diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/util.c | 26 | ||||
| -rw-r--r-- | mm/vmalloc.c | 53 |
2 files changed, 77 insertions, 2 deletions
@@ -6,7 +6,6 @@ /** * kstrdup - allocate space for and copy an existing string - * * @s: the string to duplicate * @gfp: the GFP mask used in the kmalloc() call when allocating memory */ @@ -27,6 +26,30 @@ char *kstrdup(const char *s, gfp_t gfp) EXPORT_SYMBOL(kstrdup); /** + * kstrndup - allocate space for and copy an existing string + * @s: the string to duplicate + * @max: read at most @max chars from @s + * @gfp: the GFP mask used in the kmalloc() call when allocating memory + */ +char *kstrndup(const char *s, size_t max, gfp_t gfp) +{ + size_t len; + char *buf; + + if (!s) + return NULL; + + len = strnlen(s, max); + buf = kmalloc_track_caller(len+1, gfp); + if (buf) { + memcpy(buf, s, len); + buf[len] = '\0'; + } + return buf; +} +EXPORT_SYMBOL(kstrndup); + +/** * kmemdup - duplicate region of memory * * @src: memory region to duplicate @@ -80,7 +103,6 @@ EXPORT_SYMBOL(krealloc); /* * strndup_user - duplicate an existing string from user space - * * @s: The string to duplicate * @n: Maximum number of bytes to copy, including the trailing NUL. */ diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 8e05a11..3130c34 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); |