The sbitmap_word.cleared member was added by kernel commit ea86ea2cdced
("sbitmap: ammortize cost of clearing bits") at Linux 5.0. Without the
patch, on earlier kernels the "sbitmapq" command fails with the
following error:
crash> sbitmapq ffff8f1a3611cf10
sbitmapq: invalid structure member offset: sbitmap_word_cleared
FILE: sbitmap.c LINE: 92 FUNCTION: __sbitmap_weight()
Signed-off-by: Kazuhito Hagio <[email protected]>
---
sbitmap.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)
diff --git a/sbitmap.c b/sbitmap.c
index 37db21d15219..c8c9f2b6d003 100644
--- a/sbitmap.c
+++ b/sbitmap.c
@@ -89,7 +89,6 @@ static unsigned int __sbitmap_weight(const struct
sbitmap_context *sc, bool set)
{
const ulong sbitmap_word_size = SIZE(sbitmap_word);
const ulong w_word_off = OFFSET(sbitmap_word_word);
- const ulong w_cleared_off = OFFSET(sbitmap_word_cleared);
unsigned int weight = 0;
ulong addr = sc->map_addr;
@@ -111,7 +110,10 @@ static unsigned int __sbitmap_weight(const struct
sbitmap_context *sc, bool set)
word = ULONG(sbitmap_word_buf + w_word_off);
weight += bitmap_weight(word, depth);
} else {
- cleared = ULONG(sbitmap_word_buf + w_cleared_off);
+ if (VALID_MEMBER(sbitmap_word_cleared))
+ cleared = ULONG(sbitmap_word_buf +
OFFSET(sbitmap_word_cleared));
+ else
+ cleared = 0;
weight += bitmap_weight(cleared, depth);
}
@@ -130,7 +132,10 @@ static unsigned int sbitmap_weight(const struct
sbitmap_context *sc)
static unsigned int sbitmap_cleared(const struct sbitmap_context *sc)
{
- return __sbitmap_weight(sc, false);
+ if (VALID_MEMBER(sbitmap_word_cleared)) /* 5.0 and later */
+ return __sbitmap_weight(sc, false);
+ else
+ return 0;
}
static void sbitmap_emit_byte(unsigned int offset, uint8_t byte)
@@ -149,7 +154,6 @@ static void sbitmap_bitmap_show(const struct
sbitmap_context *sc)
{
const ulong sbitmap_word_size = SIZE(sbitmap_word);
const ulong w_word_off = OFFSET(sbitmap_word_word);
- const ulong w_cleared_off = OFFSET(sbitmap_word_cleared);
uint8_t byte = 0;
unsigned int byte_bits = 0;
@@ -169,7 +173,10 @@ static void sbitmap_bitmap_show(const struct
sbitmap_context *sc)
}
word = ULONG(sbitmap_word_buf + w_word_off);
- cleared = ULONG(sbitmap_word_buf + w_cleared_off);
+ if (VALID_MEMBER(sbitmap_word_cleared))
+ cleared = ULONG(sbitmap_word_buf +
OFFSET(sbitmap_word_cleared));
+ else
+ cleared = 0;
word_bits = __map_depth(sc, i);
word &= ~cleared;
@@ -219,7 +226,6 @@ static void __sbitmap_for_each_set(const struct
sbitmap_context *sc,
{
const ulong sbitmap_word_size = SIZE(sbitmap_word);
const ulong w_word_off = OFFSET(sbitmap_word_word);
- const ulong w_cleared_off = OFFSET(sbitmap_word_cleared);
unsigned int index;
unsigned int nr;
@@ -245,7 +251,10 @@ static void __sbitmap_for_each_set(const struct
sbitmap_context *sc,
}
w_word = ULONG(sbitmap_word_buf + w_word_off);
- w_cleared = ULONG(sbitmap_word_buf + w_cleared_off);
+ if (VALID_MEMBER(sbitmap_word_cleared))
+ w_cleared = ULONG(sbitmap_word_buf +
OFFSET(sbitmap_word_cleared));
+ else
+ w_cleared = 0;
depth = min(__map_depth(sc, index) - nr, sc->depth - scanned);
@@ -297,7 +306,8 @@ static void sbitmap_queue_show(const struct
sbitmap_queue_context *sqc,
fprintf(fp, "depth = %u\n", sc->depth);
fprintf(fp, "busy = %u\n", sbitmap_weight(sc) - sbitmap_cleared(sc));
- fprintf(fp, "cleared = %u\n", sbitmap_cleared(sc));
+ if (VALID_MEMBER(sbitmap_word_cleared)) /* 5.0 and later */
+ fprintf(fp, "cleared = %u\n", sbitmap_cleared(sc));
fprintf(fp, "bits_per_word = %u\n", 1U << sc->shift);
fprintf(fp, "map_nr = %u\n", sc->map_nr);
--
2.27.0
--
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