| Message ID | 20250218222209.1382449-5-alex.williamson@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | vfio: Improve DMA mapping performance for huge pfnmaps | expand |
On Tue, Feb 18, 2025 at 03:22:04PM -0700, Alex Williamson wrote: > Page count should more consistently be an unsigned long when passed as > an argument while functions returning a number of pages should use a > signed long to allow for -errno. > > vaddr_get_pfns() can therefore be upgraded to return long, though in > practice it's currently limited by the batch capacity. In fact, the > batch indexes are noted to never hold negative values, so while it > doesn't make sense to bloat the structure with unsigned longs in this > case, it does make sense to specify these as unsigned. > > No change in behavior expected. > > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com>
No change in behavior observed from v1 on my config (DGX H100). Thanks! Reviewed-by: "Mitchell Augustin" <mitchell.augustin@canonical.com> Tested-by: "Mitchell Augustin" <mitchell.augustin@canonical.com> On Tue, Feb 18, 2025 at 4:46 PM Peter Xu <peterx@redhat.com> wrote: > > On Tue, Feb 18, 2025 at 03:22:04PM -0700, Alex Williamson wrote: > > Page count should more consistently be an unsigned long when passed as > > an argument while functions returning a number of pages should use a > > signed long to allow for -errno. > > > > vaddr_get_pfns() can therefore be upgraded to return long, though in > > practice it's currently limited by the batch capacity. In fact, the > > batch indexes are noted to never hold negative values, so while it > > doesn't make sense to bloat the structure with unsigned longs in this > > case, it does make sense to specify these as unsigned. > > > > No change in behavior expected. > > > > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> > > Reviewed-by: Peter Xu <peterx@redhat.com> > > -- > Peter Xu >
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index fafd8af125c7..ce661f03f139 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -103,9 +103,9 @@ struct vfio_dma { struct vfio_batch { struct page **pages; /* for pin_user_pages_remote */ struct page *fallback_page; /* if pages alloc fails */ - int capacity; /* length of pages array */ - int size; /* of batch currently */ - int offset; /* of next entry in pages */ + unsigned int capacity; /* length of pages array */ + unsigned int size; /* of batch currently */ + unsigned int offset; /* of next entry in pages */ }; struct vfio_iommu_group { @@ -560,14 +560,14 @@ static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm, * initial offset. For VM_PFNMAP pfns, only the returned number of pfns and * returned initial pfn are provided; subsequent pfns are contiguous. */ -static int vaddr_get_pfns(struct mm_struct *mm, unsigned long vaddr, - long npages, int prot, unsigned long *pfn, - struct vfio_batch *batch) +static long vaddr_get_pfns(struct mm_struct *mm, unsigned long vaddr, + unsigned long npages, int prot, unsigned long *pfn, + struct vfio_batch *batch) { - long pin_pages = min_t(long, npages, batch->capacity); + unsigned long pin_pages = min_t(unsigned long, npages, batch->capacity); struct vm_area_struct *vma; unsigned int flags = 0; - int ret; + long ret; if (prot & IOMMU_WRITE) flags |= FOLL_WRITE; @@ -612,7 +612,7 @@ static int vaddr_get_pfns(struct mm_struct *mm, unsigned long vaddr, * first page and all consecutive pages with the same locking. */ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr, - long npage, unsigned long *pfn_base, + unsigned long npage, unsigned long *pfn_base, unsigned long limit, struct vfio_batch *batch) { unsigned long pfn; @@ -724,7 +724,7 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr, } static long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova, - unsigned long pfn, long npage, + unsigned long pfn, unsigned long npage, bool do_accounting) { long unlocked = 0, locked = 0;
Page count should more consistently be an unsigned long when passed as an argument while functions returning a number of pages should use a signed long to allow for -errno. vaddr_get_pfns() can therefore be upgraded to return long, though in practice it's currently limited by the batch capacity. In fact, the batch indexes are noted to never hold negative values, so while it doesn't make sense to bloat the structure with unsigned longs in this case, it does make sense to specify these as unsigned. No change in behavior expected. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> --- drivers/vfio/vfio_iommu_type1.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)