[PATCH 6.6.y 3/4] zram: move bd_stat to writeback section

[Sasha Levin <sashal@kernel.org>]

From: Sergey Senozhatsky <senozhatsky@chromium.org>

[ Upstream commit 910bbb441c004050e188dd8da5071054099e592c ]

Move bd_stat function and attribute declaration to
existing CONFIG_WRITEBACK ifdef-sections.

Link: https://lkml.kernel.org/r/20251201094754.4149975-5-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Stevens <stevensd@google.com>
Cc: Minchan Kim <minchan@google.com>
Cc: Richard Chang <richardycc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: dde75313eed0 ("zram: set default primary compressor in zram_destroy_comps()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/block/zram/zram_drv.c | 54 ++++++++++++++++-------------------
 1 file changed, 25 insertions(+), 29 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 64a1136447cf5..6a4870cf6e590 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -364,6 +364,24 @@ static ssize_t idle_store(struct device *dev,
 }
 
 #ifdef CONFIG_ZRAM_WRITEBACK
+#define FOUR_K(x) ((x) * (1 << (PAGE_SHIFT - 12)))
+static ssize_t bd_stat_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct zram *zram = dev_to_zram(dev);
+	ssize_t ret;
+
+	down_read(&zram->init_lock);
+	ret = scnprintf(buf, PAGE_SIZE,
+		"%8llu %8llu %8llu\n",
+			FOUR_K((u64)atomic64_read(&zram->stats.bd_count)),
+			FOUR_K((u64)atomic64_read(&zram->stats.bd_reads)),
+			FOUR_K((u64)atomic64_read(&zram->stats.bd_writes)));
+	up_read(&zram->init_lock);
+
+	return ret;
+}
+
 static ssize_t writeback_limit_enable_store(struct device *dev,
 					    struct device_attribute *attr,
 					    const char *buf, size_t len)
@@ -1200,27 +1218,6 @@ static ssize_t mm_stat_show(struct device *dev,
 
 	return ret;
 }
-
-#ifdef CONFIG_ZRAM_WRITEBACK
-#define FOUR_K(x) ((x) * (1 << (PAGE_SHIFT - 12)))
-static ssize_t bd_stat_show(struct device *dev,
-		struct device_attribute *attr, char *buf)
-{
-	struct zram *zram = dev_to_zram(dev);
-	ssize_t ret;
-
-	down_read(&zram->init_lock);
-	ret = scnprintf(buf, PAGE_SIZE,
-		"%8llu %8llu %8llu\n",
-			FOUR_K((u64)atomic64_read(&zram->stats.bd_count)),
-			FOUR_K((u64)atomic64_read(&zram->stats.bd_reads)),
-			FOUR_K((u64)atomic64_read(&zram->stats.bd_writes)));
-	up_read(&zram->init_lock);
-
-	return ret;
-}
-#endif
-
 static ssize_t debug_stat_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
@@ -1241,9 +1238,6 @@ static ssize_t debug_stat_show(struct device *dev,
 
 static DEVICE_ATTR_RO(io_stat);
 static DEVICE_ATTR_RO(mm_stat);
-#ifdef CONFIG_ZRAM_WRITEBACK
-static DEVICE_ATTR_RO(bd_stat);
-#endif
 static DEVICE_ATTR_RO(debug_stat);
 
 static void zram_meta_free(struct zram *zram, u64 disksize)
@@ -2014,6 +2008,7 @@ static void zram_slot_free_notify(struct block_device *bdev,
 	zram_slot_unlock(zram, index);
 }
 
+#define zram_comp_params_reset(_zram) ((void)(_zram))
 static void zram_destroy_comps(struct zram *zram)
 {
 	u32 prio;
@@ -2034,11 +2029,14 @@ static void zram_destroy_comps(struct zram *zram)
 			kfree(zram->comp_algs[prio]);
 		zram->comp_algs[prio] = NULL;
 	}
+
+	zram_comp_params_reset(zram);
 }
+#undef zram_comp_params_reset
 
 static void zram_reset_device(struct zram *zram)
 {
-	down_write(&zram->init_lock);
+	guard(rwsem_write)(&zram->init_lock);
 
 	zram->limit_pages = 0;
 
@@ -2053,7 +2051,6 @@ static void zram_reset_device(struct zram *zram)
 	reset_bdev(zram);
 
 	comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor);
-	up_write(&zram->init_lock);
 }
 
 static ssize_t disksize_store(struct device *dev,
@@ -2180,6 +2177,7 @@ static DEVICE_ATTR_WO(idle);
 static DEVICE_ATTR_RW(max_comp_streams);
 static DEVICE_ATTR_RW(comp_algorithm);
 #ifdef CONFIG_ZRAM_WRITEBACK
+static DEVICE_ATTR_RO(bd_stat);
 static DEVICE_ATTR_RW(backing_dev);
 static DEVICE_ATTR_WO(writeback);
 static DEVICE_ATTR_RW(writeback_limit);
@@ -2201,6 +2199,7 @@ static struct attribute *zram_disk_attrs[] = {
 	&dev_attr_max_comp_streams.attr,
 	&dev_attr_comp_algorithm.attr,
 #ifdef CONFIG_ZRAM_WRITEBACK
+	&dev_attr_bd_stat.attr,
 	&dev_attr_backing_dev.attr,
 	&dev_attr_writeback.attr,
 	&dev_attr_writeback_limit.attr,
@@ -2208,9 +2207,6 @@ static struct attribute *zram_disk_attrs[] = {
 #endif
 	&dev_attr_io_stat.attr,
 	&dev_attr_mm_stat.attr,
-#ifdef CONFIG_ZRAM_WRITEBACK
-	&dev_attr_bd_stat.attr,
-#endif
 	&dev_attr_debug_stat.attr,
 #ifdef CONFIG_ZRAM_MULTI_COMP
 	&dev_attr_recomp_algorithm.attr,
-- 
2.53.0