From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Popov Subject: Re: [PATCH v3 1/3] powerpc/512x: add LocalPlus Bus FIFO device driver Date: Tue, 29 Sep 2015 09:34:07 +0300 Message-ID: <560A30DF.9050900@linux.com> References: <1443115737-3948-1-git-send-email-alex.popov@linux.com> <1443115737-3948-2-git-send-email-alex.popov@linux.com> <56049CD0.7080104@tabi.org> <56093CE5.5070301@linux.com> <56093E1D.4080008@tabi.org> Reply-To: alex.popov-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <56093E1D.4080008-N01EOCouUvQ@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Timur Tabi , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Anatolij Gustschin , Rob Herring , Grant Likely , Dan Williams , Vinod Koul , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , 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 List-Id: devicetree@vger.kernel.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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html