2 files changed, 9 insertions, 12 deletions

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index f1a3c958d84b..011e55d820b1 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -230,6 +230,7 @@ static struct zram_meta *zram_meta_alloc(u64 disksize)
         }
 
         rwlock_init(&meta->tb_lock);
+        mutex_init(&meta->buffer_lock);
         return meta;
 
 free_table:
@@ -412,6 +413,7 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
         struct page *page;
         unsigned char *user_mem, *cmem, *src, *uncmem = NULL;
         struct zram_meta *meta = zram->meta;
+        bool locked = false;
 
         page = bvec->bv_page;
         src = meta->compress_buffer;
@@ -431,6 +433,8 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
                         goto out;
         }
 
+        mutex_lock(&meta->buffer_lock);
+        locked = true;
         user_mem = kmap_atomic(page);
 
         if (is_partial_io(bvec)) {
@@ -457,7 +461,6 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 
         ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen,
                                meta->compress_workmem);
-
         if (!is_partial_io(bvec)) {
                 kunmap_atomic(user_mem);
                 user_mem = NULL;
@@ -514,6 +517,8 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
                 atomic_inc(&zram->stats.good_compress);
 
 out:
+        if (locked)
+                mutex_unlock(&meta->buffer_lock);
         if (is_partial_io(bvec))
                 kfree(uncmem);
 
@@ -527,15 +532,10 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index,
 {
         int ret;
 
-        if (rw == READ) {
-                down_read(&zram->lock);
+        if (rw == READ)
                 ret = zram_bvec_read(zram, bvec, index, offset, bio);
-                up_read(&zram->lock);
-        } else {
-                down_write(&zram->lock);
+        else
                 ret = zram_bvec_write(zram, bvec, index, offset);
-                up_write(&zram->lock);
-        }
 
         return ret;
 }
@@ -808,7 +808,6 @@ static int create_device(struct zram *zram, int device_id)
 {
         int ret = -ENOMEM;
 
-        init_rwsem(&zram->lock);
         init_rwsem(&zram->init_lock);
 
         zram->queue = blk_alloc_queue(GFP_KERNEL);
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index d876300da6c9..ad8aa35bae00 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -88,13 +88,11 @@ struct zram_meta {
         void *compress_buffer;
         struct table *table;
         struct zs_pool *mem_pool;
+        struct mutex buffer_lock; /* protect compress buffers */
 };
 
 struct zram {
         struct zram_meta *meta;
-        struct rw_semaphore lock; /* protect compression buffers,
-                                   * reads and writes
-                                   */
         struct request_queue *queue;
         struct gendisk *disk;
         int init_done;