[RFC PATCH v1 21/57] sunrpc: Remove PAGE_SIZE compile-time constant assumption

[Ryan Roberts <ryan.roberts@arm.com>]

To prepare for supporting boot-time page size selection, refactor code
to remove assumptions about PAGE_SIZE being compile-time constant. Code
intended to be equivalent when compile-time page size is active.

Updated array sizes in various structs to contain enough entries for the
smallest supported page size.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---

***NOTE***
Any confused maintainers may want to read the cover note here for context:
https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/

 include/linux/sunrpc/svc.h      | 8 +++++---
 include/linux/sunrpc/svc_rdma.h | 4 ++--
 include/linux/sunrpc/svcsock.h  | 2 +-
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index a7d0406b9ef59..dda44018b8f36 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -160,6 +160,8 @@ extern u32 svc_max_payload(const struct svc_rqst *rqstp);
  */
 #define RPCSVC_MAXPAGES		((RPCSVC_MAXPAYLOAD+PAGE_SIZE-1)/PAGE_SIZE \
 				+ 2 + 1)
+#define RPCSVC_MAXPAGES_MAX	((RPCSVC_MAXPAYLOAD+PAGE_SIZE_MIN-1)/PAGE_SIZE_MIN \
+				+ 2 + 1)
 
 /*
  * The context of a single thread, including the request currently being
@@ -190,14 +192,14 @@ struct svc_rqst {
 	struct xdr_stream	rq_res_stream;
 	struct page		*rq_scratch_page;
 	struct xdr_buf		rq_res;
-	struct page		*rq_pages[RPCSVC_MAXPAGES + 1];
+	struct page		*rq_pages[RPCSVC_MAXPAGES_MAX + 1];
 	struct page *		*rq_respages;	/* points into rq_pages */
 	struct page *		*rq_next_page; /* next reply page to use */
 	struct page *		*rq_page_end;  /* one past the last page */
 
 	struct folio_batch	rq_fbatch;
-	struct kvec		rq_vec[RPCSVC_MAXPAGES]; /* generally useful.. */
-	struct bio_vec		rq_bvec[RPCSVC_MAXPAGES];
+	struct kvec		rq_vec[RPCSVC_MAXPAGES_MAX]; /* generally useful.. */
+	struct bio_vec		rq_bvec[RPCSVC_MAXPAGES_MAX];
 
 	__be32			rq_xid;		/* transmission id */
 	u32			rq_prog;	/* program number */
diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index d33bab33099ab..7c6441e8d6f7a 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -200,7 +200,7 @@ struct svc_rdma_recv_ctxt {
 	struct svc_rdma_pcl	rc_reply_pcl;
 
 	unsigned int		rc_page_count;
-	struct page		*rc_pages[RPCSVC_MAXPAGES];
+	struct page		*rc_pages[RPCSVC_MAXPAGES_MAX];
 };
 
 /*
@@ -242,7 +242,7 @@ struct svc_rdma_send_ctxt {
 	void			*sc_xprt_buf;
 	int			sc_page_count;
 	int			sc_cur_sge_no;
-	struct page		*sc_pages[RPCSVC_MAXPAGES];
+	struct page		*sc_pages[RPCSVC_MAXPAGES_MAX];
 	struct ib_sge		sc_sges[];
 };
 
diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index 7c78ec6356b92..6c6bcc82685a3 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/include/linux/sunrpc/svcsock.h
@@ -40,7 +40,7 @@ struct svc_sock {
 
 	struct completion	sk_handshake_done;
 
-	struct page *		sk_pages[RPCSVC_MAXPAGES];	/* received data */
+	struct page *		sk_pages[RPCSVC_MAXPAGES_MAX];	/* received data */
 };
 
 static inline u32 svc_sock_reclen(struct svc_sock *svsk)
-- 
2.43.0