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* [PATCH] mm/percpu.c: Modify size of populated bitmap of chunk for memory allocation
       [not found] <dennis@kernel.org; tj@kernel.org; cl@linux.com; akpm@linux-foundation.org>
@ 2020-08-02 12:12 ` mcsmonk
  0 siblings, 0 replies; only message in thread
From: mcsmonk @ 2020-08-02 12:12 UTC (permalink / raw)
  To: linux-kernel; +Cc: Sunghyun Jin

From: Sunghyun Jin <mcsmonk@gmail.com>

Variable populated, which is a member of struct pcpu_chunk, is used as a
unit of size of unsigned long in below code:
```
1142         /* manage populated page bitmap */
1143         chunk->immutable = true;
1144         bitmap_fill(chunk->populated, chunk->nr_pages);
```

```
230 static inline void bitmap_fill(unsigned long *dst, unsigned int
nbits)
231 {
232         unsigned int len = BITS_TO_LONGS(nbits)
                               * sizeof(unsigned long);
233         memset(dst, 0xff, len);
234 }
```

However, size of populated is miscounted. So, I fix this minor
part.

Signed-off-by: Sunghyun Jin <mcsmonk@gmail.com>
---
 mm/percpu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index 696367b18222..d83e0032cb20 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1300,7 +1300,7 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr,
 
 	/* allocate chunk */
 	alloc_size = sizeof(struct pcpu_chunk) +
-		BITS_TO_LONGS(region_size >> PAGE_SHIFT);
+		BITS_TO_LONGS(region_size >> PAGE_SHIFT) * sizeof(unsigned long);
 	chunk = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
 	if (!chunk)
 		panic("%s: Failed to allocate %zu bytes\n", __func__,
-- 
2.17.1


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2020-08-02 12:12 ` [PATCH] mm/percpu.c: Modify size of populated bitmap of chunk for memory allocation mcsmonk

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