Date: Thu, 18 Dec 2014 14:50:09 -0600
From: atull <atull@opensource.altera.com>
To: Grant Likely <grant.likely@linaro.org>
CC: Pavel Machek <pavel@denx.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
        "H. Peter Anvin" <hpa@zytor.com>, "Michal Simek" <monstr@monstr.eu>,
        Michal Simek <michal.simek@xilinx.com>,
        "Randy Dunlap" <rdunlap@infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        Pantelis Antoniou <pantelis.antoniou@konsulko.com>,
        Rob Herring <robh+dt@kernel.org>, "Ira Snyder" <iws@ovro.caltech.edu>,
        "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
        Mark Brown <broonie@kernel.org>, <philip@balister.org>,
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        Steffen Trumtrar <s.trumtrar@pengutronix.de>,
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        Mauro Carvalho Chehab <m.chehab@samsung.com>,
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        Andrew Morton <akpm@linux-foundation.org>,
        "Linus Walleij" <linus.walleij@linaro.org>,
        Alan Tull <delicious.quinoa@gmail.com>,
        <dinguyen@opensource.altera.com>,
        Yves Vandervennet <yvanderv@opensource.altera.com>
Subject: Re: [PATCH v2 2/3] fpga manager: framework core
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References: <1414007405-32186-1-git-send-email-atull@opensource.altera.com> <1414007405-32186-3-git-send-email-atull@opensource.altera.com> <20141024105200.GA20775@amd> <CACxGe6sa=ysJAjx5TQZH5sKoas1PkoUUR4zT=Z35+uF6rrk-vw@mail.gmail.com>
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On Sat, 6 Dec 2014, Grant Likely wrote:

> >> +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?
> 
> Custom locking schemes are just wrong. A mutex is the right thing to
> do here and then an -EBUSY isn't required.
> 

I've changed it to a mutex in the next version.

> >
> >> +static ssize_t fpga_mgr_firmware_store(struct device *dev,
> >> +                                    struct device_attribute *attr,
> >> +                                    const char *buf, size_t count)
> >> +{
> >> +     struct fpga_manager *mgr = dev_get_drvdata(dev);
> >> +     unsigned int len;
> >> +     char image_name[NAME_MAX];
> 
> Hard coding a string length is a warning sign. That is the sort of
> thing that can memdup() or strdup() can handle.
> 

OK, I'll fix it using kstrdup() in v6.

Alan
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