From: Paolo Bonzini <pbonzini@redhat.com>
To: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: mchristi@redhat.com, linux-scsi@vger.kernel.org
Subject: Re: [PATCH 1/1] scsi: add Synology to 1024 sector blacklist
Date: Wed, 13 Jan 2016 11:27:12 +0100 [thread overview]
Message-ID: <56962680.6020303@redhat.com> (raw)
In-Reply-To: <1452678977.27508.82.camel@haakon3.risingtidesystems.com>
On 13/01/2016 10:56, Nicholas A. Bellinger wrote:
> Nope, or at least not in iblock_configure_device() code.
>
> The MAXIMUM TRANSFER LENGTH in block limits EVPD for IBLOCK is
> queue_max_hw_sectors() * bdev_logical_block_size, and
> queue_max_segments() is not considered atm.
>
> Is there a case where MTL needs to be the smaller of the two..?
Given enough fragmentation of the t_data_sg, the actual MTL will be
queue_max_segments() * PAGE_SIZE bytes.
I think it's a bug in LIO that target_alloc_sgl always does order-0
allocation. But until that is fixed, LIO will be susceptible to this
problem, at least for PSCSI backends (for BLOCK and FILEIO, the block
and VFS layers can always split one I/O down to multiple requests).
Paolo
next prev parent reply other threads:[~2016-01-13 10:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-07 22:34 [PATCH 1/1] scsi: add Synology to 1024 sector blacklist mchristi
2016-01-08 2:44 ` Martin K. Petersen
2016-01-12 17:54 ` Paolo Bonzini
2016-01-13 9:33 ` Nicholas A. Bellinger
2016-01-13 9:41 ` Paolo Bonzini
2016-01-13 9:56 ` Nicholas A. Bellinger
2016-01-13 10:27 ` Paolo Bonzini [this message]
-- strict thread matches above, loose matches on Subject: below --
2015-05-22 19:22 michaelc
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