On Mon, Dec 23, 2019 at 1:49 AM <jgq516@xxxxxxxxx> wrote:
>
> From: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx>
>
> Previously, we call check_and_add_serial when serialization is
> enabled for write IO, but it could allocate and free memory
> back and forth.
>
> Now, let's just get an element from memory pool with the new
> function, then insert node to rb tree if no collision happens.
>
> Signed-off-by: Guoqing Jiang <guoqing.jiang@xxxxxxxxxxxxxxx>
> ---
> drivers/md/raid1.c | 41 ++++++++++++++++++++++-------------------
> 1 file changed, 22 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index 48d553d7989a..cd810e195086 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -56,32 +56,43 @@ static void lower_barrier(struct r1conf *conf, sector_t sector_nr);
> INTERVAL_TREE_DEFINE(struct serial_info, node, sector_t, _subtree_last,
> START, LAST, static inline, raid1_rb);
>
> -static int check_and_add_serial(struct md_rdev *rdev, sector_t lo, sector_t hi)
> +static int check_and_add_serial(struct md_rdev *rdev, struct r1bio *r1_bio,
> + struct serial_info *si, int idx)
> {
> - struct serial_info *si;
> unsigned long flags;
> int ret = 0;
> - struct mddev *mddev = rdev->mddev;
> - int idx = sector_to_idx(lo);
> + sector_t lo = r1_bio->sector;
> + sector_t hi = lo + r1_bio->sectors;
> struct serial_in_rdev *serial = &rdev->serial[idx];
>
> - si = mempool_alloc(mddev->serial_info_pool, GFP_NOIO);
> -
> spin_lock_irqsave(&serial->serial_lock, flags);
> /* collision happened */
> if (raid1_rb_iter_first(&serial->serial_rb, lo, hi))
> ret = -EBUSY;
> - if (!ret) {
> + else {
> si->start = lo;
> si->last = hi;
> raid1_rb_insert(si, &serial->serial_rb);
> - } else
> - mempool_free(si, mddev->serial_info_pool);
> + }
> spin_unlock_irqrestore(&serial->serial_lock, flags);
>
> return ret;
> }
>
> +static void wait_for_serialization(struct md_rdev *rdev, struct r1bio *r1_bio)
> +{
> + struct mddev *mddev = rdev->mddev;
> + struct serial_info *si;
> + int idx = sector_to_idx(r1_bio->sector);
> + struct serial_in_rdev *serial = &rdev->serial[idx];
> +
> + if (WARN_ON(!mddev->serial_info_pool))
> + return;
> + si = mempool_alloc(mddev->serial_info_pool, GFP_NOIO);
> + wait_event(serial->serial_io_wait,
> + check_and_add_serial(rdev, r1_bio, si, idx) == 0);
Are we leaking si when raid1_rb_iter_first() failed?
