net: convert sunrpc from pagevec to folio_batch

Remove the last usage of pagevecs.  There is a slight change here; we now
free the folio_batch as soon as it fills up instead of freeing the
folio_batch when we try to add a page to a full batch.  This should have
no effect in practice.

Link: https://lkml.kernel.org/r/20230621164557.3510324-10-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/sunrpc/svc.h

@@ -223,7 +223,7 @@ struct svc_rqst {
 	struct page *		*rq_next_page; /* next reply page to use */
 	struct page *		*rq_page_end;  /* one past the last page */
 
-	struct pagevec		rq_pvec;
+	struct folio_batch	rq_fbatch;
 	struct kvec		rq_vec[RPCSVC_MAXPAGES]; /* generally useful.. */
 	struct bio_vec		rq_bvec[RPCSVC_MAXPAGES];
 

net/sunrpc/svc.c

@@ -649,7 +649,7 @@ svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node)
 	if (!rqstp)
 		return rqstp;
 
-	pagevec_init(&rqstp->rq_pvec);
+	folio_batch_init(&rqstp->rq_fbatch);
 
 	__set_bit(RQ_BUSY, &rqstp->rq_flags);
 	rqstp->rq_server = serv;
@@ -860,9 +860,9 @@ bool svc_rqst_replace_page(struct svc_rqst *rqstp, struct page *page)
 	}
 
 	if (*rqstp->rq_next_page) {
-		if (!pagevec_space(&rqstp->rq_pvec))
-			__pagevec_release(&rqstp->rq_pvec);
-		pagevec_add(&rqstp->rq_pvec, *rqstp->rq_next_page);
+		if (!folio_batch_add(&rqstp->rq_fbatch,
+				page_folio(*rqstp->rq_next_page)))
+			__folio_batch_release(&rqstp->rq_fbatch);
 	}
 
 	get_page(page);
@@ -896,7 +896,7 @@ void svc_rqst_release_pages(struct svc_rqst *rqstp)
 void
 svc_rqst_free(struct svc_rqst *rqstp)
 {
-	pagevec_release(&rqstp->rq_pvec);
+	folio_batch_release(&rqstp->rq_fbatch);
 	svc_release_buffer(rqstp);
 	if (rqstp->rq_scratch_page)
 		put_page(rqstp->rq_scratch_page);