blk-mq: fix kabi broken in struct request

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I57S8D
CVE: NA

--------------------------------

Since there are no reserved fields, declare a wrapper to fix kabi
broken.
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

block/blk-core.c

@@ -1293,17 +1293,18 @@ void blk_account_io_done(struct request *req, u64 now)
 		const int sgrp = op_stat_group(req_op(req));
 		struct hd_struct *part;
 		u64 stat_time;
+		struct request_wrapper *rq_wrapper = request_to_wrapper(req);
 
 		part_stat_lock();
 		part = req->part;
 		update_io_ticks(part, jiffies, true);
 		part_stat_inc(part, ios[sgrp]);
-		stat_time = READ_ONCE(req->stat_time_ns);
+		stat_time = READ_ONCE(rq_wrapper->stat_time_ns);
 		/*
-		 * This might fail if 'req->stat_time_ns' is updated
+		 * This might fail if 'stat_time_ns' is updated
 		 * in blk_mq_check_inflight_with_stat().
 		 */
-		if (likely(cmpxchg64(&req->stat_time_ns, stat_time, now)
+		if (likely(cmpxchg64(&rq_wrapper->stat_time_ns, stat_time, now)
 			   == stat_time)) {
 			u64 duation = stat_time ? now - stat_time :
 				now - req->start_time_ns;

block/blk-mq.c

@@ -111,17 +111,19 @@ static bool blk_mq_check_inflight_with_stat(struct blk_mq_hw_ctx *hctx,
 	if ((!mi->part->partno || rq->part == mi->part) &&
 	    blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT) {
 		u64 stat_time;
+		struct request_wrapper *rq_wrapper;
 
 		mi->inflight[rq_data_dir(rq)]++;
 		if (!rq->part)
 			return true;
 
-		stat_time = READ_ONCE(rq->stat_time_ns);
+		rq_wrapper = request_to_wrapper(rq);
+		stat_time = READ_ONCE(rq_wrapper->stat_time_ns);
 		/*
-		 * This might fail if 'req->stat_time_ns' is updated in
+		 * This might fail if 'stat_time_ns' is updated in
 		 * blk_account_io_done().
 		 */
-		if (likely(cmpxchg64(&rq->stat_time_ns, stat_time,
+		if (likely(cmpxchg64(&rq_wrapper->stat_time_ns, stat_time,
 				   rq->part->stat_time) == stat_time)) {
 			int sgrp = op_stat_group(req_op(rq));
 			u64 duation = stat_time ?
@@ -368,11 +370,11 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
 	rq->alloc_time_ns = alloc_time_ns;
 #endif
+	request_to_wrapper(rq)->stat_time_ns = 0;
 	if (blk_mq_need_time_stamp(rq))
 		rq->start_time_ns = ktime_get_ns();
 	else
 		rq->start_time_ns = 0;
-	rq->stat_time_ns = 0;
 	rq->io_start_time_ns = 0;
 	rq->stats_sectors = 0;
 	rq->nr_phys_segments = 0;
@@ -2555,7 +2557,7 @@ int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
 	 * rq_size is the size of the request plus driver payload, rounded
 	 * to the cacheline size
 	 */
-	rq_size = round_up(sizeof(struct request) + set->cmd_size,
+	rq_size = round_up(sizeof(struct request_wrapper) + set->cmd_size,
 				cache_line_size());
 	left = rq_size * depth;
 

include/linux/blk-mq.h

@@ -304,6 +304,15 @@ struct blk_mq_queue_data {
 	KABI_RESERVE(1)
 };
 
+struct request_wrapper {
+	struct request rq;
+
+	/* Time that I/O was counted in part_get_stat_info(). */
+	u64 stat_time_ns;
+};
+
+#define request_to_wrapper(_rq) container_of(_rq, struct request_wrapper, rq)
+
 typedef bool (busy_iter_fn)(struct blk_mq_hw_ctx *, struct request *, void *,
 		bool);
 typedef bool (busy_tag_iter_fn)(struct request *, void *, bool);
@@ -595,7 +604,7 @@ static inline bool blk_should_fake_timeout(struct request_queue *q)
  */
 static inline struct request *blk_mq_rq_from_pdu(void *pdu)
 {
-	return pdu - sizeof(struct request);
+	return pdu - sizeof(struct request_wrapper);
 }
 
 /**
@@ -609,7 +618,7 @@ static inline struct request *blk_mq_rq_from_pdu(void *pdu)
  */
 static inline void *blk_mq_rq_to_pdu(struct request *rq)
 {
-	return rq + 1;
+	return request_to_wrapper(rq) + 1;
 }
 
 static inline struct blk_mq_hw_ctx *queue_hctx(struct request_queue *q, int id)

include/linux/blkdev.h

@@ -207,8 +207,6 @@ struct request {
 	u64 start_time_ns;
 	/* Time that I/O was submitted to the device. */
 	u64 io_start_time_ns;
-	/* Time that I/O was counted in part_get_stat_info(). */
-	u64 stat_time_ns;
 #ifdef CONFIG_BLK_WBT
 	unsigned short wbt_flags;
 #endif