Messages in this thread | | | 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. | From | Robin Murphy <> | Date | Fri, 24 Aug 2018 16:24:49 +0100 |
| |
On 24/08/18 15:53, Christoph Hellwig wrote: > On Fri, Aug 24, 2018 at 02:28:49PM +0000, murphyt7@tcd.ie wrote: >> From: Tom Murphy <murphyt7@tcd.ie> >> >> --- >> >> This patch allows the IOMMU API path in the AMD driver to be called from an atomic context. >> This is useful for anyone building a driver which needs to call the IOMMU API while holding a spinlock. > > I don't think that is a good idea. Please point to the code in the > driver and we can't probably find a better solution.
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.
Robin.
| |