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mm/slab: move kmalloc_slab() to mm/slab.h 

In preparation for the next patch, move the kmalloc_slab() function to
the header, as it will have callers from two files, and make it inline.
To avoid unnecessary bloat, remove all size checks/warnings from
kmalloc_slab() as they just duplicate those in callers, especially after
recent changes to kmalloc_size_roundup(). We just need to adjust handling
of zero size in __do_kmalloc_node(). Also we can stop handling NULL
result from kmalloc_slab() there as that now cannot happen (unless
called too early during boot).

The size_index array becomes visible so rename it to a more specific
kmalloc_size_index.

Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
This commit is contained in:
Vlastimil Babka 2023-11-13 12:02:02 +01:00
parent b774d3e326
commit 5a9d31d980
2 changed files with 34 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
mm/slab.h
View File

@ -389,8 +389,32 @@ extern const struct kmalloc_info_struct {
void setup_kmalloc_cache_index_table(void);
void create_kmalloc_caches(slab_flags_t);
/* Find the kmalloc slab corresponding for a certain size */
struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags, unsigned long caller);
extern u8 kmalloc_size_index[24];
static inline unsigned int size_index_elem(unsigned int bytes)
{
return (bytes - 1) / 8;
}
/*
* Find the kmem_cache structure that serves a given size of
* allocation
*
* This assumes size is larger than zero and not larger than
* KMALLOC_MAX_CACHE_SIZE and the caller must check that.
*/
static inline struct kmem_cache *
kmalloc_slab(size_t size, gfp_t flags, unsigned long caller)
{
unsigned int index;
if (size <= 192)
index = kmalloc_size_index[size_index_elem(size)];
else
index = fls(size - 1);
return kmalloc_caches[kmalloc_type(flags, caller)][index];
}
void *__kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags,
int node, size_t orig_size,

43
mm/slab_common.c
View File

@ -665,7 +665,7 @@ EXPORT_SYMBOL(random_kmalloc_seed);
* of two cache sizes there. The size of larger slabs can be determined using
* fls.
*/
static u8 size_index[24] __ro_after_init = {
u8 kmalloc_size_index[24] __ro_after_init = {
3, /* 8 */
4, /* 16 */
5, /* 24 */
@ -692,33 +692,6 @@ static u8 size_index[24] __ro_after_init = {
2 /* 192 */
};
static inline unsigned int size_index_elem(unsigned int bytes)
{
return (bytes - 1) / 8;
}
/*
* Find the kmem_cache structure that serves a given size of
* allocation
*/
struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags, unsigned long caller)
{
unsigned int index;
if (size <= 192) {
if (!size)
return ZERO_SIZE_PTR;
index = size_index[size_index_elem(size)];
} else {
if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE))
return NULL;
index = fls(size - 1);
}
return kmalloc_caches[kmalloc_type(flags, caller)][index];
}
size_t kmalloc_size_roundup(size_t size)
{
if (size && size <= KMALLOC_MAX_CACHE_SIZE) {
@ -843,9 +816,9 @@ void __init setup_kmalloc_cache_index_table(void)
for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
unsigned int elem = size_index_elem(i);
if (elem >= ARRAY_SIZE(size_index))
if (elem >= ARRAY_SIZE(kmalloc_size_index))
break;
size_index[elem] = KMALLOC_SHIFT_LOW;
kmalloc_size_index[elem] = KMALLOC_SHIFT_LOW;
}
if (KMALLOC_MIN_SIZE >= 64) {
@ -854,7 +827,7 @@ void __init setup_kmalloc_cache_index_table(void)
* is 64 byte.
*/
for (i = 64 + 8; i <= 96; i += 8)
size_index[size_index_elem(i)] = 7;
kmalloc_size_index[size_index_elem(i)] = 7;
}
@ -865,7 +838,7 @@ void __init setup_kmalloc_cache_index_table(void)
* instead.
*/
for (i = 128 + 8; i <= 192; i += 8)
size_index[size_index_elem(i)] = 8;
kmalloc_size_index[size_index_elem(i)] = 8;
}
}
@ -977,10 +950,10 @@ void *__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller
return ret;
}
s = kmalloc_slab(size, flags, caller);
if (unlikely(!size))
return ZERO_SIZE_PTR;
if (unlikely(ZERO_OR_NULL_PTR(s)))
return s;
s = kmalloc_slab(size, flags, caller);
ret = __kmem_cache_alloc_node(s, flags, node, size, caller);
ret = kasan_kmalloc(s, ret, size, flags);