From: Huang, Tao <huangtao@rock-chips.com>
Date: Tue, 2 Jun 2015 03:25:10 +0000 (+0800)
Subject: Revert "zram: don't grab mutex in zram_slot_free_noity"
X-Git-Tag: firefly_0821_release~4092
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=668e3ed51ff0211bd5fdf8915fde9ccd27eb4e69;p=firefly-linux-kernel-4.4.55.git

Revert "zram: don't grab mutex in zram_slot_free_noity"

This reverts commit 66db73c14bd16d8ad05ecb80e6bf6050d8828467.
---

diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index daaa07193199..a333d44d0cff 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -278,14 +278,6 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 		goto out;
 	}
 
-	/*
-	 * zram_slot_free_notify could miss free so that let's
-	 * double check.
-	 */
-	if (unlikely(meta->table[index].handle ||
-			zram_test_flag(meta, index, ZRAM_ZERO)))
-		zram_free_page(zram, index);
-
 	ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen,
 			       meta->compress_workmem);
 
@@ -343,20 +335,6 @@ out:
 	return ret;
 }
 
-static void handle_pending_slot_free(struct zram *zram)
-{
-	struct zram_slot_free *free_rq;
-
-	spin_lock(&zram->slot_free_lock);
-	while (zram->slot_free_rq) {
-		free_rq = zram->slot_free_rq;
-		zram->slot_free_rq = free_rq->next;
-		zram_free_page(zram, free_rq->index);
-		kfree(free_rq);
-	}
-	spin_unlock(&zram->slot_free_lock);
-}
-
 static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
 			int offset, struct bio *bio, int rw)
 {
@@ -364,12 +342,10 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
 
 	if (rw == READ) {
 		down_read(&zram->lock);
-		handle_pending_slot_free(zram);
 		ret = zram_bvec_read(zram, bvec, index, offset, bio);
 		up_read(&zram->lock);
 	} else {
 		down_write(&zram->lock);
-		handle_pending_slot_free(zram);
 		ret = zram_bvec_write(zram, bvec, index, offset);
 		up_write(&zram->lock);
 	}
@@ -520,8 +496,6 @@ static void __zram_reset_device(struct zram *zram)
 
 void zram_reset_device(struct zram *zram)
 {
-	flush_work(&zram->free_work);
-
 	down_write(&zram->init_lock);
 	__zram_reset_device(zram);
 	up_write(&zram->init_lock);
@@ -607,40 +581,16 @@ void zram_init_device(struct zram *zram, struct zram_meta *meta)
 	pr_debug("Initialization done!\n");
 }
 
-static void zram_slot_free(struct work_struct *work)
-{
-	struct zram *zram;
-
-	zram = container_of(work, struct zram, free_work);
-	down_write(&zram->lock);
-	handle_pending_slot_free(zram);
-	up_write(&zram->lock);
-}
-
-static void add_slot_free(struct zram *zram, struct zram_slot_free *free_rq)
-{
-	spin_lock(&zram->slot_free_lock);
-	free_rq->next = zram->slot_free_rq;
-	zram->slot_free_rq = free_rq;
-	spin_unlock(&zram->slot_free_lock);
-}
-
 static void zram_slot_free_notify(struct block_device *bdev,
 				unsigned long index)
 {
 	struct zram *zram;
-	struct zram_slot_free *free_rq;
 
 	zram = bdev->bd_disk->private_data;
+	down_write(&zram->lock);
+	zram_free_page(zram, index);
+	up_write(&zram->lock);
 	zram_stat64_inc(zram, &zram->stats.notify_free);
-
-	free_rq = kmalloc(sizeof(struct zram_slot_free), GFP_ATOMIC);
-	if (!free_rq)
-		return;
-
-	free_rq->index = index;
-	add_slot_free(zram, free_rq);
-	schedule_work(&zram->free_work);
 }
 
 static const struct block_device_operations zram_devops = {
@@ -656,10 +606,6 @@ static int create_device(struct zram *zram, int device_id)
 	init_rwsem(&zram->init_lock);
 	spin_lock_init(&zram->stat64_lock);
 
-	INIT_WORK(&zram->free_work, zram_slot_free);
-	spin_lock_init(&zram->slot_free_lock);
-	zram->slot_free_rq = NULL;
-
 	zram->queue = blk_alloc_queue(GFP_KERNEL);
 	if (!zram->queue) {
 		pr_err("Error allocating disk queue for device %d\n",
diff --git a/drivers/staging/zram/zram_drv.h b/drivers/staging/zram/zram_drv.h
index ece3524ea403..d542eee81357 100644
--- a/drivers/staging/zram/zram_drv.h
+++ b/drivers/staging/zram/zram_drv.h
@@ -90,21 +90,12 @@ struct zram_meta {
 	struct zs_pool *mem_pool;
 };
 
-struct zram_slot_free {
-	unsigned long index;
-	struct zram_slot_free *next;
-};
-
 struct zram {
 	struct zram_meta *meta;
 	spinlock_t stat64_lock;	/* protect 64-bit stats */
 	struct rw_semaphore lock; /* protect compression buffers, table,
 				   * 32bit stat counters against concurrent
 				   * notifications, reads and writes */
-
-	struct work_struct free_work;  /* handle pending free request */
-	struct zram_slot_free *slot_free_rq; /* list head of free request */
-
 	struct request_queue *queue;
 	struct gendisk *disk;
 	int init_done;
@@ -115,7 +106,6 @@ struct zram {
 	 * we can store in a disk.
 	 */
 	u64 disksize;	/* bytes */
-	spinlock_t slot_free_lock;
 
 	struct zram_stats stats;
 };