diff mbox series

[net-next,6/7] drivers: net: smc911x: Fix cast from pointer to integer of different size

Message ID 20201031004958.1059797-7-andrew@lunn.ch
State Superseded
Headers show
Series smsc W=1 warning fixes | expand

Commit Message

Andrew Lunn Oct. 31, 2020, 12:49 a.m. UTC
drivers/net/ethernet/smsc/smc911x.c: In function ‘smc911x_hardware_send_pkt’:
drivers/net/ethernet/smsc/smc911x.c:471:11: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
  471 |  cmdA = (((u32)skb->data & 0x3) << 16) |

When built on 64bit targets, the skb->data pointer cannot be cast to a
u32 in a meaningful way. Use long instead.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/ethernet/smsc/smc911x.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Jakub Kicinski Nov. 2, 2020, 11:47 p.m. UTC | #1
On Sat, 31 Oct 2020 01:49:57 +0100 Andrew Lunn wrote:
> drivers/net/ethernet/smsc/smc911x.c: In function ‘smc911x_hardware_send_pkt’:

> drivers/net/ethernet/smsc/smc911x.c:471:11: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]

>   471 |  cmdA = (((u32)skb->data & 0x3) << 16) |

> 

> When built on 64bit targets, the skb->data pointer cannot be cast to a

> u32 in a meaningful way. Use long instead.

> 

> Signed-off-by: Andrew Lunn <andrew@lunn.ch>

> ---

>  drivers/net/ethernet/smsc/smc911x.c | 6 +++---

>  1 file changed, 3 insertions(+), 3 deletions(-)

> 

> diff --git a/drivers/net/ethernet/smsc/smc911x.c b/drivers/net/ethernet/smsc/smc911x.c

> index 4ec292563f38..f37832540364 100644

> --- a/drivers/net/ethernet/smsc/smc911x.c

> +++ b/drivers/net/ethernet/smsc/smc911x.c

> @@ -466,9 +466,9 @@ static void smc911x_hardware_send_pkt(struct net_device *dev)

>  			TX_CMD_A_INT_FIRST_SEG_ | TX_CMD_A_INT_LAST_SEG_ |

>  			skb->len;

>  #else

> -	buf = (char*)((u32)skb->data & ~0x3);

> -	len = (skb->len + 3 + ((u32)skb->data & 3)) & ~0x3;

> -	cmdA = (((u32)skb->data & 0x3) << 16) |

> +	buf = (char *)((long)skb->data & ~0x3);

> +	len = (skb->len + 3 + ((long)skb->data & 3)) & ~0x3;

> +	cmdA = (((long)skb->data & 0x3) << 16) |


Probably best if you swap the (long) for something unsigned here as
well.
David Laight Nov. 3, 2020, 10:16 a.m. UTC | #2
From: Jakub Kicinski

> Sent: 02 November 2020 23:48

> 

> On Sat, 31 Oct 2020 01:49:57 +0100 Andrew Lunn wrote:

> > drivers/net/ethernet/smsc/smc911x.c: In function ‘smc911x_hardware_send_pkt’:

> > drivers/net/ethernet/smsc/smc911x.c:471:11: warning: cast from pointer to integer of different size

> [-Wpointer-to-int-cast]

> >   471 |  cmdA = (((u32)skb->data & 0x3) << 16) |

> >

> > When built on 64bit targets, the skb->data pointer cannot be cast to a

> > u32 in a meaningful way. Use long instead.

> >

> > Signed-off-by: Andrew Lunn <andrew@lunn.ch>

> > ---

> >  drivers/net/ethernet/smsc/smc911x.c | 6 +++---

> >  1 file changed, 3 insertions(+), 3 deletions(-)

> >

> > diff --git a/drivers/net/ethernet/smsc/smc911x.c b/drivers/net/ethernet/smsc/smc911x.c

> > index 4ec292563f38..f37832540364 100644

> > --- a/drivers/net/ethernet/smsc/smc911x.c

> > +++ b/drivers/net/ethernet/smsc/smc911x.c

> > @@ -466,9 +466,9 @@ static void smc911x_hardware_send_pkt(struct net_device *dev)

> >  			TX_CMD_A_INT_FIRST_SEG_ | TX_CMD_A_INT_LAST_SEG_ |

> >  			skb->len;

> >  #else

> > -	buf = (char*)((u32)skb->data & ~0x3);

> > -	len = (skb->len + 3 + ((u32)skb->data & 3)) & ~0x3;

> > -	cmdA = (((u32)skb->data & 0x3) << 16) |

> > +	buf = (char *)((long)skb->data & ~0x3);

> > +	len = (skb->len + 3 + ((long)skb->data & 3)) & ~0x3;

> > +	cmdA = (((long)skb->data & 0x3) << 16) |

> 

> Probably best if you swap the (long) for something unsigned here as

> well.


It would be much clearer with a temporary variable:
	offset = (unsigned long)skb->data & 3;
	buf = skb->data - offset;
	len = skb->len + offset;
	cmdA = offset << 16 | ...

   David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/smsc/smc911x.c b/drivers/net/ethernet/smsc/smc911x.c
index 4ec292563f38..f37832540364 100644
--- a/drivers/net/ethernet/smsc/smc911x.c
+++ b/drivers/net/ethernet/smsc/smc911x.c
@@ -466,9 +466,9 @@  static void smc911x_hardware_send_pkt(struct net_device *dev)
 			TX_CMD_A_INT_FIRST_SEG_ | TX_CMD_A_INT_LAST_SEG_ |
 			skb->len;
 #else
-	buf = (char*)((u32)skb->data & ~0x3);
-	len = (skb->len + 3 + ((u32)skb->data & 3)) & ~0x3;
-	cmdA = (((u32)skb->data & 0x3) << 16) |
+	buf = (char *)((long)skb->data & ~0x3);
+	len = (skb->len + 3 + ((long)skb->data & 3)) & ~0x3;
+	cmdA = (((long)skb->data & 0x3) << 16) |
 			TX_CMD_A_INT_FIRST_SEG_ | TX_CMD_A_INT_LAST_SEG_ |
 			skb->len;
 #endif