2020-10-30 21:01:29

by Dennis Zhou

Subject: [PATCH] percpu: convert flexible array initializers to use struct_size()

Use the safer macro as sparked by the long discussion in [1].

[1] https://lore.kernel.org/lkml/[email protected]/

Signed-off-by: Dennis Zhou <[email protected]>
---
I'll apply it to for-5.10-fixes.

mm/percpu.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index 66a93f096394..ad7a37ee74ef 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1315,8 +1315,8 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr,
region_size = ALIGN(start_offset + map_size, lcm_align);

/* allocate chunk */
- alloc_size = sizeof(struct pcpu_chunk) +
- BITS_TO_LONGS(region_size >> PAGE_SHIFT) * sizeof(unsigned long);
+ alloc_size = struct_size(chunk, populated,
+ BITS_TO_LONGS(region_size >> PAGE_SHIFT));
chunk = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
if (!chunk)
panic("%s: Failed to allocate %zu bytes\n", __func__,
@@ -2521,8 +2521,8 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
pcpu_atom_size = ai->atom_size;
- pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
- BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
+ pcpu_chunk_struct_size = struct_size(chunk, populated,
+ BITS_TO_LONGS(pcpu_unit_pages));

pcpu_stats_save_ai(ai);

--
2.29.1.341.ge80a0c044ae-goog

2020-10-30 23:06:26

by Gustavo A. R. Silva

Subject: Re: [PATCH] percpu: convert flexible array initializers to use struct_size()

On 10/30/20 15:58, Dennis Zhou wrote:
> Use the safer macro as sparked by the long discussion in [1].
>
> [1] https://lore.kernel.org/lkml/[email protected]/
>
> Signed-off-by: Dennis Zhou <[email protected]>

Reviewed-by: Gustavo A. R. Silva <[email protected]>

Thanks
--
Gustavo

> ---
> I'll apply it to for-5.10-fixes.
>
> mm/percpu.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/mm/percpu.c b/mm/percpu.c
> index 66a93f096394..ad7a37ee74ef 100644
> --- a/mm/percpu.c
> +++ b/mm/percpu.c
> @@ -1315,8 +1315,8 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr,
> region_size = ALIGN(start_offset + map_size, lcm_align);
>
> /* allocate chunk */
> - alloc_size = sizeof(struct pcpu_chunk) +
> - BITS_TO_LONGS(region_size >> PAGE_SHIFT) * sizeof(unsigned long);
> + alloc_size = struct_size(chunk, populated,
> + BITS_TO_LONGS(region_size >> PAGE_SHIFT));
> chunk = memblock_alloc(alloc_size, SMP_CACHE_BYTES);
> if (!chunk)
> panic("%s: Failed to allocate %zu bytes\n", __func__,
> @@ -2521,8 +2521,8 @@ void __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
> pcpu_unit_pages = ai->unit_size >> PAGE_SHIFT;
> pcpu_unit_size = pcpu_unit_pages << PAGE_SHIFT;
> pcpu_atom_size = ai->atom_size;
> - pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
> - BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long);
> + pcpu_chunk_struct_size = struct_size(chunk, populated,
> + BITS_TO_LONGS(pcpu_unit_pages));
>
> pcpu_stats_save_ai(ai);
>
>