From: Oliver Neukum <oneukum@suse.com>
To: Pavel Machek <pavel@denx.de>
Cc: gregkh@linuxfoundation.org, stern@rowland.harvard.edu,
johan@kernel.org, gustavoars@kernel.org,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] usb: yurex: Rearrange code not to need GFP_ATOMIC
Date: Mon, 21 Sep 2020 15:00:16 +0200 [thread overview]
Message-ID: <1600693216.2424.92.camel@suse.com> (raw)
In-Reply-To: <20200921125237.GA24776@duo.ucw.cz>
Am Montag, den 21.09.2020, 14:52 +0200 schrieb Pavel Machek:
> Hi!
> >
> > Task goes to TASK_INTERRUPTIBLE
> >
> > > if (retval >= 0)
> > > timeout = schedule_timeout(YUREX_WRITE_TIMEOUT);
> >
> > Task turns into Sleeping Beauty until timeout
>
> Is there way to do the allocations for submit_urb before the
No. In theory you do not even know which HC will get the URB.
Preallocating resources is impossible. I do consider this a
design bug in the usbcore API.
> prepare_to_wait? GFP_ATOMIC would be nice to avoid... and doing
> GFP_ATOMIC from normal process context just because of task_state
> seems ... wrong.
Well, then you will need to change the rest of the logic
and use a struct completion. Give the age and practical
relevance of the driver I would recommend against making
such drastic changes and let it just be in its awkward
but correct state.
Regards
Oliver
next prev parent reply other threads:[~2020-09-21 13:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-20 8:44 [PATCH] usb: yurex: Rearrange code not to need GFP_ATOMIC Pavel Machek
2020-09-21 12:24 ` Oliver Neukum
2020-09-21 12:52 ` Pavel Machek
2020-09-21 13:00 ` Oliver Neukum [this message]
2020-09-21 14:45 ` Alan Stern
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