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

Ryan Roberts
2024-10-14T11:53:26Z

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