Commit eff042dd authored by Chuck Lever's avatar Chuck Lever
Browse files

sunrpc: Add a helper to derive maxpages from sv_max_mesg 



This page count is to be used to allocate various arrays of pages
and bio_vecs, replacing the fixed RPCSVC_MAXPAGES value.

The documenting comment is somewhat stale -- of course NFSv4
COMPOUND procedures may have multiple payloads.

Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Reviewed-by: default avatarNeilBrown <neil@brown.name>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 59243315

include/linux/sunrpc/svc.h

+17 −0
Original line number Diff line number Diff line
@@ -159,6 +159,23 @@ 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 count of pages 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.

 *

 * Each request/reply pair can have at most one "payload", plus two

 * pages, one for the request, and one for the reply.

 * nfsd_splice_actor() might need an extra page when a READ payload

 * is not page-aligned.

 */

static inline unsigned long svc_serv_maxpages(const struct svc_serv *serv)

{

	return DIV_ROUND_UP(serv->sv_max_mesg, PAGE_SIZE) + 2 + 1;

}



/*

 * The context of a single thread, including the request currently being

 * processed.