rnbd/rtrs: Pass max segment size from blk user to the rdma library

When Block Device Layer is disabled, BLK_MAX_SEGMENT_SIZE is undefined.
The rtrs is a transport library and should compile independently of the
block layer. The desired max segment size should be passed down by the
user.

Introduce max_segment_size parameter for the rtrs_clt_open() call.

Fixes: f7a7a5c ("block/rnbd: client: main functionality")
Fixes: 6a98d71 ("RDMA/rtrs: client: main functionality")
Fixes: cb80329 ("RDMA/rtrs: client: private header with client structs and functions")
Fixes: b5c27cd ("RDMA/rtrs: public interface header to establish RDMA connections")
Link: https://lore.kernel.org/r/20200519111419.924170-1-danil.kipnis@cloud.ionos.com
Signed-off-by: Danil Kipnis <danil.kipnis@cloud.ionos.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/block/rnbd/rnbd-clt.c

@@ -1216,6 +1216,7 @@ find_and_get_or_create_sess(const char *sessname,
 				   paths, path_cnt, port_nr,
 				   sizeof(struct rnbd_iu),
 				   RECONNECT_DELAY, BMAX_SEGMENTS,
+				   BLK_MAX_SEGMENT_SIZE,
 				   MAX_RECONNECTS);
 	if (IS_ERR(sess->rtrs)) {
 		err = PTR_ERR(sess->rtrs);

drivers/infiniband/ulp/rtrs/rtrs-clt.c

@@ -12,7 +12,6 @@
 
 #include <linux/module.h>
 #include <linux/rculist.h>
-#include <linux/blkdev.h> /* for BLK_MAX_SEGMENT_SIZE */
 
 #include "rtrs-clt.h"
 #include "rtrs-log.h"
@@ -1406,7 +1405,8 @@ static void rtrs_clt_close_work(struct work_struct *work);
 
 static struct rtrs_clt_sess *alloc_sess(struct rtrs_clt *clt,
 					 const struct rtrs_addr *path,
-					 size_t con_num, u16 max_segments)
+					 size_t con_num, u16 max_segments,
+					 size_t max_segment_size)
 {
 	struct rtrs_clt_sess *sess;
 	int err = -ENOMEM;
@@ -1443,7 +1443,7 @@ static struct rtrs_clt_sess *alloc_sess(struct rtrs_clt *clt,
 	strlcpy(sess->s.sessname, clt->sessname, sizeof(sess->s.sessname));
 	sess->s.con_num = con_num;
 	sess->clt = clt;
-	sess->max_pages_per_mr = max_segments * BLK_MAX_SEGMENT_SIZE >> 12;
+	sess->max_pages_per_mr = max_segments * max_segment_size >> 12;
 	init_waitqueue_head(&sess->state_wq);
 	sess->state = RTRS_CLT_CONNECTING;
 	atomic_set(&sess->connected_cnt, 0);
@@ -2526,6 +2526,7 @@ static struct rtrs_clt *alloc_clt(const char *sessname, size_t paths_num,
 				  void	(*link_ev)(void *priv,
 						   enum rtrs_clt_link_ev ev),
 				  unsigned int max_segments,
+				  size_t max_segment_size,
 				  unsigned int reconnect_delay_sec,
 				  unsigned int max_reconnect_attempts)
 {
@@ -2555,6 +2556,7 @@ static struct rtrs_clt *alloc_clt(const char *sessname, size_t paths_num,
 	clt->port = port;
 	clt->pdu_sz = pdu_sz;
 	clt->max_segments = max_segments;
+	clt->max_segment_size = max_segment_size;
 	clt->reconnect_delay_sec = reconnect_delay_sec;
 	clt->max_reconnect_attempts = max_reconnect_attempts;
 	clt->priv = priv;
@@ -2636,6 +2638,7 @@ static void free_clt(struct rtrs_clt *clt)
  * @pdu_sz: Size of extra payload which can be accessed after permit allocation.
  * @reconnect_delay_sec: time between reconnect tries
  * @max_segments: Max. number of segments per IO request
+ * @max_segment_size: Max. size of one segment
  * @max_reconnect_attempts: Number of times to reconnect on error before giving
  *			    up, 0 for * disabled, -1 for forever
  *
@@ -2650,6 +2653,7 @@ struct rtrs_clt *rtrs_clt_open(struct rtrs_clt_ops *ops,
 				 size_t paths_num, u16 port,
 				 size_t pdu_sz, u8 reconnect_delay_sec,
 				 u16 max_segments,
+				 size_t max_segment_size,
 				 s16 max_reconnect_attempts)
 {
 	struct rtrs_clt_sess *sess, *tmp;
@@ -2658,7 +2662,7 @@ struct rtrs_clt *rtrs_clt_open(struct rtrs_clt_ops *ops,
 
 	clt = alloc_clt(sessname, paths_num, port, pdu_sz, ops->priv,
 			ops->link_ev,
-			max_segments, reconnect_delay_sec,
+			max_segments, max_segment_size, reconnect_delay_sec,
 			max_reconnect_attempts);
 	if (IS_ERR(clt)) {
 		err = PTR_ERR(clt);
@@ -2668,7 +2672,7 @@ struct rtrs_clt *rtrs_clt_open(struct rtrs_clt_ops *ops,
 		struct rtrs_clt_sess *sess;
 
 		sess = alloc_sess(clt, &paths[i], nr_cpu_ids,
-				  max_segments);
+				  max_segments, max_segment_size);
 		if (IS_ERR(sess)) {
 			err = PTR_ERR(sess);
 			goto close_all_sess;
@@ -2917,7 +2921,8 @@ int rtrs_clt_create_path_from_sysfs(struct rtrs_clt *clt,
 	struct rtrs_clt_sess *sess;
 	int err;
 
-	sess = alloc_sess(clt, addr, nr_cpu_ids, clt->max_segments);
+	sess = alloc_sess(clt, addr, nr_cpu_ids, clt->max_segments,
+			  clt->max_segment_size);
 	if (IS_ERR(sess))
 		return PTR_ERR(sess);
 

drivers/infiniband/ulp/rtrs/rtrs-clt.h

@@ -164,6 +164,7 @@ struct rtrs_clt {
 	unsigned int		max_reconnect_attempts;
 	unsigned int		reconnect_delay_sec;
 	unsigned int		max_segments;
+	size_t			max_segment_size;
 	void			*permits;
 	unsigned long		*permits_map;
 	size_t			queue_depth;

drivers/infiniband/ulp/rtrs/rtrs.h

@@ -58,6 +58,7 @@ struct rtrs_clt *rtrs_clt_open(struct rtrs_clt_ops *ops,
 				 size_t path_cnt, u16 port,
 				 size_t pdu_sz, u8 reconnect_delay_sec,
 				 u16 max_segments,
+				 size_t max_segment_size,
 				 s16 max_reconnect_attempts);
 
 void rtrs_clt_close(struct rtrs_clt *sess);