linux-kernel - Re: [PATCH] scsi/NCR5380: Remove in

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Message-ID: <X8pfD5XtLoOygdez@lx-t490>
Date:   Fri, 4 Dec 2020 17:08:47 +0100
From:   "Ahmed S. Darwish" <a.darwish@...utronix.de>
To:     Finn Thain <fthain@...egraphics.com.au>
Cc:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Michael Schmitz <schmitzmic@...il.com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] scsi/NCR5380: Remove in_interrupt() test

On Fri, Dec 04, 2020 at 10:08:08AM +1100, Finn Thain wrote:
...
>
> You've put your finger on a known problem with certain
> NCR5380_poll_politely() call sites. That is, the nominal timeout, HZ / 64,
> is meaningless because it is ignored in atomic context. So you may as well
> specify 0 jiffies at these call sites. (There will be a 1 jiffy timeout
> applied regardless.)
...
>
> However, I can see the value in your approach, i.e. passing a zero timeout
> to NCR5380_poll_politely() whenever that argument is unused. And I agree
> that this could then be used to inhibit sleeping, rather than testing
> irqs_disabled().
>
> So if you really don't like irqs_disabled(), perhaps you can just keep the
> better parts of your two attempts, i.e. passing 0 to
> NCR5380_poll_politely() where appropriate and facilitating that by adding
> a new can_sleep parameter to do_abort() and NCR5380_transfer_pio(), as in,
...
>
> Does that sound like a reasonable compromise?
>

Yes, of course. Thanks a lot.

I've sent a v2.

--
Ahmed S. Darwish
Linutronix GmbH