1 files changed, 24 insertions, 14 deletions

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index e551433cd107..7c74d8cba44f 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -329,8 +329,8 @@ static ssize_t idle_store(struct device *dev,
 
 	if (!sysfs_streq(buf, "all")) {
 		/*
-		 * If it did not parse as 'all' try to treat it as an integer when
-		 * we have memory tracking enabled.
+		 * If it did not parse as 'all' try to treat it as an integer
+		 * when we have memory tracking enabled.
 		 */
 		u64 age_sec;
 
@@ -345,7 +345,10 @@ static ssize_t idle_store(struct device *dev,
 	if (!init_done(zram))
 		goto out_unlock;
 
-	/* A cutoff_time of 0 marks everything as idle, this is the "all" behavior */
+	/*
+	 * A cutoff_time of 0 marks everything as idle, this is the
+	 * "all" behavior.
+	 */
 	mark_idle(zram, cutoff_time);
 	rv = len;
 
@@ -1410,9 +1413,19 @@ compress_again:
 		handle = zs_malloc(zram->mem_pool, comp_len,
 				GFP_NOIO | __GFP_HIGHMEM |
 				__GFP_MOVABLE);
-		if (!IS_ERR((void *)handle))
+		if (IS_ERR((void *)handle))
+			return PTR_ERR((void *)handle);
+
+		if (comp_len != PAGE_SIZE)
 			goto compress_again;
-		return PTR_ERR((void *)handle);
+		/*
+		 * If the page is not compressible, you need to acquire the
+		 * lock and execute the code below. The zcomp_stream_get()
+		 * call is needed to disable the cpu hotplug and grab the
+		 * zstrm buffer back. It is necessary that the dereferencing
+		 * of the zstrm variable below occurs correctly.
+		 */
+		zstrm = zcomp_stream_get(zram->comp);
 	}
 
 	alloced_pages = zs_get_total_pages(zram->mem_pool);
@@ -1710,9 +1723,6 @@ out:
 
 static void zram_reset_device(struct zram *zram)
 {
-	struct zcomp *comp;
-	u64 disksize;
-
 	down_write(&zram->init_lock);
 
 	zram->limit_pages = 0;
@@ -1722,17 +1732,15 @@ static void zram_reset_device(struct zram *zram)
 		return;
 	}
 
-	comp = zram->comp;
-	disksize = zram->disksize;
-	zram->disksize = 0;
-
 	set_capacity_and_notify(zram->disk, 0);
 	part_stat_set_all(zram->disk->part0, 0);
 
 	/* I/O operation under all of CPU are done so let's free */
-	zram_meta_free(zram, disksize);
+	zram_meta_free(zram, zram->disksize);
+	zram->disksize = 0;
 	memset(&zram->stats, 0, sizeof(zram->stats));
-	zcomp_destroy(comp);
+	zcomp_destroy(zram->comp);
+	zram->comp = NULL;
 	reset_bdev(zram);
 
 	up_write(&zram->init_lock);
@@ -2126,6 +2134,8 @@ static int __init zram_init(void)
 {
 	int ret;
 
+	BUILD_BUG_ON(__NR_ZRAM_PAGEFLAGS > BITS_PER_LONG);
+
 	ret = cpuhp_setup_state_multi(CPUHP_ZCOMP_PREPARE, "block/zram:prepare",
 				      zcomp_cpu_up_prepare, zcomp_cpu_dead);
 	if (ret < 0)