Re: [PATCH -next] NFSD: Use struct_size() helpler in alloc_session()

[Jeff Layton <jlayton@kernel.org>]

On Fri, 2022-11-11 at 17:18 +0800, Xiu Jianfeng wrote:
> Use struct_size() helper to simplify the code, no functional changes.
> 
> Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
> ---
>  fs/nfsd/nfs4state.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 2ec981fd2985..97badca3135e 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1833,13 +1833,12 @@ static struct nfsd4_session *alloc_session(struct nfsd4_channel_attrs *fattrs,
>  	int numslots = fattrs->maxreqs;
>  	int slotsize = slot_bytes(fattrs);
>  	struct nfsd4_session *new;
> -	int mem, i;
> +	int i;
>  
> -	BUILD_BUG_ON(NFSD_MAX_SLOTS_PER_SESSION * sizeof(struct nfsd4_slot *)
> -			+ sizeof(struct nfsd4_session) > PAGE_SIZE);
> -	mem = numslots * sizeof(struct nfsd4_slot *);
> +	BUILD_BUG_ON(struct_size(new, se_slots, NFSD_MAX_SLOTS_PER_SESSION)
> +		     > PAGE_SIZE);
>  
> -	new = kzalloc(sizeof(*new) + mem, GFP_KERNEL);
> +	new = kzalloc(struct_size(new, se_slots, numslots), GFP_KERNEL);
>  	if (!new)
>  		return NULL;
>  	/* allocate each struct nfsd4_slot and data cache in one piece */

Reviewed-by: Jeff Layton <jlayton@kernel.org>