From: Christoph Hellwig <hch@lst.de>
To: Tom Yan <tom.ty89@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>,
linux-scsi@vger.kernel.org, dgilbert@interlog.com,
Bart Van Assche <bvanassche@acm.org>,
Alan Stern <stern@rowland.harvard.edu>,
akinobu.mita@gmail.com, linux-api@vger.kernel.org
Subject: Re: [PATCH RESEND 2/4] scsi: sg: implement BLKSSZGET
Date: Tue, 8 Sep 2020 10:42:58 +0200 [thread overview]
Message-ID: <20200908084258.GA17030@lst.de> (raw)
In-Reply-To: <CAGnHSEnWPSaM3xS1MtFUJDrSZPfaH_VwAiQ5UkndFTVe3uWNVA@mail.gmail.com>
On Mon, Sep 07, 2020 at 05:01:34PM +0800, Tom Yan wrote:
> Feel free to omit this. But then you will probably want to ditch
> BLKSECTGET as well, and then any usage of queue_max_sectors(), and
> maybe more/all queue_*().
>
> I'm not really interested in discussing/arguing whether
> general/ideally-speaking it's appropriate/necessary to keep BLKSECTGET
> / add BLKSSZGET. The only reason I added this is that, when BLKSECTGET
> was introduced to sg long time ago, it was wrongly implemented to
> gives out the limit in bytes, so now when I'm fixing it, I'm merely
> making sure that whatever has been relying on the ioctl (e.g. qemu)
> will only need to do one more ioctl (instead of e.g. doing SCSI in its
> non-SCSI-specific part), if they want/need the limit in bytes. If they
> can be implemented more "generic"-ly, feel free to improve/extend them
> to make them "SG_*-qualified".
>
> Even if you can do SCSI from the userspace, or even should, I don't
> see any reason that we shouldn't provide an ioctl to do
> queue_logical_block_size() *while we provide one to do
> queue_max_sectors()*.
Well, the different definition in bytes for sg actually makes sense
to me, as a bytes based limit is what fundamentally makes sense for
the passthrough interface. Only that it reuses the same cmd value
is a bit confusing. So instead of changing anything and potentially
breaking applications I'd suggest to just better document the semantics.
next prev parent reply other threads:[~2020-09-08 8:43 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 4:42 About BLKSECTGET in sg Tom Yan
2020-09-04 16:28 ` Douglas Gilbert
2020-09-04 19:21 ` Tom Yan
2020-09-04 20:05 ` [PATCH 1/4] scsi: sg: fix BLKSECTGET ioctl Tom Yan
2020-09-04 20:05 ` [PATCH 2/4] scsi: sg: implement BLKSSZGET Tom Yan
2020-09-05 18:37 ` Douglas Gilbert
2020-09-04 20:05 ` [PATCH 3/4] scsi: sg: use queue_logical_sector_size() in max_sectors_bytes() Tom Yan
2020-09-05 18:37 ` Douglas Gilbert
2020-09-04 20:05 ` [PATCH 4/4] block/scsi_ioctl.c: " Tom Yan
2020-09-05 18:37 ` Douglas Gilbert
2020-09-05 18:37 ` [PATCH 1/4] scsi: sg: fix BLKSECTGET ioctl Douglas Gilbert
2020-09-05 19:32 ` Bart Van Assche
2020-09-05 20:36 ` Douglas Gilbert
2020-09-06 1:19 ` Tom Yan
2020-09-06 1:25 ` [PATCH RESEND " Tom Yan
2020-09-06 1:25 ` [PATCH RESEND 2/4] scsi: sg: implement BLKSSZGET Tom Yan
2020-09-06 1:25 ` [PATCH RESEND 3/4] scsi: sg: use queue_logical_sector_size() in max_sectors_bytes() Tom Yan
2020-09-06 1:25 ` [PATCH RESEND 4/4] block/scsi_ioctl.c: " Tom Yan
2020-09-06 1:27 ` [PATCH RESEND 1/4] scsi: sg: fix BLKSECTGET ioctl Tom Yan
2020-09-06 1:27 ` [PATCH RESEND 2/4] scsi: sg: implement BLKSSZGET Tom Yan
2020-09-07 6:09 ` Christoph Hellwig
2020-09-07 9:01 ` Tom Yan
2020-09-08 8:42 ` Christoph Hellwig [this message]
2020-09-10 1:59 ` Tom Yan
2020-09-10 5:28 ` Christoph Hellwig
2020-09-11 2:52 ` Tom Yan
2020-09-11 6:48 ` Christoph Hellwig
2020-09-11 17:52 ` Douglas Gilbert
2020-09-11 21:33 ` Alan Stern
2020-09-16 5:47 ` Tom Yan
2020-09-06 1:27 ` [PATCH RESEND 3/4] scsi: sg: use queue_logical_sector_size() in max_sectors_bytes() Tom Yan
2020-09-06 6:26 ` Greg KH
2020-09-06 7:01 ` Tom Yan
2020-09-06 7:40 ` [PATCH v2 1/4] scsi: sg: fix BLKSECTGET ioctl Tom Yan
2020-09-06 7:40 ` [PATCH v2 2/4] scsi: sg: implement BLKSSZGET Tom Yan
2020-09-06 7:40 ` [PATCH v2 3/4] scsi: sg: use queue_logical_sector_size() in max_sectors_bytes() Tom Yan
2020-09-06 7:40 ` [PATCH v2 4/4] block/scsi_ioctl.c: " Tom Yan
2020-09-06 7:51 ` [PATCH v3 1/4] scsi: sg: fix BLKSECTGET ioctl Tom Yan
2020-09-06 7:51 ` [PATCH v3 2/4] scsi: sg: implement BLKSSZGET Tom Yan
2020-09-06 7:51 ` [PATCH v3 3/4] scsi: sg: use queue_logical_sector_size() in max_sectors_bytes() Tom Yan
2020-09-06 7:51 ` [PATCH v3 4/4] block/scsi_ioctl.c: " Tom Yan
2020-09-06 1:27 ` [PATCH RESEND " Tom Yan
2020-09-06 5:09 ` [PATCH 1/4] scsi: sg: fix BLKSECTGET ioctl Douglas Gilbert
2020-09-06 7:16 ` Tom Yan
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