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	id 2A79768B05; Mon, 23 Jun 2025 15:35:43 +0200 (CEST)
Date: Mon, 23 Jun 2025 15:35:43 +0200
From: Christoph Hellwig <hch@lst.de>
To: John Garry <john.g.garry@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Bart Van Assche <bvanassche@acm.org>,
	Ming Lei <ming.lei@redhat.com>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>, "Ewan D. Milne" <emilne@redhat.com>,
	Laurence Oberman <loberman@redhat.com>, linux-rdma@vger.kernel.org,
	linux-scsi@vger.kernel.org, linux-block@vger.kernel.org
Subject: Re: [PATCH 2/2] scsi: enforce unlimited max_segment_size when
 virt_boundary_mask is set
Message-ID: <20250623133542.GA27271@lst.de>
References: <20250623080326.48714-1-hch@lst.de> <20250623080326.48714-3-hch@lst.de> <447ba437-9742-4686-b159-bc2086c9b814@oracle.com>
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On Mon, Jun 23, 2025 at 09:37:10AM +0100, John Garry wrote:
>> -	else
>> -		shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
>> +	if (sht->virt_boundary_mask)
>> +		shost->virt_boundary_mask = sht->virt_boundary_mask;
>
> nit: you could just always set shost->virt_boundary_mask = 
> sht->virt_boundary_mask

I could, but it would change behavior and break drivers.  The SCSI
midlayer allows overriding the template provided values in the host
itself after allocating and before adding it.  For the
virt_boundary_mask that features is used by iser and srp.

>> +	if (shost->virt_boundary_mask) {
>
> Or combine into a single if-else statement.
>
>> +		WARN_ON_ONCE(sht->max_segment_size &&
>> +			     sht->max_segment_size != UINT_MAX);
>> +		shost->max_segment_size = UINT_MAX;
>> +	} else {
>
> else if might be nicer, by maybe not as (I think) {} should be used and 
> that is not pretty for single line statements.

I also really want to keep the virt boundary vs non virt boundary cases
visually separe as that's the main branch.