zram: delete zram_init_device()

allocate new `zram_meta' in disksize_store() only for uninitialised zram
device, saving a number of allocations and deallocations in case if
disksize_store() was called on currently used device.  at the same time
zram_meta stack variable is not necessary, because we can set ->meta
directly.  there is also no need in setting QUEUE_FLAG_NONROT queue on
every disksize_store(), set it once during device creation.

[minchan@kernel.org: handle zram->meta alloc fail case]
[minchan@kernel.org: prevent lockdep spew of init_lock]
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 21aee3edcb25c1611dab5df056b7ae4e5b51b81e..76ba67673a901d4cd35ca4798d00f6bf138d6b7c 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -533,14 +533,6 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity)
        up_write(&zram->init_lock);
 }
 
-static void zram_init_device(struct zram *zram, struct zram_meta *meta)
-{
-       /* zram devices sort of resembles non-rotational disks */
-       queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);
-       zram->meta = meta;
-       pr_debug("Initialization done!\n");
-}
-
 static ssize_t disksize_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t len)
 {
@@ -556,17 +548,18 @@ static ssize_t disksize_store(struct device *dev,
        meta = zram_meta_alloc(disksize);
        if (!meta)
                return -ENOMEM;
+
        down_write(&zram->init_lock);
        if (init_done(zram)) {
-               up_write(&zram->init_lock);
                zram_meta_free(meta);
+               up_write(&zram->init_lock);
                pr_info("Cannot change disksize for initialized device\n");
                return -EBUSY;
        }
 
+       zram->meta = meta;
        zram->disksize = disksize;
        set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
-       zram_init_device(zram, meta);
        up_write(&zram->init_lock);
 
        return len;
@@ -776,7 +769,8 @@ static int create_device(struct zram *zram, int device_id)
 
        /* Actual capacity set using syfs (/sys/block/zram<id>/disksize */
        set_capacity(zram->disk, 0);
-
+       /* zram devices sort of resembles non-rotational disks */
+       queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zram->disk->queue);
        /*
         * To ensure that we always get PAGE_SIZE aligned
         * and n*PAGE_SIZED sized I/O requests.