diff options
Diffstat (limited to 'mm/util.c')
| -rw-r--r-- | mm/util.c | 48 |
1 files changed, 40 insertions, 8 deletions
@@ -12,10 +12,30 @@ #include <linux/hugetlb.h> #include <linux/vmalloc.h> +#include <asm/sections.h> #include <asm/uaccess.h> #include "internal.h" +static inline int is_kernel_rodata(unsigned long addr) +{ + return addr >= (unsigned long)__start_rodata && + addr < (unsigned long)__end_rodata; +} + +/** + * kfree_const - conditionally free memory + * @x: pointer to the memory + * + * Function calls kfree only if @x is not in .rodata section. + */ +void kfree_const(const void *x) +{ + if (!is_kernel_rodata((unsigned long)x)) + kfree(x); +} +EXPORT_SYMBOL(kfree_const); + /** * kstrdup - allocate space for and copy an existing string * @s: the string to duplicate @@ -38,6 +58,24 @@ char *kstrdup(const char *s, gfp_t gfp) EXPORT_SYMBOL(kstrdup); /** + * kstrdup_const - conditionally duplicate an existing const string + * @s: the string to duplicate + * @gfp: the GFP mask used in the kmalloc() call when allocating memory + * + * Function returns source string if it is in .rodata section otherwise it + * fallbacks to kstrdup. + * Strings allocated by kstrdup_const should be freed by kfree_const. + */ +const char *kstrdup_const(const char *s, gfp_t gfp) +{ + if (is_kernel_rodata((unsigned long)s)) + return s; + + return kstrdup(s, gfp); +} +EXPORT_SYMBOL(kstrdup_const); + +/** * kstrndup - allocate space for and copy an existing string * @s: the string to duplicate * @max: read at most @max chars from @s @@ -240,14 +278,8 @@ int __weak get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages) { struct mm_struct *mm = current->mm; - int ret; - - down_read(&mm->mmap_sem); - ret = get_user_pages(current, mm, start, nr_pages, - write, 0, pages, NULL); - up_read(&mm->mmap_sem); - - return ret; + return get_user_pages_unlocked(current, mm, start, nr_pages, + write, 0, pages); } EXPORT_SYMBOL_GPL(get_user_pages_fast); |