for_insert(block->size);
 	flindex = slindex / BITS_PER_LONG;
 
-	block->link.prev_page = 0;
+	block->link.prev_page = NULL;
 	block->link.prev_offset = 0;
 	block->link.next_page = pool->freelist[slindex].page;
 	block->link.next_offset = pool->freelist[slindex].offset;
@@ -217,7 +207,7 @@ static void remove_block_head(struct xv_pool *pool,
 
 	pool->freelist[slindex].page = block->link.next_page;
 	pool->freelist[slindex].offset = block->link.next_offset;
-	block->link.prev_page = 0;
+	block->link.prev_page = NULL;
 	block->link.prev_offset = 0;
 
 	if (!pool->freelist[slindex].page) {
@@ -232,7 +222,7 @@ static void remove_block_head(struct xv_pool *pool,
 		 */
 		tmpblock = get_ptr_atomic(pool->freelist[slindex].page,
 				pool->freelist[slindex].offset, KM_USER1);
-		tmpblock->link.prev_page = 0;
+		tmpblock->link.prev_page = NULL;
 		tmpblock->link.prev_offset = 0;
 		put_ptr_atomic(tmpblock, KM_USER1);
 	}
@@ -284,7 +274,7 @@ static int grow_pool(struct xv_pool *pool, gfp_t flags)
 	if (unlikely(!page))
 		return -ENOMEM;
 
-	stat_inc(&pool->total_pages);
+	pool->total_pages++;
 
 	spin_lock(&pool->lock);
 	block = get_ptr_atomic(page, 0, KM_USER0);
@@ -361,8 +351,6 @@ int xv_malloc(struct xv_pool *pool, u32 size, struct page **page,
 
 	if (!*page) {
 		spin_unlock(&pool->lock);
-		if (flags & GFP_NOWAIT)
-			return -ENOMEM;
 		error = grow_pool(pool, flags);
 		if (unlikely(error))
 			return error;
@@ -472,7 +460,7 @@ void xv_free(struct xv_pool *pool, struct page *page, u32 offset)
 		spin_unlock(&pool->lock);
 
 		__free_page(page);
-		stat_dec(&pool->total_pages);
+		pool->total_pages--;
 		return;
 	}
 
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index 0f9785f..42aa271 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -9,7 +9,7 @@
  * Released under the terms of 3-clause BSD License
  * Released under the terms of GNU General Public License Version 2.0
  *
- * Project home: http://compcache.googlecode.com
+ * Project home: http://compcache.googlecode.com/
  */
 
 #define KMSG_COMPONENT "zram"
@@ -130,33 +130,15 @@ static void zram_insert_obj(struct zram *zram, u32 index, struct page *page,
 	zram->table[index].addr = addr;
 }
 
-static void zram_set_disksize(struct zram *zram, size_t totalram_bytes)
+static u64 zram_default_disksize(void)
 {
-	if (!zram->disksize) {
-		pr_info(
-		"disk size not provided. You can use disksize_kb module "
-		"param to specify size.\nUsing default: (%u%% of RAM).\n",
-		default_disksize_perc_ram
-		);
-		zram->disksize = default_disksize_perc_ram *
-					(totalram_bytes / 100);
-	}
+	u64 disksize;
 
-	if (zram->disksize > 2 * (totalram_bytes)) {
-		pr_info(
-		"There is little point creating a zram of greater than "
-		"twice the size of memory since we expect a 2:1 compression "
-		"ratio. Note that zram uses about 0.1%% of the size of "
-		"the disk when not in use so a huge zram is "
-		"wasteful.\n"
-		"\tMemory Size: %zu kB\n"
-		"\tSize you selected: %llu kB\n"
-		"Continuing anyway ...\n",
-		totalram_bytes >> 10, zram->disksize
-		);
-	}
+	disksize = default_disksize_perc_ram *
+			(totalram_pages / 100);
+	disksize = (disksize << PAGE_SHIFT) & PAGE_MASK;
 
-	zram->disksize &= PAGE_MASK;
+	return disksize;
 }
 
 static void zram_free_page(struct zram *zram, size_t index)
@@ -459,7 +441,7 @@ static int zram_make_request(struct request_queue *queue, struct bio *bio)
 	int ret = 0;
 	struct zram *zram = queue->queuedata;
 
