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Subject: Re: [PATCH 01/10] block: introduce blk_is_valid_logical_block_size
From:   Maxim Levitsky <mlevitsk@redhat.com>
To:     Damien Le Moal <Damien.LeMoal@wdc.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc:     Keith Busch <kbusch@kernel.org>,
        Josef Bacik <josef@toxicpanda.com>,
        "open list:BLOCK LAYER" <linux-block@vger.kernel.org>,
        Sagi Grimberg <sagi@grimberg.me>, Jens Axboe <axboe@kernel.dk>,
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        "open list:SCSI CDROM DRIVER" <linux-scsi@vger.kernel.org>,
        Tejun Heo <tj@kernel.org>,
        Bart Van Assche <bvanassche@acm.org>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Jason Wang <jasowang@redhat.com>,
        Maxim Levitsky <maximlevitsky@gmail.com>,
        Stefan Hajnoczi <stefanha@redhat.com>,
        Colin Ian King <colin.king@canonical.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
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        Christoph Hellwig <hch@lst.de>,
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        Hou Tao <houtao1@huawei.com>, Jens Axboe <axboe@fb.com>,
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        <virtualization@lists.linux-foundation.org>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        Alex Dubov <oakad@yahoo.com>
Date:   Tue, 21 Jul 2020 14:09:16 +0300
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References: <20200721105239.8270-1-mlevitsk@redhat.com>
         <20200721105239.8270-2-mlevitsk@redhat.com>
         <CY4PR04MB37512BDEFD7B977FCD32A10AE7780@CY4PR04MB3751.namprd04.prod.outlook.com>
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On Tue, 2020-07-21 at 11:05 +0000, Damien Le Moal wrote:
> On 2020/07/21 19:53, Maxim Levitsky wrote:
> > Kernel block layer has never supported logical block
> > sizes less that SECTOR_SIZE nor larger that PAGE_SIZE.
> > 
> > Some drivers have runtime configurable block size,
> > so it makes sense to have common helper for that.
> 
> ...common helper to check the validity of the logical block size set by the driver.
Agree, will fix.
> 
> ("for that" does not refer to a clear action)
> 
> > Signed-off-by: Maxim Levitsky  <mlevitsk@redhat.com>
> > ---
> >  block/blk-settings.c   | 18 ++++++++++++++++++
> >  include/linux/blkdev.h |  1 +
> >  2 files changed, 19 insertions(+)
> > 
> > diff --git a/block/blk-settings.c b/block/blk-settings.c
> > index 9a2c23cd97007..3c4ef0d00c2bc 100644
> > --- a/block/blk-settings.c
> > +++ b/block/blk-settings.c
> > @@ -311,6 +311,21 @@ void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
> >  }
> >  EXPORT_SYMBOL(blk_queue_max_segment_size);
> >  
> > +
> > +/**
> > + * blk_check_logical_block_size - check if logical block size is supported
> > + * by the kernel
> > + * @size:  the logical block size, in bytes
> > + *
> > + * Description:
> > + *   This function checks if the block layers supports given block size
> > + **/
> > +bool blk_is_valid_logical_block_size(unsigned int size)
> > +{
> > +	return size >= SECTOR_SIZE && size <= PAGE_SIZE && !is_power_of_2(size);
Note here a typo, made in last minute change which I didn't test.
It should be without '!'

Best regards,
	Maxim Levitsky

> > +}
> > +EXPORT_SYMBOL(blk_is_valid_logical_block_size);
> > +
> >  /**
> >   * blk_queue_logical_block_size - set logical block size for the queue
> >   * @q:  the request queue for the device
> > @@ -323,6 +338,8 @@ EXPORT_SYMBOL(blk_queue_max_segment_size);
> >   **/
> >  void blk_queue_logical_block_size(struct request_queue *q, unsigned int size)
> >  {
> > +	WARN_ON(!blk_is_valid_logical_block_size(size));
> > +
> >  	q->limits.logical_block_size = size;
> >  
> >  	if (q->limits.physical_block_size < size)
> > @@ -330,6 +347,7 @@ void blk_queue_logical_block_size(struct request_queue *q, unsigned int size)
> >  
> >  	if (q->limits.io_min < q->limits.physical_block_size)
> >  		q->limits.io_min = q->limits.physical_block_size;
> > +
> 
> white line change.
> 
> >  }
> >  EXPORT_SYMBOL(blk_queue_logical_block_size);
> >  
> > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> > index 57241417ff2f8..2ed3151397e41 100644
> > --- a/include/linux/blkdev.h
> > +++ b/include/linux/blkdev.h
> > @@ -1099,6 +1099,7 @@ extern void blk_queue_max_write_same_sectors(struct request_queue *q,
> >  		unsigned int max_write_same_sectors);
> >  extern void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
> >  		unsigned int max_write_same_sectors);
> > +extern bool blk_is_valid_logical_block_size(unsigned int size);
> >  extern void blk_queue_logical_block_size(struct request_queue *, unsigned int);
> >  extern void blk_queue_max_zone_append_sectors(struct request_queue *q,
> >  		unsigned int max_zone_append_sectors);
> > 
> 
>