Re: [PATCH] md/raid1: change r1conf->r1bio_pool to a pointer type

[Su Yue <l@xxxxxxxxxxx>]

On Thu 19 Jun 2025 at 10:01, Wang Jinchao 
<wangjinchao600@xxxxxxxxx> wrote:

> On 6/19/25 08:56, Su Yue wrote:
> > On Wed 18 Jun 2025 at 19:41, Wang Jinchao 
> > <wangjinchao600@xxxxxxxxx> wrote:
> >
> > > In raid1_reshape(), newpool is a stack variable.
> > > mempool_init() initializes newpool->wait with the stack 
> > > address.
> > > After assigning newpool to conf->r1bio_pool, the wait queue
> > > need to be reinitialized, which is not ideal.
> > >
> > > Change raid1_conf->r1bio_pool to a pointer type and
> > > replace mempool_init() with mempool_create() to
> > > avoid referencing a stack-based wait queue.
> > >
> > > Signed-off-by: Wang Jinchao <wangjinchao600@xxxxxxxxx>
> > > ---
> > >  drivers/md/raid1.c | 31 +++++++++++++------------------
> > >  drivers/md/raid1.h |  2 +-
> > >  2 files changed, 14 insertions(+), 19 deletions(-)
> > >
> > > diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> > > index fd4ce2a4136f..4d4833915b5f 100644
> > > --- a/drivers/md/raid1.c
> > > +++ b/drivers/md/raid1.c
> > > @@ -255,7 +255,7 @@ static void free_r1bio(struct r1bio 
> > > *r1_bio)
> > >      struct r1conf *conf = r1_bio->mddev->private;
> > >
> > >      put_all_bios(conf, r1_bio);
> > > -    mempool_free(r1_bio, &conf->r1bio_pool);
> > > +    mempool_free(r1_bio, conf->r1bio_pool);
> > >  }
> > >
> > >  static void put_buf(struct r1bio *r1_bio)
> > > @@ -1305,7 +1305,7 @@ alloc_r1bio(struct mddev *mddev, struct 
> > > bio *bio)
> > >      struct r1conf *conf = mddev->private;
> > >      struct r1bio *r1_bio;
> > >
> > > -    r1_bio = mempool_alloc(&conf->r1bio_pool, GFP_NOIO);
> > > +    r1_bio = mempool_alloc(conf->r1bio_pool, GFP_NOIO);
> > >      /* Ensure no bio records IO_BLOCKED */
> > >      memset(r1_bio->bios, 0, conf->raid_disks * 
> > >  sizeof(r1_bio-  >bios[0]));
> > >      init_r1bio(r1_bio, mddev, bio);
> > > @@ -3124,9 +3124,9 @@ static struct r1conf *setup_conf(struct 
> > > mddev *mddev)
> > >      if (!conf->poolinfo)
> > >          goto abort;
> > >      conf->poolinfo->raid_disks = mddev->raid_disks * 2;
> > > -    err = mempool_init(&conf->r1bio_pool, NR_RAID_BIOS, 
> > > r1bio_pool_alloc,
> > > -               rbio_pool_free, conf->poolinfo);
> > > -    if (err)
> > > +    conf->r1bio_pool = mempool_create(NR_RAID_BIOS, 
> > > r1bio_pool_alloc,
> > > +                      rbio_pool_free, conf->poolinfo);
> > > +    if (!conf->r1bio_pool)
> > err should be set to -ENOMEM.
> At the beginning of the function, err is initialized to -ENOMEM.
Alright...

