On Mon, Apr 05, 2021 at 12:11:03PM -0700, Isaac J. Manjarres wrote:
> Mapping memory into io-pgtables follows the same semantics
> that unmapping memory used to follow (i.e. a buffer will be
> mapped one page block per call to the io-pgtable code). This
> means that it can be optimized in the same way that unmapping
> memory was, so add a map_pages() callback to the io-pgtable
> ops structure, so that a range of pages of the same size
> can be mapped within the same call.
>
> Signed-off-by: Isaac J. Manjarres <isa...@codeaurora.org>
> Suggested-by: Will Deacon <w...@kernel.org>
> ---
> include/linux/io-pgtable.h | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
> index 2ed0c057d9e7..019149b204b8 100644
> --- a/include/linux/io-pgtable.h
> +++ b/include/linux/io-pgtable.h
> @@ -143,6 +143,7 @@ struct io_pgtable_cfg {
> * struct io_pgtable_ops - Page table manipulation API for IOMMU drivers.
> *
> * @map: Map a physically contiguous memory region.
> + * @map_pages: Map a physically contiguous range of pages of the same
> size.
> * @unmap: Unmap a physically contiguous memory region.
> * @unmap_pages: Unmap a range of virtually contiguous pages of the same
> size.
> * @iova_to_phys: Translate iova to physical address.
> @@ -153,6 +154,9 @@ struct io_pgtable_cfg {
> struct io_pgtable_ops {
> int (*map)(struct io_pgtable_ops *ops, unsigned long iova,
> phys_addr_t paddr, size_t size, int prot, gfp_t gfp);
> + int (*map_pages)(struct io_pgtable_ops *ops, unsigned long iova,
> + phys_addr_t paddr, size_t pgsize, size_t pgcount,
> + int prot, gfp_t gfp, size_t *mapped);
How about returning 'size_t' and using IS_ERR_VALUE() instead of adding
the extra 'mapped' argument (i.e. return the size of the region mapped
or an error code)? I don't think we realistically need to care about map
sizes that overlap with the error region.
Will
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