[PATCH v3] infiniband/hw/ocrdma: make function ocrdma_add_stat as noinline_for_stack

[PATCH v3] infiniband/hw/ocrdma: make function ocrdma_add_stat as noinline_for_stack

[flyingpenghao]

From: Peng Hao <flyingpeng@tencent.com>

clang report:
drivers/infiniband/hw/ocrdma/ocrdma_stats.c:686:16: error: stack frame size (20664) exceeds limit (2048) in 'ocrdma_dbgfs_ops_read' [-Werror,-Wframe-larger-than]
static ssize_t ocrdma_dbgfs_ops_read(struct file *filp, char __user *buffer,
               ^

A 128-byte array is defined in ocrdma_add_stat and is called multiple times
by multiple functions (up to dozens of times), which results in a large amount
of stack space being accumulated in ocrdma_dbgfs_ops_read. mark it as noinline_for_stack
to prevent it from spreading to ocrdma_dbgfs_ops_read's stack size.

Signed-off-by: Peng Hao <flyingpeng@tencent.com>
---
 drivers/infiniband/hw/ocrdma/ocrdma_stats.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/ocrdma/ocrdma_stats.c b/drivers/infiniband/hw/ocrdma/ocrdma_stats.c
index 5f831e3bdbad..0b26c4e6de53 100644
--- a/drivers/infiniband/hw/ocrdma/ocrdma_stats.c
+++ b/drivers/infiniband/hw/ocrdma/ocrdma_stats.c
@@ -46,7 +46,7 @@
 
 static struct dentry *ocrdma_dbgfs_dir;
 
-static int ocrdma_add_stat(char *start, char *pcur,
+static noinline_for_stack int ocrdma_add_stat(char *start, char *pcur,
 				char *name, u64 count)
 {
 	char buff[128] = {0};
-- 
2.27.0

Re: [PATCH v3] infiniband/hw/ocrdma: make function ocrdma_add_stat as noinline_for_stack

[Leon Romanovsky]

On Thu, Jul 11, 2024 at 04:56:47PM +0800, flyingpenghao@gmail.com wrote:
> From: Peng Hao <flyingpeng@tencent.com>
> 
> clang report:
> drivers/infiniband/hw/ocrdma/ocrdma_stats.c:686:16: error: stack frame size (20664) exceeds limit (2048) in 'ocrdma_dbgfs_ops_read' [-Werror,-Wframe-larger-than]
> static ssize_t ocrdma_dbgfs_ops_read(struct file *filp, char __user *buffer,
>                ^
> 
> A 128-byte array is defined in ocrdma_add_stat and is called multiple times
> by multiple functions (up to dozens of times), which results in a large amount
> of stack space being accumulated in ocrdma_dbgfs_ops_read. mark it as noinline_for_stack
> to prevent it from spreading to ocrdma_dbgfs_ops_read's stack size.
> 
> Signed-off-by: Peng Hao <flyingpeng@tencent.com>
> ---
>  drivers/infiniband/hw/ocrdma/ocrdma_stats.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

I merged this patch with https://lore.kernel.org/r/20240710091657.26291-1-flyingpeng@tencent.com

Thanks

> 
> diff --git a/drivers/infiniband/hw/ocrdma/ocrdma_stats.c b/drivers/infiniband/hw/ocrdma/ocrdma_stats.c
> index 5f831e3bdbad..0b26c4e6de53 100644
> --- a/drivers/infiniband/hw/ocrdma/ocrdma_stats.c
> +++ b/drivers/infiniband/hw/ocrdma/ocrdma_stats.c
> @@ -46,7 +46,7 @@
>  
>  static struct dentry *ocrdma_dbgfs_dir;
>  
> -static int ocrdma_add_stat(char *start, char *pcur,
> +static noinline_for_stack int ocrdma_add_stat(char *start, char *pcur,
>  				char *name, u64 count)
>  {
>  	char buff[128] = {0};
> -- 
> 2.27.0
> 
>