--
Su
> > -- Su
> >
> > >          goto abort;
> > >
> > >      err = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
> > > @@ -3197,7 +3197,7 @@ static struct r1conf *setup_conf(struct 
> > > mddev *mddev)
> > >
> > >   abort:
> > >      if (conf) {
> > > -        mempool_exit(&conf->r1bio_pool);
> > > +        mempool_destroy(conf->r1bio_pool);
> > >          kfree(conf->mirrors);
> > >          safe_put_page(conf->tmppage);
> > >          kfree(conf->poolinfo);
> > > @@ -3310,7 +3310,7 @@ static void raid1_free(struct mddev 
> > > *mddev, void *priv)
> > >  {
> > >      struct r1conf *conf = priv;
> > >
> > > -    mempool_exit(&conf->r1bio_pool);
> > > +    mempool_destroy(conf->r1bio_pool);
> > >      kfree(conf->mirrors);
> > >      safe_put_page(conf->tmppage);
> > >      kfree(conf->poolinfo);
> > > @@ -3366,17 +3366,13 @@ static int raid1_reshape(struct mddev 
> > > *mddev)
> > >       * At the same time, we "pack" the devices so that all 
> > > the  missing
> > >       * devices have the higher raid_disk numbers.
> > >       */
> > > -    mempool_t newpool, oldpool;
> > > +    mempool_t *newpool, *oldpool;
> > >      struct pool_info *newpoolinfo;
> > >      struct raid1_info *newmirrors;
> > >      struct r1conf *conf = mddev->private;
> > >      int cnt, raid_disks;
> > >      unsigned long flags;
> > >      int d, d2;
> > > -    int ret;
> > > -
> > > -    memset(&newpool, 0, sizeof(newpool));
> > > -    memset(&oldpool, 0, sizeof(oldpool));
> > >
> > >      /* Cannot change chunk_size, layout, or level */
> > >      if (mddev->chunk_sectors != mddev->new_chunk_sectors ||
> > > @@ -3408,18 +3404,18 @@ static int raid1_reshape(struct mddev 
> > > *mddev)
> > >      newpoolinfo->mddev = mddev;
> > >      newpoolinfo->raid_disks = raid_disks * 2;
> > >
> > > -    ret = mempool_init(&newpool, NR_RAID_BIOS, 
> > > r1bio_pool_alloc,
> > > +    newpool = mempool_create(NR_RAID_BIOS, r1bio_pool_alloc,
> > >                 rbio_pool_free, newpoolinfo);
> > > -    if (ret) {
> > > +    if (!newpool) {
> > >          kfree(newpoolinfo);
> > > -        return ret;
> > > +        return -ENOMEM;
> > >      }
> > >      newmirrors = kzalloc(array3_size(sizeof(struct 
> > > raid1_info),
> > >                       raid_disks, 2),
> > >                   GFP_KERNEL);
> > >      if (!newmirrors) {
> > >          kfree(newpoolinfo);
> > > -        mempool_exit(&newpool);
> > > +        mempool_destroy(newpool);
> > >          return -ENOMEM;
> > >      }
> > >
> > > @@ -3428,7 +3424,6 @@ static int raid1_reshape(struct mddev 
> > > *mddev)
> > >      /* ok, everything is stopped */
> > >      oldpool = conf->r1bio_pool;
> > >      conf->r1bio_pool = newpool;
> > > -    init_waitqueue_head(&conf->r1bio_pool.wait);
> > >
> > >      for (d = d2 = 0; d < conf->raid_disks; d++) {
> > >          struct md_rdev *rdev = conf->mirrors[d].rdev;
> > > @@ -3460,7 +3455,7 @@ static int raid1_reshape(struct mddev 
> > > *mddev)
> > >      set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
> > >      md_wakeup_thread(mddev->thread);
> > >
> > > -    mempool_exit(&oldpool);
> > > +    mempool_destroy(oldpool);
> > >      return 0;
> > >  }
> > >
> > > diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h
> > > index 33f318fcc268..652c347b1a70 100644
> > > --- a/drivers/md/raid1.h
> > > +++ b/drivers/md/raid1.h
> > > @@ -118,7 +118,7 @@ struct r1conf {
> > >       * mempools - it changes when the array grows or shrinks
> > >       */
> > >      struct pool_info    *poolinfo;
> > > -    mempool_t        r1bio_pool;
> > > +    mempool_t        *r1bio_pool;
> > >      mempool_t        r1buf_pool;
> > >
> > >      struct bio_set        bio_split;