From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: John Garry <john.garry@huawei.com>
Cc: Bart Van Assche <bvanassche@acm.org>, <jejb@linux.ibm.com>,
<martin.petersen@oracle.com>, <linux-scsi@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <ming.lei@redhat.com>
Subject: Re: [PATCH] scsi: core: Cap shost cmd_per_lun at can_queue
Date: Sat, 22 May 2021 00:28:22 -0400 [thread overview]
Message-ID: <yq1bl93z9su.fsf@ca-mkp.ca.oracle.com> (raw)
In-Reply-To: <a838c8e2-6513-a266-f145-5bcaed0a4f96@huawei.com> (John Garry's message of "Thu, 20 May 2021 17:41:15 +0100")
John,
> I don't mind doing that, but is there any requirement for can_queue to
> not be limited to 16b?
>
> It seems intentional that can_queue is int and cmd_per_lun is short.
I suspect cmd_per_lun was originally chosen to be 16 bits because of FC
(SPI was 8 bits). And that it seemed unreasonable that the initiator
should be limited to what a single LUN could express. But this is all
guesswork. This code was obviously written a very, very long time ago...
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2021-05-22 4:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-19 14:31 [PATCH] scsi: core: Cap shost cmd_per_lun at can_queue John Garry
2021-05-20 1:24 ` Ming Lei
2021-05-20 15:57 ` Bart Van Assche
2021-05-20 16:41 ` John Garry
2021-05-20 16:57 ` Bart Van Assche
2021-05-20 17:24 ` John Garry
2021-05-22 4:28 ` Martin K. Petersen [this message]
2021-05-22 4:35 ` Martin K. Petersen
2021-05-26 4:07 ` Martin K. Petersen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=yq1bl93z9su.fsf@ca-mkp.ca.oracle.com \
--to=martin.petersen@oracle.com \
--cc=bvanassche@acm.org \
--cc=jejb@linux.ibm.com \
--cc=john.garry@huawei.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=ming.lei@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).