On 02/25/2014 02:08 AM, Minchan Kim wrote:
> From: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
>
> 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.
>
> [minc...@kernel.org]: handled zram->meta alloc fail case.
> Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
> Signed-off-by: Minchan Kim <minc...@kernel.org>
Acked-by: Jerome Marchand <jmarc...@redhat.com>
> ---
> drivers/block/zram/zram_drv.c | 25 +++++++++----------------
> 1 file changed, 9 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index 21aee3edcb25..9baac5b76bfe 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -533,40 +533,32 @@ 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)
> {
> u64 disksize;
> - struct zram_meta *meta;
> struct zram *zram = dev_to_zram(dev);
>
> disksize = memparse(buf, NULL);
> if (!disksize)
> return -EINVAL;
>
> - disksize = PAGE_ALIGN(disksize);
> - 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);
> pr_info("Cannot change disksize for initialized device\n");
> return -EBUSY;
> }
>
> + disksize = PAGE_ALIGN(disksize);
> + zram->meta = zram_meta_alloc(disksize);
> + if (!zram->meta) {
> + up_write(&zram->init_lock);
> + return -ENOMEM;
> + }
> +
> 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 +768,8 @@ 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.
>
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