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

[Su Yue <l@damenly.org>]

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

> On 6/19/25 08:56, Su Yue wrote:
>> On Wed 18 Jun 2025 at 19:41, Wang Jinchao 
>> <wangjinchao600@gmail.com> 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@gmail.com>
>>> ---
>>>  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;