From: Matthew Wilcox <[email protected]> free() can free many different kinds of memory.
Signed-off-by: Matthew Wilcox <[email protected]> --- include/linux/kernel.h | 2 ++ mm/util.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 41 insertions(+) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3fd291503576..8bb578938e65 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -933,6 +933,8 @@ static inline void ftrace_dump(enum ftrace_dump_mode oops_dump_mode) { } "pointer type mismatch in container_of()"); \ ((type *)(__mptr - offsetof(type, member))); }) +void free(const void *); + /* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */ #ifdef CONFIG_FTRACE_MCOUNT_RECORD # define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD diff --git a/mm/util.c b/mm/util.c index dc4c7b551aaf..8aa2071059b0 100644 --- a/mm/util.c +++ b/mm/util.c @@ -26,6 +26,45 @@ static inline int is_kernel_rodata(unsigned long addr) addr < (unsigned long)__end_rodata; } +/** + * free() - Free memory + * @ptr: Pointer to memory + * + * This function can free almost any type of memory. It can safely be + * called on: + * * NULL pointers. + * * Pointers to read-only data (will do nothing). + * * Pointers to memory allocated from kmalloc(). + * * Pointers to memory allocated from kmem_cache_alloc(). + * * Pointers to memory allocated from vmalloc(). + * * Pointers to memory allocated from alloc_percpu(). + * * Pointers to memory allocated from __get_free_pages(). + * * Pointers to memory allocated from page_frag_alloc(). + * + * It cannot free memory allocated by dma_pool_alloc() or dma_alloc_coherent(). + */ +void free(const void *ptr) +{ + struct page *page; + + if (unlikely(ZERO_OR_NULL_PTR(ptr))) + return; + if (is_kernel_rodata((unsigned long)ptr)) + return; + + page = virt_to_head_page(ptr); + if (likely(PageSlab(page))) + return kmem_cache_free(page->slab_cache, (void *)ptr); + + if (is_vmalloc_addr(ptr)) + return vfree(ptr); + if (is_kernel_percpu_address((unsigned long)ptr)) + free_percpu((void __percpu *)ptr); + if (put_page_testzero(page)) + __put_page(page); +} +EXPORT_SYMBOL(free); + /** * kfree_const - conditionally free memory * @x: pointer to the memory -- 2.16.2
