The patch titled
Subject: drm/i915: use vmap in shmem_pin_map
has been added to the -mm tree. Its filename is
drm-i915-use-vmap-in-shmem_pin_map.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/drm-i915-use-vmap-in-shmem_pin_map.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/drm-i915-use-vmap-in-shmem_pin_map.patch
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------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: drm/i915: use vmap in shmem_pin_map
shmem_pin_map somewhat awkwardly reimplements vmap using alloc_vm_area and
manual pte setup. The only practical difference is that alloc_vm_area
prefeaults the vmalloc area PTEs, which doesn't seem to be required here
(and could be added to vmap using a flag if actually required).
Link: https://lkml.kernel.org/r/20200918163724.2511-4-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gt/shmem_utils.c | 90 ++++++++++--------------
1 file changed, 38 insertions(+), 52 deletions(-)
--- a/drivers/gpu/drm/i915/gt/shmem_utils.c~drm-i915-use-vmap-in-shmem_pin_map
+++ a/drivers/gpu/drm/i915/gt/shmem_utils.c
@@ -49,80 +49,66 @@ struct file *shmem_create_from_object(st
return file;
}
-static size_t shmem_npte(struct file *file)
+static size_t shmem_npages(struct file *file)
{
return file->f_mapping->host->i_size >> PAGE_SHIFT;
}
-static void __shmem_unpin_map(struct file *file, void *ptr, size_t n_pte)
-{
- unsigned long pfn;
-
- vunmap(ptr);
-
- for (pfn = 0; pfn < n_pte; pfn++) {
- struct page *page;
-
- page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
- GFP_KERNEL);
- if (!WARN_ON(IS_ERR(page))) {
- put_page(page);
- put_page(page);
- }
- }
-}
-
void *shmem_pin_map(struct file *file)
{
- const size_t n_pte = shmem_npte(file);
- pte_t *stack[32], **ptes, **mem;
- struct vm_struct *area;
- unsigned long pfn;
-
- mem = stack;
- if (n_pte > ARRAY_SIZE(stack)) {
- mem = kvmalloc_array(n_pte, sizeof(*mem), GFP_KERNEL);
- if (!mem)
+ const size_t n_pages = shmem_npages(file);
+ struct page **pages, *stack[32];
+ void *vaddr;
+ long i;
+
+ pages = stack;
+ if (n_pages > ARRAY_SIZE(stack)) {
+ pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
+ if (!pages)
return NULL;
}
- area = alloc_vm_area(n_pte << PAGE_SHIFT, mem);
- if (!area) {
- if (mem != stack)
- kvfree(mem);
- return NULL;
- }
-
- ptes = mem;
- for (pfn = 0; pfn < n_pte; pfn++) {
- struct page *page;
-
- page = shmem_read_mapping_page_gfp(file->f_mapping, pfn,
- GFP_KERNEL);
- if (IS_ERR(page))
+ for (i = 0; i < n_pages; i++) {
+ pages[i] = shmem_read_mapping_page_gfp(file->f_mapping, i,
+ GFP_KERNEL);
+ if (IS_ERR(pages[i]))
goto err_page;
-
- **ptes++ = mk_pte(page, PAGE_KERNEL);
}
- if (mem != stack)
- kvfree(mem);
+ vaddr = vmap(pages, n_pages, 0, PAGE_KERNEL);
+ if (!vaddr)
+ goto err_page;
+ if (pages != stack)
+ kvfree(pages);
mapping_set_unevictable(file->f_mapping);
- return area->addr;
+ return vaddr;
err_page:
- if (mem != stack)
- kvfree(mem);
-
- __shmem_unpin_map(file, area->addr, pfn);
+ while (--i >= 0)
+ put_page(pages[i]);
+ if (pages != stack)
+ kvfree(pages);
return NULL;
}
void shmem_unpin_map(struct file *file, void *ptr)
{
+ long i = shmem_npages(file);
+
mapping_clear_unevictable(file->f_mapping);
- __shmem_unpin_map(file, ptr, shmem_npte(file));
+ vunmap(ptr);
+
+ for (i = 0; i < shmem_npages(file); i++) {
+ struct page *page;
+
+ page = shmem_read_mapping_page_gfp(file->f_mapping, i,
+ GFP_KERNEL);
+ if (!WARN_ON(IS_ERR(page))) {
+ put_page(page);
+ put_page(page);
+ }
+ }
}
static int __shmem_rw(struct file *file, loff_t off,
_
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
