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author | David Vrabel <david.vrabel@citrix.com> | 2011-09-29 16:53:32 +0100 |
---|---|---|
committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2011-11-16 12:13:08 -0500 |
commit | cd12909cb576d37311fe35868780e82d5007d0c8 (patch) | |
tree | 70ec60af4feb32087f542a838fe4dce8717f0cd6 /mm/vmalloc.c | |
parent | 1ea6b8f48918282bdca0b32a34095504ee65bab5 (diff) | |
download | blackbird-obmc-linux-cd12909cb576d37311fe35868780e82d5007d0c8.tar.gz blackbird-obmc-linux-cd12909cb576d37311fe35868780e82d5007d0c8.zip |
xen: map foreign pages for shared rings by updating the PTEs directly
When mapping a foreign page with xenbus_map_ring_valloc() with the
GNTTABOP_map_grant_ref hypercall, set the GNTMAP_contains_pte flag and
pass a pointer to the PTE (in init_mm).
After the page is mapped, the usual fault mechanism can be used to
update additional MMs. This allows the vmalloc_sync_all() to be
removed from alloc_vm_area().
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
[v1: Squashed fix by Michal for no-mmu case]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>
Diffstat (limited to 'mm/vmalloc.c')
-rw-r--r-- | mm/vmalloc.c | 27 |
1 files changed, 13 insertions, 14 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index b669aa6f6caf..3231bf332878 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2141,23 +2141,30 @@ void __attribute__((weak)) vmalloc_sync_all(void) static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data) { - /* apply_to_page_range() does all the hard work. */ + pte_t ***p = data; + + if (p) { + *(*p) = pte; + (*p)++; + } return 0; } /** * alloc_vm_area - allocate a range of kernel address space * @size: size of the area + * @ptes: returns the PTEs for the address space * * Returns: NULL on failure, vm_struct on success * * This function reserves a range of kernel address space, and * allocates pagetables to map that range. No actual mappings - * are created. If the kernel address space is not shared - * between processes, it syncs the pagetable across all - * processes. + * are created. + * + * If @ptes is non-NULL, pointers to the PTEs (in init_mm) + * allocated for the VM area are returned. */ -struct vm_struct *alloc_vm_area(size_t size) +struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes) { struct vm_struct *area; @@ -2171,19 +2178,11 @@ struct vm_struct *alloc_vm_area(size_t size) * of kernel virtual address space and mapped into init_mm. */ if (apply_to_page_range(&init_mm, (unsigned long)area->addr, - area->size, f, NULL)) { + size, f, ptes ? &ptes : NULL)) { free_vm_area(area); return NULL; } - /* - * If the allocated address space is passed to a hypercall - * before being used then we cannot rely on a page fault to - * trigger an update of the page tables. So sync all the page - * tables here. - */ - vmalloc_sync_all(); - return area; } EXPORT_SYMBOL_GPL(alloc_vm_area); |