The sbitmap_queue.min_shallow_depth member was added by kernel commit
a327553965de ("sbitmap: fix missed wakeups caused by 
sbitmap_queue_get_shallow()")
at Linux 4.18.  Without the patch, on earlier kernels the "sbitmapq"
command fails with the following error:

  crash> sbitmapq ffff89bb7638ee50

  sbitmapq: invalid structure member offset: sbitmap_queue_min_shallow_depth
            FILE: sbitmap.c  LINE: 398  FUNCTION: sbitmap_queue_context_load()

Signed-off-by: Kazuhito Hagio <[email protected]>
---
 sbitmap.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sbitmap.c b/sbitmap.c
index c8c9f2b6d003..500246ec6bea 100644
--- a/sbitmap.c
+++ b/sbitmap.c
@@ -371,7 +371,8 @@ static void sbitmap_queue_show(const struct 
sbitmap_queue_context *sqc,
        else if (VALID_MEMBER(sbitmap_round_robin)) /* 5.13 and later */
                fprintf(fp, "round_robin = %d\n", sc->round_robin);
 
-       fprintf(fp, "min_shallow_depth = %u\n", sqc->min_shallow_depth);
+       if (VALID_MEMBER(sbitmap_queue_min_shallow_depth)) /* 4.18 and later */
+               fprintf(fp, "min_shallow_depth = %u\n", sqc->min_shallow_depth);
 }
 
 static void sbitmap_queue_context_load(ulong addr, struct 
sbitmap_queue_context *sqc)
@@ -395,7 +396,8 @@ static void sbitmap_queue_context_load(ulong addr, struct 
sbitmap_queue_context
                sqc->ws_active = INT(sbitmap_queue_buf + 
OFFSET(sbitmap_queue_ws_active));
        if (VALID_MEMBER(sbitmap_queue_round_robin))
                sqc->round_robin = BOOL(sbitmap_queue_buf + 
OFFSET(sbitmap_queue_round_robin));
-       sqc->min_shallow_depth = UINT(sbitmap_queue_buf + 
OFFSET(sbitmap_queue_min_shallow_depth));
+       if (VALID_MEMBER(sbitmap_queue_min_shallow_depth))
+               sqc->min_shallow_depth = UINT(sbitmap_queue_buf + 
OFFSET(sbitmap_queue_min_shallow_depth));
 
        FREEBUF(sbitmap_queue_buf);
 }
-- 
2.27.0

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