From: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
To: Pavel Machek <pavel@denx.de>
Cc: atull@opensource.altera.com, gregkh@linuxfoundation.org,
jgunthorpe@obsidianresearch.com, hpa@zytor.com, monstr@monstr.eu,
michal.simek@xilinx.com, rdunlap@infradead.org,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
pantelis.antoniou@konsulko.com, robh+dt@kernel.org,
grant.likely@linaro.org, iws@ovro.caltech.edu,
linux-doc@vger.kernel.org, broonie@kernel.org,
philip@balister.org, rubini@gnudd.com, s.trumtrar@pengutronix.de,
jason@lakedaemon.net, kyle.teske@ni.com, nico@linaro.org,
balbi@ti.com, m.chehab@samsung.com, davidb@codeaurora.org,
rob@landley.net, davem@davemloft.net, cesarb@cesarb.net,
sameo@linux.intel.com, akpm@linux-foundation.org,
linus.walleij@linaro.org, delicious.quinoa@gmail.com,
dinguyen@opensource.altera.com, yvanderv@opensource.altera.com
Subject: Re: [PATCH v2 2/3] fpga manager: framework core
Date: Fri, 24 Oct 2014 22:00:13 +0100 [thread overview]
Message-ID: <20141024220013.37c38f7a@alan.etchedpixels.co.uk> (raw)
In-Reply-To: <20141024105200.GA20775@amd>
> > +int fpga_mgr_write(struct fpga_manager *mgr, const char *buf, size_t count)
> > +{
> > + int ret;
> > +
> > + if (test_and_set_bit_lock(FPGA_MGR_BUSY, &mgr->flags))
> > + return -EBUSY;
> > +
> > + dev_info(mgr->dev, "writing buffer to %s\n", mgr->name);
> > +
> > + ret = __fpga_mgr_write(mgr, buf, count);
> > + clear_bit_unlock(FPGA_MGR_BUSY, &mgr->flags);
> > +
> > + return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(fpga_mgr_write);
>
> Is the EBUSY -- userspace please try again, but you don't know when to
> try again -- right interface? I mean, normally kernel would wait, so
> that userland does not have to poll?
And if userland has to also support polling you must support poll/select
on the file handle so it knows when to retry the I/O.
The error should be EAGAIN for a retriable write with O_NDELAY set.
Alan
next prev parent reply other threads:[~2014-10-24 21:00 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-22 19:50 [PATCH v2 0/3] FPGA Framework with DT and sysfs support atull-yzvPICuk2ABMcg4IHK0kFoH6Mc4MB0Vx
2014-10-22 19:50 ` [PATCH v2 1/3] fpga manager: add sysfs interface document atull
2014-10-22 19:50 ` [PATCH v2 2/3] fpga manager: framework core atull
2014-10-24 10:52 ` Pavel Machek
2014-10-24 10:55 ` Pantelis Antoniou
2014-10-24 14:54 ` atull
2014-12-06 13:01 ` Grant Likely
2014-12-06 13:55 ` Pavel Machek
2014-12-08 17:50 ` Grant Likely
2014-12-08 17:56 ` Grant Likely
2014-12-08 17:56 ` Pantelis Antoniou
2014-12-08 18:30 ` Grant Likely
2014-12-08 20:53 ` Rob Landley
2014-10-24 21:00 ` One Thousand Gnomes [this message]
2014-12-06 13:00 ` Grant Likely
2014-12-06 14:02 ` Pavel Machek
[not found] ` <CACxGe6sa=ysJAjx5TQZH5sKoas1PkoUUR4zT=Z35+uF6rrk-vw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-12-08 22:55 ` One Thousand Gnomes
2014-12-09 13:11 ` Grant Likely
2014-12-09 13:42 ` Michal Simek
2014-12-09 16:07 ` atull
2014-12-09 21:02 ` One Thousand Gnomes
2014-12-09 22:12 ` atull
2014-12-12 12:14 ` Pavel Machek
2014-12-18 20:50 ` atull
2014-10-22 19:50 ` [PATCH v2 3/3] fpga manager: bus driver atull
2014-10-22 22:22 ` atull
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