Re: [RFC v2 09/11] block/bdev: lift block size restrictions and use common definition

Ming Lei
2024-12-16T09:20:06Z

On Mon, Dec 16, 2024 at 4:58 PM John Garry <john.g.garry@oracle.com> wrote:
>
> On 14/12/2024 03:10, Luis Chamberlain wrote:
> > index 167d82b46781..b57dc4bff81b 100644
> > --- a/block/bdev.c
> > +++ b/block/bdev.c
> > @@ -157,8 +157,7 @@ int set_blocksize(struct file *file, int size)
> > struct inode *inode = file->f_mapping->host;
> > struct block_device *bdev = I_BDEV(inode);
> >
> > - /* Size must be a power of two, and between 512 and PAGE_SIZE */
> > - if (size > PAGE_SIZE || size < 512 || !is_power_of_2(size))
> > + if (blk_validate_block_size(size))
> > return -EINVAL;
>
> I suppose that this can be sent as a separate patch to be merged now.

There have been some bugs found in case that PAGE_SIZE == 64K, and I
think it is bad to use PAGE_SIZE for validating many hw/queue limits, we might
have to fix them first.

Such as:

1) blk_validate_limits()

- failure if max_segment_size is less than 64K

- max_user_sectors

if (lim->max_user_sectors < PAGE_SIZE / SECTOR_SIZE)
return -EINVAL;

2) bio_may_need_split()

- max_segment_size may be less than 64K

Thanks,