On Sun, 20 Apr 2025, cel@xxxxxxxxxx wrote:
> From: Chuck Lever <chuck.lever@xxxxxxxxxx>
>
> This page count is to be used to allocate various arrays of pages,
> bio_vecs, and kvecs, replacing the fixed RPCSVC_MAXPAGES value.
>
> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> ---
> include/linux/sunrpc/svc.h | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
> index 74658cca0f38..5b879c31d7b8 100644
> --- a/include/linux/sunrpc/svc.h
> +++ b/include/linux/sunrpc/svc.h
> @@ -159,6 +159,18 @@ extern u32 svc_max_payload(const struct svc_rqst *rqstp);
> #define RPCSVC_MAXPAGES ((RPCSVC_MAXPAYLOAD+PAGE_SIZE-1)/PAGE_SIZE \
> + 2 + 1)
>
> +/**
> + * svc_serv_maxpages - maximum pages/kvecs needed for one RPC message
> + * @serv: RPC service context
> + *
> + * Returns a count of pages or vectors that can hold the maximum
> + * size RPC message for @serv.
> + */
> +static inline unsigned long svc_serv_maxpages(const struct svc_serv *serv)
> +{
> + return ((serv->sv_max_mesg + PAGE_SIZE - 1) >> PAGE_SHIFT) + 2 + 1;
> +}
> +
This looks like it should be
DIV_ROUND_UP(serv->sv_max_mesg, PAGE_SIZE) + 2
Could we document what the "+ 2" is for??
Thanks,
NeilBrown
> /*
> * The context of a single thread, including the request currently being
> * processed.
> --
> 2.49.0
>
>
