2024-04-08 21:52:45

by Sandeep Dhavale

Subject: [PATCH v1] erofs: use raw_smp_processor_id() to get buffer from global buffer pool

erofs will decompress in the preemptible context (kworker or per cpu
thread). As smp_processor_id() cannot be used in preemptible contexts,
use raw_smp_processor_id() instead to index into global buffer pool.

Reported-by: [email protected]
Fixes: 7a7513292cc6 ("erofs: rename per-CPU buffers to global buffer pool and make it configurable")
Signed-off-by: Sandeep Dhavale <[email protected]>
---
fs/erofs/zutil.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/erofs/zutil.c b/fs/erofs/zutil.c
index b9b99158bb4e..036024bce9f7 100644
--- a/fs/erofs/zutil.c
+++ b/fs/erofs/zutil.c
@@ -30,7 +30,7 @@ static struct shrinker *erofs_shrinker_info;

static unsigned int z_erofs_gbuf_id(void)
{
- return smp_processor_id() % z_erofs_gbuf_count;
+ return raw_smp_processor_id() % z_erofs_gbuf_count;
}

void *z_erofs_get_gbuf(unsigned int requiredpages)
--
2.44.0.478.gd926399ef9-goog

2024-04-08 22:48:55

by Gao Xiang

Subject: Re: [PATCH v1] erofs: use raw_smp_processor_id() to get buffer from global buffer pool

Hi Sandeep,

On 2024/4/9 05:52, Sandeep Dhavale wrote:
> erofs will decompress in the preemptible context (kworker or per cpu
> thread). As smp_processor_id() cannot be used in preemptible contexts,
> use raw_smp_processor_id() instead to index into global buffer pool.
>
> Reported-by: [email protected]
> Fixes: 7a7513292cc6 ("erofs: rename per-CPU buffers to global buffer pool and make it configurable")
> Signed-off-by: Sandeep Dhavale <[email protected]>

Thanks for catching this, since the original patch is
for next upstream cycle, may I fold this fix in the
original patch?

I will add your credit into the original patch.

Thanks,
Gao Xiang

> ---
> fs/erofs/zutil.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/erofs/zutil.c b/fs/erofs/zutil.c
> index b9b99158bb4e..036024bce9f7 100644
> --- a/fs/erofs/zutil.c
> +++ b/fs/erofs/zutil.c
> @@ -30,7 +30,7 @@ static struct shrinker *erofs_shrinker_info;
>
> static unsigned int z_erofs_gbuf_id(void)
> {
> - return smp_processor_id() % z_erofs_gbuf_count;
> + return raw_smp_processor_id() % z_erofs_gbuf_count;
> }
>
> void *z_erofs_get_gbuf(unsigned int requiredpages)

2024-04-08 23:06:08

by Sandeep Dhavale

Subject: Re: [PATCH v1] erofs: use raw_smp_processor_id() to get buffer from global buffer pool

>
> Thanks for catching this, since the original patch is
> for next upstream cycle, may I fold this fix in the
> original patch?
>
Hi Gao,
Sounds good. As the fix is simple, it makes sense to fold it into the
original one.

Thanks,
Sandeep.

2024-04-08 23:21:00

by Gao Xiang

Subject: Re: [PATCH v1] erofs: use raw_smp_processor_id() to get buffer from global buffer pool

On 2024/4/9 07:05, Sandeep Dhavale wrote:
>>
>> Thanks for catching this, since the original patch is
>> for next upstream cycle, may I fold this fix in the
>> original patch?
>>
> Hi Gao,
> Sounds good. As the fix is simple, it makes sense to fold it into the
> original one.
>
> Thanks,
> Sandeep.

Thanks, folded.

Thanks,
Gao Xiang