Re: [PATCH 1/1] mm: change inlined allocation helpers to account at the call site

Matthew Wilcox
2024-04-04T17:04:46Z

On Thu, Apr 04, 2024 at 09:54:04AM -0700, Suren Baghdasaryan wrote:
> +++ b/include/linux/dma-fence-chain.h
> @@ -86,10 +86,7 @@ dma_fence_chain_contained(struct dma_fence *fence)
> *
> * Returns a new struct dma_fence_chain object or NULL on failure.
> */
> -static inline struct dma_fence_chain *dma_fence_chain_alloc(void)
> -{
> - return kmalloc(sizeof(struct dma_fence_chain), GFP_KERNEL);
> -};
> +#define dma_fence_chain_alloc() kmalloc(sizeof(struct dma_fence_chain), GFP_KERNEL)

You've removed some typesafety here. Before, if I wrote:

struct page *page = dma_fence_chain_alloc();

the compiler would warn me that I've done something stupid. Now it
can't tell. Suggest perhaps:

#define dma_fence_chain_alloc() \
(struct dma_fence_chain *)kmalloc(sizeof(struct dma_fence_chain), \
GFP_KERNEL)

but maybe there's a better way of doing that. There are a few other
occurrences of the same problem in this monster patch.

> +++ b/include/linux/hid_bpf.h
> @@ -149,10 +149,7 @@ static inline int hid_bpf_connect_device(struct hid_device *hdev) { return 0; }
> static inline void hid_bpf_disconnect_device(struct hid_device *hdev) {}
> static inline void hid_bpf_destroy_device(struct hid_device *hid) {}
> static inline void hid_bpf_device_init(struct hid_device *hid) {}
> -static inline u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size)
> -{
> - return kmemdup(rdesc, *size, GFP_KERNEL);
> -}
> +#define call_hid_bpf_rdesc_fixup(_hdev, _rdesc, _size) kmemdup(_rdesc, *(_size), GFP_KERNEL)

here

> -static inline handle_t *jbd2_alloc_handle(gfp_t gfp_flags)
> -{
> - return kmem_cache_zalloc(jbd2_handle_cache, gfp_flags);
> -}
> +#define jbd2_alloc_handle(_gfp_flags) kmem_cache_zalloc(jbd2_handle_cache, _gfp_flags)

here

> +++ b/include/linux/skmsg.h
> @@ -410,11 +410,8 @@ void sk_psock_stop_verdict(struct sock *sk, struct sk_psock *psock);
> int sk_psock_msg_verdict(struct sock *sk, struct sk_psock *psock,
> struct sk_msg *msg);
>
> -static inline struct sk_psock_link *sk_psock_init_link(void)
> -{
> - return kzalloc(sizeof(struct sk_psock_link),
> - GFP_ATOMIC | __GFP_NOWARN);
> -}
> +#define sk_psock_init_link() \
> + kzalloc(sizeof(struct sk_psock_link), GFP_ATOMIC | __GFP_NOWARN)

here

... I kind of gave up at this point. You'll want to audit for yourself
anyway ;-)