* [PATCH] fs/buffer: adjust the order of might_sleep() in __getblk_gfp()
@ 2023-03-23 9:37 gouhao
2023-03-23 12:23 ` Matthew Wilcox
0 siblings, 1 reply; 3+ messages in thread
From: gouhao @ 2023-03-23 9:37 UTC (permalink / raw)
To: viro, brauner; +Cc: linux-fsdevel, linux-kernel
From: Gou Hao <gouhao@uniontech.com>
If 'bh' is found in cache, just return directly.
might_sleep() is only required on slow paths.
Signed-off-by: Gou Hao <gouhao@uniontech.com>
---
fs/buffer.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index 9e1e2add541e..e13eff504fb5 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1371,10 +1371,11 @@ __getblk_gfp(struct block_device *bdev, sector_t block,
{
struct buffer_head *bh = __find_get_block(bdev, block, size);
+ if (bh)
+ return bh;
+
might_sleep();
- if (bh == NULL)
- bh = __getblk_slow(bdev, block, size, gfp);
- return bh;
+ return __getblk_slow(bdev, block, size, gfp);
}
EXPORT_SYMBOL(__getblk_gfp);
--
2.20.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] fs/buffer: adjust the order of might_sleep() in __getblk_gfp()
2023-03-23 9:37 [PATCH] fs/buffer: adjust the order of might_sleep() in __getblk_gfp() gouhao
@ 2023-03-23 12:23 ` Matthew Wilcox
2023-03-24 1:52 ` gouhao
0 siblings, 1 reply; 3+ messages in thread
From: Matthew Wilcox @ 2023-03-23 12:23 UTC (permalink / raw)
To: gouhao; +Cc: viro, brauner, linux-fsdevel, linux-kernel
On Thu, Mar 23, 2023 at 05:37:52PM +0800, gouhao@uniontech.com wrote:
> From: Gou Hao <gouhao@uniontech.com>
>
> If 'bh' is found in cache, just return directly.
> might_sleep() is only required on slow paths.
You're missing the point. The caller can't know whether the slow or
fast path will be taken. So it must _never_ call this function if it
cannot sleep.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] fs/buffer: adjust the order of might_sleep() in __getblk_gfp()
2023-03-23 12:23 ` Matthew Wilcox
@ 2023-03-24 1:52 ` gouhao
0 siblings, 0 replies; 3+ messages in thread
From: gouhao @ 2023-03-24 1:52 UTC (permalink / raw)
To: willy; +Cc: brauner, gouhao, linux-fsdevel, linux-kernel, viro
>On Thu, Mar 23, 2023 at 05:37:52PM +0800, gouhao@uniontech.com wrote:
>> From: Gou Hao <gouhao@uniontech.com>
>>
>> If 'bh' is found in cache, just return directly.
>> might_sleep() is only required on slow paths.
>
>You're missing the point. The caller can't know whether the slow or
>fast path will be taken. So it must _never_ call this function if it
>cannot sleep.
I see. Thank you for your explanation! :)
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-03-24 1:52 UTC | newest]
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2023-03-23 9:37 [PATCH] fs/buffer: adjust the order of might_sleep() in __getblk_gfp() gouhao
2023-03-23 12:23 ` Matthew Wilcox
2023-03-24 1:52 ` gouhao
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