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From: Alexander Popov <alex.popov@linux.com>
To: Timur Tabi <timur@tabi.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Anatolij Gustschin <agust@denx.de>, Rob Herring <robh@kernel.org>,
	Grant Likely <grant.likely@linaro.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Vinod Koul <vinod.koul@intel.com>,
	Pawel Moll <pawel.moll@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Kumar Gala <galak@codeaurora.org>,
	linuxppc-dev@lists.ozlabs.org, dmaengine@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	Alexander Popov <alex.popov@linux.com>
Subject: Re: [PATCH v3 1/3] powerpc/512x: add LocalPlus Bus FIFO device driver
Date: Tue, 29 Sep 2015 09:34:07 +0300	[thread overview]
Message-ID: <560A30DF.9050900@linux.com> (raw)
In-Reply-To: <56093E1D.4080008@tabi.org>

On 28.09.2015 16:18, Timur Tabi wrote:
> Alexander Popov wrote:
>> The only question I have: why calling dma_unmap_single() from within
>> a spinlock is a bad practice?
> 
> I don't know, but usually functions that allocate or free memory cannot be
> called from within a spinlock.  You need to check that.  Since the MPC5121
> is a single-core CPU, you might not notice if you're doing something wrong.

I've double-checked the code and LDD and don't see any reason to avoid
calling dma_unmap_single() from interrupt context and within spinlock.

Please correct me if I'm wrong.
Thanks.

Best regards,
Alexander

WARNING: multiple messages have this Message-ID (diff)
From: Alexander Popov <alex.popov-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org>
To: Timur Tabi <timur-N01EOCouUvQ@public.gmane.org>,
	Benjamin Herrenschmidt
	<benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>,
	Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
	Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>,
	Anatolij Gustschin <agust-ynQEQJNshbs@public.gmane.org>,
	Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Grant Likely
	<grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Dan Williams
	<dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Vinod Koul <vinod.koul-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>,
	Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	Ian Campbell
	<ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>,
	Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
	linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
	dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Alexander Popov
	<alex.popov-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH v3 1/3] powerpc/512x: add LocalPlus Bus FIFO device driver
Date: Tue, 29 Sep 2015 09:34:07 +0300	[thread overview]
Message-ID: <560A30DF.9050900@linux.com> (raw)
In-Reply-To: <56093E1D.4080008-N01EOCouUvQ@public.gmane.org>

On 28.09.2015 16:18, Timur Tabi wrote:
> Alexander Popov wrote:
>> The only question I have: why calling dma_unmap_single() from within
>> a spinlock is a bad practice?
> 
> I don't know, but usually functions that allocate or free memory cannot be
> called from within a spinlock.  You need to check that.  Since the MPC5121
> is a single-core CPU, you might not notice if you're doing something wrong.

I've double-checked the code and LDD and don't see any reason to avoid
calling dma_unmap_single() from interrupt context and within spinlock.

Please correct me if I'm wrong.
Thanks.

Best regards,
Alexander
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  reply	other threads:[~2015-09-29  6:30 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-09-24 17:28 [PATCH v3 0/3] powerpc/512x: add LocalPlus Bus FIFO device driver Alexander Popov
2015-09-24 17:28 ` Alexander Popov
2015-09-24 17:28 ` [PATCH v3 1/3] " Alexander Popov
2015-09-25  1:01   ` Timur Tabi
2015-09-25  1:01     ` Timur Tabi
2015-09-28 13:13     ` Alexander Popov
2015-09-28 13:13       ` Alexander Popov
2015-09-28 13:18       ` Timur Tabi
2015-09-28 13:18         ` Timur Tabi
2015-09-29  6:34         ` Alexander Popov [this message]
2015-09-29  6:34           ` Alexander Popov
2015-09-30 21:24     ` Alexander Popov
2015-10-01 17:11       ` Timur Tabi
2015-10-01 17:11         ` Timur Tabi
2015-10-05 22:22         ` Alexander Popov
2015-09-24 17:28 ` [PATCH v3 2/3] powerpc/512x: add a device tree binding for LocalPlus Bus FIFO Alexander Popov
2015-09-25  0:18   ` Timur Tabi
2015-09-28 13:24     ` Alexander Popov
2015-09-28 13:26       ` Timur Tabi
2015-09-28 13:26         ` Timur Tabi
2015-09-29  6:35         ` Alexander Popov
2015-09-29  6:35           ` Alexander Popov
2015-09-24 17:28 ` [PATCH v3 3/3] dmaengine: mpc512x: initialize with subsys_initcall() Alexander Popov
2015-09-25  0:16   ` Timur Tabi
2015-09-28 13:15     ` Alexander Popov
2015-10-07 14:17   ` Vinod Koul
2015-10-07 14:17     ` Vinod Koul
2015-10-07 21:31     ` Alexander Popov

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