| Message ID | 20200512090058.14910-3-m.szyprowski@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | DRM: fix struct sg_table nents vs. orig_nents misuse | expand |
On Tue, May 12, 2020 at 11:00:23AM +0200, Marek Szyprowski wrote: > struct sg_table is a common structure used for describing a memory > buffer. It consists of a scatterlist with memory pages and DMA addresses > (sgl entry), as well as the number of scatterlist entries: CPU pages > (orig_nents entry) and DMA mapped pages (nents entry). > > It turned out that it was a common mistake to misuse nents and orig_nents > entries, calling mapping functions with a wrong number of entries. > > To avoid such issues, lets introduce a common wrapper operating directly > on the struct sg_table objects, which take care of the proper use of > the nents and orig_nents entries. > > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Looks good, Reviewed-by: Christoph Hellwig <hch@lst.de>
Hi Marek, On Tue, May 12, 2020 at 11:00:23AM +0200, Marek Szyprowski wrote: > --- > include/linux/iommu.h | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) Some nits below, with those fixed: Acked-by: Joerg Roedel <jroedel@suse.de> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 7cfd2dd..ba662ba 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -478,6 +478,22 @@ extern size_t iommu_map_sg_atomic(struct iommu_domain *domain, > extern void iommu_set_fault_handler(struct iommu_domain *domain, > iommu_fault_handler_t handler, void *token); > > +/** > + * iommu_map_sgtable - Map the given buffer to the IOMMU domain > + * @domain: The IOMMU domain to perfor ^^^^^^ Truncated comment? > + * @iova: The start addrees to map the buffer ^^^^^^^ Typo > + * @sgt: The sg_table object describing the buffer > + * @prot: IOMMU protection bits > + * > + * Create a mapping at @iova for the buffer described by a scatterlist > + * stored in the given sg_table object in the provided IOMMU domain. > + */ > +static inline size_t iommu_map_sgtable(struct iommu_domain *domain, > + unsigned long iova, struct sg_table *sgt, int prot) > +{ > + return iommu_map_sg(domain, iova, sgt->sgl, sgt->orig_nents, prot); > +} > + > extern void iommu_get_resv_regions(struct device *dev, struct list_head *list); > extern void iommu_put_resv_regions(struct device *dev, struct list_head *list); > extern void generic_iommu_put_resv_regions(struct device *dev, > -- > 1.9.1
On 2020-05-12 10:00 am, Marek Szyprowski wrote: > struct sg_table is a common structure used for describing a memory > buffer. It consists of a scatterlist with memory pages and DMA addresses > (sgl entry), as well as the number of scatterlist entries: CPU pages > (orig_nents entry) and DMA mapped pages (nents entry). > > It turned out that it was a common mistake to misuse nents and orig_nents > entries, calling mapping functions with a wrong number of entries. > > To avoid such issues, lets introduce a common wrapper operating directly > on the struct sg_table objects, which take care of the proper use of > the nents and orig_nents entries. Modulo Joerg's comments, Reviewed-by: Robin Murphy <robin.murphy@arm.com> > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> > --- > For more information, see '[PATCH v4 00/38] DRM: fix struct sg_table nents > vs. orig_nents misuse' thread: > https://lore.kernel.org/dri-devel/20200512085710.14688-1-m.szyprowski@samsung.com/T/ > --- > include/linux/iommu.h | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 7cfd2dd..ba662ba 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -478,6 +478,22 @@ extern size_t iommu_map_sg_atomic(struct iommu_domain *domain, > extern void iommu_set_fault_handler(struct iommu_domain *domain, > iommu_fault_handler_t handler, void *token); > > +/** > + * iommu_map_sgtable - Map the given buffer to the IOMMU domain > + * @domain: The IOMMU domain to perfor > + * @iova: The start addrees to map the buffer > + * @sgt: The sg_table object describing the buffer > + * @prot: IOMMU protection bits > + * > + * Create a mapping at @iova for the buffer described by a scatterlist > + * stored in the given sg_table object in the provided IOMMU domain. > + */ > +static inline size_t iommu_map_sgtable(struct iommu_domain *domain, > + unsigned long iova, struct sg_table *sgt, int prot) > +{ > + return iommu_map_sg(domain, iova, sgt->sgl, sgt->orig_nents, prot); > +} > + > extern void iommu_get_resv_regions(struct device *dev, struct list_head *list); > extern void iommu_put_resv_regions(struct device *dev, struct list_head *list); > extern void generic_iommu_put_resv_regions(struct device *dev, >
diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 7cfd2dd..ba662ba 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -478,6 +478,22 @@ extern size_t iommu_map_sg_atomic(struct iommu_domain *domain, extern void iommu_set_fault_handler(struct iommu_domain *domain, iommu_fault_handler_t handler, void *token); +/** + * iommu_map_sgtable - Map the given buffer to the IOMMU domain + * @domain: The IOMMU domain to perfor + * @iova: The start addrees to map the buffer + * @sgt: The sg_table object describing the buffer + * @prot: IOMMU protection bits + * + * Create a mapping at @iova for the buffer described by a scatterlist + * stored in the given sg_table object in the provided IOMMU domain. + */ +static inline size_t iommu_map_sgtable(struct iommu_domain *domain, + unsigned long iova, struct sg_table *sgt, int prot) +{ + return iommu_map_sg(domain, iova, sgt->sgl, sgt->orig_nents, prot); +} + extern void iommu_get_resv_regions(struct device *dev, struct list_head *list); extern void iommu_put_resv_regions(struct device *dev, struct list_head *list); extern void generic_iommu_put_resv_regions(struct device *dev,
struct sg_table is a common structure used for describing a memory buffer. It consists of a scatterlist with memory pages and DMA addresses (sgl entry), as well as the number of scatterlist entries: CPU pages (orig_nents entry) and DMA mapped pages (nents entry). It turned out that it was a common mistake to misuse nents and orig_nents entries, calling mapping functions with a wrong number of entries. To avoid such issues, lets introduce a common wrapper operating directly on the struct sg_table objects, which take care of the proper use of the nents and orig_nents entries. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- For more information, see '[PATCH v4 00/38] DRM: fix struct sg_table nents vs. orig_nents misuse' thread: https://lore.kernel.org/dri-devel/20200512085710.14688-1-m.szyprowski@samsung.com/T/ --- include/linux/iommu.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)