From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH] Changing the AMD IOMMU API path to work in an atomic context which is necessary for any custom drivers using the IOMMU API while holding a spinlock. Date: Sun, 26 Aug 2018 23:58:41 -0700 Message-ID: <20180827065841.GA7053@infradead.org> References: <1535120929-5693-1-git-send-email-murphyt7@tcd.ie> <20180824145328.GA7996@infradead.org> <24d3f04a-e6e2-ed8f-e2bd-b38144f33f26@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <24d3f04a-e6e2-ed8f-e2bd-b38144f33f26-5wv7dgnIgG8@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Robin Murphy Cc: iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, murphyt7-/Zw1syy4LHg@public.gmane.org List-Id: iommu@lists.linux-foundation.org On Fri, Aug 24, 2018 at 04:24:49PM +0100, Robin Murphy wrote: > Although IIRC the AMD driver is in fact the only one whose map/unmap > callbacks aren't already spinlock-safe (or at least it was last time I was > looking). Stuff like iommu-dma is already relying on this in order to > implement streaming DMA API calls (which may be in atomic context) on top of > the corresponding IOMMU API operations. True. That should be mentioned in the spinlock, though - and once it is done the calling conventions should be documented.