The patch titled
Subject: mm: add a vmap_pfn function
has been added to the -mm tree. Its filename is
mm-add-a-vmap_pfn-function.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-add-a-vmap_pfn-function.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-add-a-vmap_pfn-function.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: mm: add a vmap_pfn function
Add a proper helper to remap PFNs into kernel virtual space so that
drivers don't have to abuse alloc_vm_area and open coded PTE manipulation
for it.
Link: https://lkml.kernel.org/r/20200918163724.2511-3-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/vmalloc.h | 1
mm/Kconfig | 3 ++
mm/vmalloc.c | 45 ++++++++++++++++++++++++++++++++++++++
3 files changed, 49 insertions(+)
--- a/include/linux/vmalloc.h~mm-add-a-vmap_pfn-function
+++ a/include/linux/vmalloc.h
@@ -121,6 +121,7 @@ extern void vfree_atomic(const void *add
extern void *vmap(struct page **pages, unsigned int count,
unsigned long flags, pgprot_t prot);
+void *vmap_pfn(unsigned long *pfns, unsigned int count, pgprot_t prot);
extern void vunmap(const void *addr);
extern int remap_vmalloc_range_partial(struct vm_area_struct *vma,
--- a/mm/Kconfig~mm-add-a-vmap_pfn-function
+++ a/mm/Kconfig
@@ -815,6 +815,9 @@ config DEVICE_PRIVATE
memory; i.e., memory that is only accessible from the device (or
group of devices). You likely also want to select HMM_MIRROR.
+config VMAP_PFN
+ bool
+
config FRAME_VECTOR
bool
--- a/mm/vmalloc.c~mm-add-a-vmap_pfn-function
+++ a/mm/vmalloc.c
@@ -2407,6 +2407,51 @@ void *vmap(struct page **pages, unsigned
}
EXPORT_SYMBOL(vmap);
+#ifdef CONFIG_VMAP_PFN
+struct vmap_pfn_data {
+ unsigned long *pfns;
+ pgprot_t prot;
+ unsigned int idx;
+};
+
+static int vmap_pfn_apply(pte_t *pte, unsigned long addr, void *private)
+{
+ struct vmap_pfn_data *data = private;
+
+ if (WARN_ON_ONCE(pfn_valid(data->pfns[data->idx])))
+ return -EINVAL;
+ *pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot));
+ return 0;
+}
+
+/**
+ * vmap_pfn - map an array of PFNs into virtually contiguous space
+ * @pfns: array of PFNs
+ * @count: number of pages to map
+ * @prot: page protection for the mapping
+ *
+ * Maps @count PFNs from @pfns into contiguous kernel virtual space and returns
+ * the start address of the mapping.
+ */
+void *vmap_pfn(unsigned long *pfns, unsigned int count, pgprot_t prot)
+{
+ struct vmap_pfn_data data = { .pfns = pfns, .prot = pgprot_nx(prot) };
+ struct vm_struct *area;
+
+ area = get_vm_area_caller(count * PAGE_SIZE, VM_IOREMAP,
+ __builtin_return_address(0));
+ if (!area)
+ return NULL;
+ if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
+ count * PAGE_SIZE, vmap_pfn_apply, &data)) {
+ free_vm_area(area);
+ return NULL;
+ }
+ return area->addr;
+}
+EXPORT_SYMBOL_GPL(vmap_pfn);
+#endif /* CONFIG_VMAP_PFN */
+
static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
pgprot_t prot, int node)
{
_
Patches currently in -mm which might be from hch@xxxxxx are
zsmalloc-switch-from-alloc_vm_area-to-get_vm_area.patch
mm-add-a-vmap_pfn-function.patch
drm-i915-use-vmap-in-shmem_pin_map.patch
drm-i915-use-vmap-in-i915_gem_object_map.patch
xen-xenbus-use-apply_to_page_range-directly-in-xenbus_map_ring_pv.patch
x86-xen-open-code-alloc_vm_area-in-arch_gnttab_valloc.patch
