Commit dad0d91c authored by Uladzislau Rezki (Sony)'s avatar Uladzislau Rezki (Sony) Committed by Herbert Xu
Browse files

mm/slab: Add kvfree_atomic() helper 



kvmalloc() now supports non-sleeping GFP flags, including
the vmalloc fallback path. This means it may return vmalloc
memory even for GFP_ATOMIC and GFP_NOWAIT allocations.

Freeing such memory with kvfree() may then end up calling
vfree(), which is not safe for non-sleeping contexts.

Introduce kvfree_atomic() helper for such cases. It mirrors
kvfree(), but uses vfree_atomic() for vmalloced memory.

Signed-off-by: default avatarUladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: default avatarVlastimil Babka (SUSE) <vbabka@kernel.org>
Acked-by: default avatarHarry Yoo (Oracle) <harry@kernel.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 09ae540e

include/linux/slab.h

+3 −0
Original line number Diff line number Diff line
@@ -1234,6 +1234,9 @@ void *kvrealloc_node_align_noprof(const void *p, size_t size, unsigned long alig 
extern void kvfree(const void *addr);

DEFINE_FREE(kvfree, void *, if (!IS_ERR_OR_NULL(_T)) kvfree(_T))



extern void kvfree_atomic(const void *addr);

DEFINE_FREE(kvfree_atomic, void *, if (!IS_ERR_OR_NULL(_T)) kvfree_atomic(_T))



extern void kvfree_sensitive(const void *addr, size_t len);



unsigned int kmem_cache_size(struct kmem_cache *s);

mm/slub.c

+16 −0
Original line number Diff line number Diff line
@@ -6882,6 +6882,22 @@ void kvfree(const void *addr) 
}

EXPORT_SYMBOL(kvfree);



/**

 * kvfree_atomic() - Free memory.

 * @addr: Pointer to allocated memory.

 *

 * Same as kvfree(), but uses vfree_atomic() for vmalloc

 * backed memory. Must not be called from NMI context.

 */

void kvfree_atomic(const void *addr)

{

	if (is_vmalloc_addr(addr))

		vfree_atomic(addr);

	else

		kfree(addr);

}

EXPORT_SYMBOL(kvfree_atomic);



/**

 * kvfree_sensitive - Free a data object containing sensitive information.

 * @addr: address of the data object to be freed.