From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Lukas Herbolt <lukas@herbolt.com>
Cc: <James.Bottomley@HansenPartnership.com>,
<martin.petersen@oracle.com>, <linux-scsi@vger.kernel.org>
Subject: Re: [PATCH 1/1] scsi: sd: Rounddown host->opt_sectors to logical
Date: Wed, 19 Nov 2025 22:26:50 -0500 [thread overview]
Message-ID: <yq1ecpt9yqb.fsf@ca-mkp.ca.oracle.com> (raw)
In-Reply-To: <20251114102853.1476938-4-lukas@herbolt.com> (Lukas Herbolt's message of "Fri, 14 Nov 2025 11:28:55 +0100")
Lukas,
> The host->opt_sectors are by default 512 bytes aligned if we have 4KN
> SAS disk reporting zero or smaller opt_xfer_block than the
> host->opt_sectors we will end up with unaligned queue_limit->io_opt.
I am intrigued wrt. which controller returns a host->opt_sectors that
would trigger this misalignment. What is the actual value reported?
> + lim.io_opt = rounddown(lim.logical_block_size,
> + sdp->host->opt_sectors << SECTOR_SHIFT);
Those parameters would need to be reversed, I think. You want to round
down opt_sectors and not the logical_block_size.
--
Martin K. Petersen
next prev parent reply other threads:[~2025-11-20 3:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-14 10:28 [PATCH 0/1] Fix unaligned queue_limit->io_opt on SAS and 4KN disk Lukas Herbolt
2025-11-14 10:28 ` [PATCH 1/1] scsi: sd: Rounddown host->opt_sectors to logical Lukas Herbolt
2025-11-20 3:26 ` Martin K. Petersen [this message]
2025-11-20 12:07 ` lukas
2025-11-20 16:07 ` John Garry
2025-11-21 8:34 ` lukas
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