diff mbox series

net: hns3: reduce stack usage in hclge_dbg_dump_tm_pri()

Message ID 20231204072932.1077878-1-arnd@kernel.org (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: hns3: reduce stack usage in hclge_dbg_dump_tm_pri() | expand

Checks

Context Check Description
netdev/series_format warning Single patches do not need cover letters; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1115 this patch: 1115
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 1142 this patch: 1142
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1142 this patch: 1142
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 29 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Arnd Bergmann Dec. 4, 2023, 7:29 a.m. UTC 
From: Arnd Bergmann <arnd@arndb.de>

This function exceeds the stack frame warning limit:

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c: In function 'hclge_dbg_dump_tm_pri':
drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c:1039:1: error: the frame size of 1408 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

Use dynamic allocation for the largest stack object instead. It
would be nice to rewrite this file to completely avoid the extra
buffer and just use the one that was already allocated by debugfs,
but that is a much larger change.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 .../net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c   | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Comments

Jijie Shao Dec. 4, 2023, 8:31 a.m. UTC | #1 
on 2023/12/4 15:29, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
>
> @@ -981,7 +981,7 @@ static const struct hclge_dbg_item tm_pri_items[] = {
>   
>   static int hclge_dbg_dump_tm_pri(struct hclge_dev *hdev, char *buf, int len)
>   {
> -	char data_str[ARRAY_SIZE(tm_pri_items)][HCLGE_DBG_DATA_STR_LEN];
> +	char *data_str;
>   	struct hclge_tm_shaper_para c_shaper_para, p_shaper_para;
>   	char *result[ARRAY_SIZE(tm_pri_items)], *sch_mode_str;
>   	char content[HCLGE_DBG_TM_INFO_LEN];
> @@ -991,9 +991,13 @@ static int hclge_dbg_dump_tm_pri(struct hclge_dev *hdev, char *buf, int len)
>   	ret = hclge_tm_get_pri_num(hdev, &pri_num);
>   	if (ret)
>   		return ret;

Thanks,
  But it would be better if there is an empty line here.

> +	data_str = kcalloc(ARRAY_SIZE(tm_pri_items), HCLGE_DBG_DATA_STR_LEN,
> +			   GFP_KERNEL);
> +	if (!data_str)
> +		return -ENOMEM;
>   
>   	for (i = 0; i < ARRAY_SIZE(tm_pri_items); i++)
> -		result[i] = &data_str[i][0];
> +		result[i] = &data_str[i * HCLGE_DBG_DATA_STR_LEN];
>   
>   	hclge_dbg_fill_content(content, sizeof(content), tm_pri_items,
>   			       NULL, ARRAY_SIZE(tm_pri_items));
> @@ -1035,6 +1039,7 @@ static int hclge_dbg_dump_tm_pri(struct hclge_dev *hdev, char *buf, int len)
>   		pos += scnprintf(buf + pos, len - pos, "%s", content);
>   	}
>   

all exception condition also need to free memory before return. eg:
	for (i = 0; i < pri_num; i++) {
		ret = hclge_tm_get_pri_sch_mode(hdev, i, &sch_mode);
		if (ret)
			return ret;

		ret = hclge_tm_get_pri_weight(hdev, i, &weight);
		if (ret)
			return ret;

> +	kfree(data_str);
>   	return 0;
>   }
>
Arnd Bergmann Dec. 4, 2023, 8:52 a.m. UTC | #2 
On Mon, Dec 4, 2023, at 09:31, Jijie Shao wrote:
> on 2023/12/4 15:29, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>>
>>
>> @@ -981,7 +981,7 @@ static const struct hclge_dbg_item tm_pri_items[] = {
>>   
>>   static int hclge_dbg_dump_tm_pri(struct hclge_dev *hdev, char *buf, int len)
>>   {
>> -	char data_str[ARRAY_SIZE(tm_pri_items)][HCLGE_DBG_DATA_STR_LEN];
>> +	char *data_str;
>>   	struct hclge_tm_shaper_para c_shaper_para, p_shaper_para;
>>   	char *result[ARRAY_SIZE(tm_pri_items)], *sch_mode_str;
>>   	char content[HCLGE_DBG_TM_INFO_LEN];
>> @@ -991,9 +991,13 @@ static int hclge_dbg_dump_tm_pri(struct hclge_dev *hdev, char *buf, int len)
>>   	ret = hclge_tm_get_pri_num(hdev, &pri_num);
>>   	if (ret)
>>   		return ret;
>
> Thanks,
>   But it would be better if there is an empty line here.

ok

>
> all exception condition also need to free memory before return. eg:


Indeed, I'll send a v2 in a bit.

     Arnd
diff mbox series

Patch

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c
index ff3f8f424ad9..9b5d46fdfd6c 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_debugfs.c
@@ -981,7 +981,7 @@  static const struct hclge_dbg_item tm_pri_items[] = {
 
 static int hclge_dbg_dump_tm_pri(struct hclge_dev *hdev, char *buf, int len)
 {
-	char data_str[ARRAY_SIZE(tm_pri_items)][HCLGE_DBG_DATA_STR_LEN];
+	char *data_str;
 	struct hclge_tm_shaper_para c_shaper_para, p_shaper_para;
 	char *result[ARRAY_SIZE(tm_pri_items)], *sch_mode_str;
 	char content[HCLGE_DBG_TM_INFO_LEN];
@@ -991,9 +991,13 @@  static int hclge_dbg_dump_tm_pri(struct hclge_dev *hdev, char *buf, int len)
 	ret = hclge_tm_get_pri_num(hdev, &pri_num);
 	if (ret)
 		return ret;
+	data_str = kcalloc(ARRAY_SIZE(tm_pri_items), HCLGE_DBG_DATA_STR_LEN,
+			   GFP_KERNEL);
+	if (!data_str)
+		return -ENOMEM;
 
 	for (i = 0; i < ARRAY_SIZE(tm_pri_items); i++)
-		result[i] = &data_str[i][0];
+		result[i] = &data_str[i * HCLGE_DBG_DATA_STR_LEN];
 
 	hclge_dbg_fill_content(content, sizeof(content), tm_pri_items,
 			       NULL, ARRAY_SIZE(tm_pri_items));
@@ -1035,6 +1039,7 @@  static int hclge_dbg_dump_tm_pri(struct hclge_dev *hdev, char *buf, int len)
 		pos += scnprintf(buf + pos, len - pos, "%s", content);
 	}
 
+	kfree(data_str);
 	return 0;
 }