Re: [PATCH v11 2/9] block: Add copy offload support infrastructure

[Nitesh Shetty]

On 23/05/30 01:29PM, Maurizio Lombardi wrote:
> po 22. 5. 2023 v 13:17 odesílatel Nitesh Shetty <nj.shetty@xxxxxxxxxxx> napsal:
> > +static int __blkdev_copy_offload(struct block_device *bdev_in, loff_t pos_in,
> > +               struct block_device *bdev_out, loff_t pos_out, size_t len,
> > +               cio_iodone_t endio, void *private, gfp_t gfp_mask)
> > +{
> > +       struct cio *cio;
> > +       struct copy_ctx *ctx;
> > +       struct bio *read_bio, *write_bio;
> > +       struct page *token;
> > +       sector_t copy_len;
> > +       sector_t rem, max_copy_len;
> > +
> > +       cio = kzalloc(sizeof(struct cio), GFP_KERNEL);
> > +       if (!cio)
> > +               return -ENOMEM;
> > +       atomic_set(&cio->refcount, 0);
> > +       cio->waiter = current;
> > +       cio->endio = endio;
> > +       cio->private = private;
> > +
> > +       max_copy_len = min(bdev_max_copy_sectors(bdev_in),
> > +                       bdev_max_copy_sectors(bdev_out)) << SECTOR_SHIFT;
> > +
> > +       cio->pos_in = pos_in;
> > +       cio->pos_out = pos_out;
> > +       /* If there is a error, comp_len will be set to least successfully
> > +        * completed copied length
> > +        */
> > +       cio->comp_len = len;
> > +       for (rem = len; rem > 0; rem -= copy_len) {
> > +               copy_len = min(rem, max_copy_len);
> > +
> > +               token = alloc_page(gfp_mask);
> > +               if (unlikely(!token))
> > +                       goto err_token;
>
> [...]
>
> > +err_token:
> > +       cio->comp_len = min_t(sector_t, cio->comp_len, (len - rem));
> > +       if (!atomic_read(&cio->refcount))
> > +               return -ENOMEM;
> > +       /* Wait for submitted IOs to complete */
> > +       return blkdev_copy_wait_completion(cio);
> > +}
>
> Suppose the first call to "token = alloc_page()" fails (and
> cio->refcount == 0), isn't "cio" going to be leaked here?
>
> Maurizio

Agreed, will free it in "err_token", and will update next version.

Thank you,
Nitesh Shetty