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Date: Tue, 17 Mar 2026 15:36:51 +0100
From: Christoph Hellwig <hch@lst.de>
To: John Garry <john.g.garry@oracle.com>
Cc: "Ionut Nechita (Wind River)" <ionut.nechita@windriver.com>,
	m.szyprowski@samsung.com, kbusch@kernel.org, axboe@kernel.dk,
	hch@lst.de, sagi@grimberg.me, robin.murphy@arm.com,
	martin.petersen@oracle.com, damien.lemoal@opensource.wdc.com,
	ahuang12@lenovo.com, iommu@lists.linux.dev,
	linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org, ionut_n2001@yahoo.com,
	sunlightlinux@gmail.com
Subject: Re: [PATCH v1 0/2] dma: fix dma_opt_mapping_size() returning bogus
 value when no backend hint exists
Message-ID: <20260317143651.GA5186@lst.de>
References: <20260316203956.64515-1-ionut.nechita@windriver.com> <8b7706a0-41be-44a2-8247-ebbc33fee937@oracle.com>
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On Tue, Mar 17, 2026 at 09:11:59AM +0000, John Garry wrote:
> For SAS controllers, don't we limit shost->opt_sectors at 
> shost->max_sectors, and then in sd_revalidate_disk() this value is ignored 
> as sdkp->opt_xfer_blocks would be smaller, right?

That assumes opt_xfer_blocks is actually set.  It's an optional and
relatively recent SCSI feature.  So don't expect crappy SSDs or
RAID controllers faking up SCSI in shitty firmware to actually set
it.