[PATCH] zram: use writer semaphores in device attributes store

[Geliang Tang]

Since the device attributes store provides write access. This patch uses
down_write()/up_write() instead of down_read()/up_read() in
mem_used_max_store() and compact_store().

Signed-off-by: Geliang Tang <geliangt...@gmail.com>
---
 drivers/block/zram/zram_drv.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 7454cf1..cfed743 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -293,13 +293,13 @@ static ssize_t mem_used_max_store(struct device *dev,
        if (err || val != 0)
                return -EINVAL;
 
-       down_read(&zram->init_lock);
+       down_write(&zram->init_lock);
        if (init_done(zram)) {
                struct zram_meta *meta = zram->meta;
                atomic_long_set(&zram->stats.max_used_pages,
                                zs_get_total_pages(meta->mem_pool));
        }
-       up_read(&zram->init_lock);
+       up_write(&zram->init_lock);
 
        return len;
 }
@@ -372,15 +372,15 @@ static ssize_t compact_store(struct device *dev,
        struct zram *zram = dev_to_zram(dev);
        struct zram_meta *meta;
 
-       down_read(&zram->init_lock);
+       down_write(&zram->init_lock);
        if (!init_done(zram)) {
-               up_read(&zram->init_lock);
+               up_write(&zram->init_lock);
                return -EINVAL;
        }
 
        meta = zram->meta;
        zs_compact(meta->mem_pool);
-       up_read(&zram->init_lock);
+       up_write(&zram->init_lock);
 
        return len;
 }
-- 
1.9.1