2015-05-18 14:17:34

by Jagan Teki

[permalink] [raw]
Subject: [PATCH v2] staging: rtl8712: Use ether_addr_copy() instead of memcpy()

Fixes Warning encounter this by applying checkpatch.pl against this file:
Prefer ether_addr_copy() over memcpy() if the Ethernet addresses
are __aligned(2)

pahole output for respective structures:
- addr->sa_data
struct sockaddr {
sa_family_t sa_family; /* 0 2 */
char sa_data[14]; /* 2 14 */

/* size: 16, cachelines: 1, members: 2 */
/* last cacheline: 16 bytes */
};

- padapter->eeprompriv.mac_addr
struct _adapter {
struct dvobj_priv dvobjpriv; /* 0 40 */
struct mlme_priv mlmepriv; /* 40 1560 */
/* --- cacheline 25 boundary (1600 bytes) --- */
struct cmd_priv cmdpriv; /* 1600 136 */
/* --- cacheline 27 boundary (1728 bytes) was 8 bytes ago --- */
struct evt_priv evtpriv; /* 1736 96 */
/* --- cacheline 28 boundary (1792 bytes) was 40 bytes ago --- */
struct io_queue * pio_queue; /* 1832 8 */
struct xmit_priv xmitpriv; /* 1840 912 */
/* --- cacheline 43 boundary (2752 bytes) --- */
struct recv_priv recvpriv; /* 2752 1088 */
/* --- cacheline 60 boundary (3840 bytes) --- */
struct sta_priv stapriv; /* 3840 672 */
/* --- cacheline 70 boundary (4480 bytes) was 32 bytes ago --- */
struct security_priv securitypriv; /* 4512 4816 */
/* --- cacheline 145 boundary (9280 bytes) was 48 bytes ago --- */
struct registry_priv registrypriv; /* 9328 968 */
/* --- cacheline 160 boundary (10240 bytes) was 56 bytes ago --- */
struct wlan_acl_pool acl_list; /* 10296 1536 */
/* --- cacheline 184 boundary (11776 bytes) was 56 bytes ago --- */
struct pwrctrl_priv pwrctrlpriv; /* 11832 224 */
/* --- cacheline 188 boundary (12032 bytes) was 24 bytes ago --- */
struct eeprom_priv eeprompriv; /* 12056 508 */
........
};

struct eeprom_priv {
u8 bautoload_fail_flag; /* 0 1 */
u8 bempty; /* 1 1 */
u8 sys_config; /* 2 1 */
u8 mac_addr[6]; /* 3 6 */
......
};

- pnetdev->dev_addr
dev_addr is interface address infor from generic net_device structure
which is properly aligned and have some patches with this change as well.
"staging: rtl8712: fix Prefer ether_addr_copy() over memcpy()"
(sha1: 36e4d8826b317080e283e4edd08bf8d5ac706f38)

Signed-off-by: Jagan Teki <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Larry Finger <[email protected]>
Cc: Florian Schilhabel <[email protected]>
---
Changes for v2:
- Describe a changelog, to prove address are aligned.

drivers/staging/rtl8712/os_intfs.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/rtl8712/os_intfs.c b/drivers/staging/rtl8712/os_intfs.c
index 6e776e5..0d27df6 100644
--- a/drivers/staging/rtl8712/os_intfs.c
+++ b/drivers/staging/rtl8712/os_intfs.c
@@ -181,7 +181,7 @@ static int r871x_net_set_mac_address(struct net_device *pnetdev, void *p)
struct sockaddr *addr = p;

if (padapter->bup == false)
- memcpy(pnetdev->dev_addr, addr->sa_data, ETH_ALEN);
+ ether_addr_copy(pnetdev->dev_addr, addr->sa_data);
return 0;
}

@@ -395,8 +395,8 @@ static int netdev_open(struct net_device *pnetdev)
goto netdev_open_error;
if (r8712_initmac == NULL)
/* Use the mac address stored in the Efuse */
- memcpy(pnetdev->dev_addr,
- padapter->eeprompriv.mac_addr, ETH_ALEN);
+ ether_addr_copy(pnetdev->dev_addr,
+ padapter->eeprompriv.mac_addr);
else {
/* We have to inform f/w to use user-supplied MAC
* address.
@@ -412,8 +412,8 @@ static int netdev_open(struct net_device *pnetdev)
* the eeprompriv.mac_addr should store the mac which
* users specify.
*/
- memcpy(padapter->eeprompriv.mac_addr,
- pnetdev->dev_addr, ETH_ALEN);
+ ether_addr_copy(padapter->eeprompriv.mac_addr,
+ pnetdev->dev_addr);
}
if (start_drv_threads(padapter) != _SUCCESS)
goto netdev_open_error;
--
1.9.1


2015-05-18 14:39:14

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH v2] staging: rtl8712: Use ether_addr_copy() instead of memcpy()

On Mon, May 18, 2015 at 07:47:06PM +0530, Jagan Teki wrote:
> struct eeprom_priv {
> u8 bautoload_fail_flag; /* 0 1 */
> u8 bempty; /* 1 1 */
> u8 sys_config; /* 2 1 */
> u8 mac_addr[6]; /* 3 6 */
> ......
> };

This means it's not aligned as we want.

regards,
dan carpenter

2015-05-18 16:04:41

by Jagan Teki

[permalink] [raw]
Subject: Re: [PATCH v2] staging: rtl8712: Use ether_addr_copy() instead of memcpy()

On 18 May 2015 at 20:08, Dan Carpenter <[email protected]> wrote:
> On Mon, May 18, 2015 at 07:47:06PM +0530, Jagan Teki wrote:
>> struct eeprom_priv {
>> u8 bautoload_fail_flag; /* 0 1 */
>> u8 bempty; /* 1 1 */
>> u8 sys_config; /* 2 1 */
>> u8 mac_addr[6]; /* 3 6 */
>> ......
>> };
>
> This means it's not aligned as we want.

Why size upto mac_addr is 9 and is not divisible by 2 is it?

or the mac_addr size is 6 which is divisible by 2 (__align(2))

this is full pahole:

struct eeprom_priv {
u8 bautoload_fail_flag; /* 0 1 */
u8 bempty; /* 1 1 */
u8 sys_config; /* 2 1 */
u8 mac_addr[6]; /* 3 6 */
u8 config0; /* 9 1 */
u16 channel_plan; /* 10 2 */
u8 country_string[3]; /* 12 3 */
u8 tx_power_b[15]; /* 15 15 */
u8 tx_power_g[15]; /* 30 15 */
u8 tx_power_a[201]; /* 45 201 */
/* --- cacheline 3 boundary (192 bytes) was 54 bytes ago --- */
u8 efuse_eeprom_data[256]; /* 246 256 */

/* XXX 2 bytes hole, try to pack */

/* --- cacheline 7 boundary (448 bytes) was 56 bytes ago --- */
enum RT_CUSTOMER_ID CustomerID; /* 504 4 */

/* size: 508, cachelines: 8, members: 12 */
/* sum members: 506, holes: 1, sum holes: 2 */
/* last cacheline: 60 bytes */
};

thanks!
--
Jagan Teki,
Openedev.

2015-05-18 16:09:31

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH v2] staging: rtl8712: Use ether_addr_copy() instead of memcpy()


#include <stdio.h>

struct foo {
unsigned char one;
unsigned char two;
unsigned char three;
unsigned char mac_addr[6];
unsigned short channel_plan;
};

int main(void)
{
struct foo *p = NULL;

printf("%x\n", &p->mac_addr);

return 0;
}

This program does not print an even number so the alignment is off.

regards,
dan carpenter