-	if (!valid_io_request(zram, bio)) {
+	if (unlikely(!valid_io_request(zram, bio))) {
 		zram_inc_stat(zram, ZRAM_STAT_INVALID_IO);
 		bio_io_error(bio);
 		return 0;
@@ -504,7 +486,7 @@ void zram_reset_device(struct zram *zram)
 	/* Reset stats */
 	memset(&zram->stats, 0, sizeof(zram->stats));
 
-	zram->disksize = 0;
+	zram->disksize = zram_default_disksize();
 	mutex_unlock(&zram->init_lock);
 }
 
@@ -520,7 +502,8 @@ int zram_init_device(struct zram *zram)
 		return 0;
 	}
 
-	zram_set_disksize(zram, totalram_pages << PAGE_SHIFT);
+	if (!zram->disksize)
+		zram->disksize = zram_default_disksize();
 
 	num_pages = zram->disksize >> PAGE_SHIFT;
 	zram->table = vmalloc(num_pages * sizeof(*zram->table));
@@ -566,7 +549,8 @@ fail:
 	return ret;
 }
 
-void zram_slot_free_notify(struct block_device *bdev, unsigned long index)
+static void zram_slot_free_notify(struct block_device *bdev,
+				unsigned long index)
 {
 	struct zram *zram;
 
@@ -614,8 +598,9 @@ static int create_device(struct zram *zram, int device_id)
 	zram->disk->private_data = zram;
 	snprintf(zram->disk->disk_name, 16, "zram%d", device_id);
 
-	/* Actual capacity set using syfs (/sys/block/zram<id>/disksize */
-	set_capacity(zram->disk, 0);
+	/* Custom size can be set using syfs (/sys/block/zram<id>/disksize) */
+	zram->disksize = zram_default_disksize();
+	set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
 
 	/*
 	 * To ensure that we always get PAGE_SIZE aligned
@@ -739,7 +724,7 @@ static int __init zram_init(void)
 	}
 
 	/* Allocate the device array and initialize each one */
-	pr_info("Creating %u devices ...\n", num_devices);
+	pr_debug("Creating %u devices ...\n", num_devices);
 	devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL);
 	if (!devices) {
 		ret = -ENOMEM;
diff --git a/drivers/staging/zram/zram_drv.h b/drivers/staging/zram/zram_drv.h
index bcc51ea..2cf36db 100644
--- a/drivers/staging/zram/zram_drv.h
+++ b/drivers/staging/zram/zram_drv.h
@@ -9,7 +9,7 @@
  * Released under the terms of 3-clause BSD License
  * Released under the terms of GNU General Public License Version 2.0
  *
- * Project home: http://compcache.googlecode.com
+ * Project home: http://compcache.googlecode.com/
  */
 
 #ifndef _ZRAM_DRV_H_
@@ -26,18 +26,6 @@
  */
 static const unsigned max_num_devices = 32;
 
-/*
- * Stored at beginning of each compressed object.
- *
- * It stores back-reference to table entry which points to this
- * object. This is required to support memory defragmentation.
- */
-struct zobj_header {
-#if 0
-	u32 table_idx;
-#endif
-};
-
 /*-- Configurable parameters */
 
 /* Default zram disk size: 25% of total RAM */
@@ -50,8 +38,7 @@ static const unsigned default_disksize_perc_ram = 25;
 static const unsigned max_zpage_size = PAGE_SIZE / 8 * 7;
 
 /*
- * NOTE: max_zpage_size must be less than or equal to:
- *   XV_MAX_ALLOC_SIZE - sizeof(struct zobj_header)
+ * NOTE: max_zpage_size must be less than or equal to XV_MAX_ALLOC_SIZE
  * otherwise, xv_malloc() would always return failure.
  */
 
@@ -92,16 +79,15 @@ struct zram {
 	struct table *table;
 	struct request_queue *queue;
 	struct gendisk *disk;
-	int init_done;
+	unsigned int init_done;
 	/* Prevent concurrent execution of device init and reset */
 	struct mutex init_lock;
 	/*
 	 * This is the limit on amount of *uncompressed* worth of data
-	 * we can store in a disk.
+	 * we can store in a disk (in bytes).
 	 */
-	u64 disksize;	/* bytes */
-
-	struct zram_stats_cpu *stats;
+	u64 disksize;
+	struct zram_stats_cpu *stats;	/* percpu stats */
 };
 
 extern struct zram *devices;
-- 
1.7.2.1