diff options
| -rw-r--r-- | include/linux/vmalloc.h | 4 | ||||
| -rw-r--r-- | mm/vmalloc.c | 53 |
2 files changed, 57 insertions, 0 deletions
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 132b260aef1..c2b10cae5da 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -70,6 +70,10 @@ extern int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages); extern void unmap_kernel_range(unsigned long addr, unsigned long size); +/* Allocate/destroy a 'vmalloc' VM area. */ +extern struct vm_struct *alloc_vm_area(size_t size); +extern void free_vm_area(struct vm_struct *area); + /* * Internals. Dont't use.. */ diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 8e05a11155c..3130c343088 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -767,3 +767,56 @@ EXPORT_SYMBOL(remap_vmalloc_range); void __attribute__((weak)) vmalloc_sync_all(void) { } + + +static int f(pte_t *pte, struct page *pmd_page, unsigned long addr, void *data) +{ + /* apply_to_page_range() does all the hard work. */ + return 0; +} + +/** + * alloc_vm_area - allocate a range of kernel address space + * @size: size of the area + * @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. + */ +struct vm_struct *alloc_vm_area(size_t size) +{ + struct vm_struct *area; + + area = get_vm_area(size, VM_IOREMAP); + if (area == NULL) + return NULL; + + /* + * This ensures that page tables are constructed for this region + * 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)) { + free_vm_area(area); + return NULL; + } + + /* Make sure the pagetables are constructed in process kernel + mappings */ + vmalloc_sync_all(); + + return area; +} +EXPORT_SYMBOL_GPL(alloc_vm_area); + +void free_vm_area(struct vm_struct *area) +{ + struct vm_struct *ret; + ret = remove_vm_area(area->addr); + BUG_ON(ret != area); + kfree(area); +} +EXPORT_SYMBOL_GPL(free_vm_area); |