[Crash-utility] [PATCH] Handle blk_mq_ctx member changes for kernels v5.16-rc1~75^2~44

[Lianbo Jiang]

Kernel commit <9a14d6ce4135> ("block: remove debugfs blk_mq_ctx
dispatched/merged/completed attributes") removed the member
rq_dispatched and rq_completed from struct blk_mq_ctx. Without
this patch, crash will fail with the following error:

crash> dev -d
MAJOR GENDISK            NAME       REQUEST_QUEUE      TOTAL ASYNC  SYNC

dev: invalid structure member offset: blk_mq_ctx_rq_dispatched
     FILE: dev.c  LINE: 4229  FUNCTION: get_one_mctx_diskio()

Signed-off-by: Lianbo Jiang <lijiang at redhat.com>
---
 dev.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/dev.c b/dev.c
index effe789f38d8..dd21511e5dfc 100644
--- a/dev.c
+++ b/dev.c
@@ -4246,6 +4246,10 @@ get_mq_diskio(unsigned long q, unsigned long *mq_count)
 	unsigned long mctx_addr;
 	struct diskio tmp;
 
+	if (!MEMBER_EXISTS("blk_mq_ctx", "rq_dispatched") &&
+		!MEMBER_EXISTS("blk_mq_ctx", "rq_completed"))
+		return;
+
 	memset(&tmp, 0x00, sizeof(struct diskio));
 
 	readmem(q + OFFSET(request_queue_queue_ctx), KVADDR, &queue_ctx,
-- 
2.20.1