Re: I need help with a sparse warning

From: Larry Finger
Date: Thu Sep 11 2008 - 22:58:41 EST

Steven Noonan wrote:
On Thu, Sep 11, 2008 at 7:13 PM, Larry Finger <Larry.Finger@xxxxxxxxxxxx> wrote:
In file drivers/net/wireless/p54/p54common.c, the statement

priv->rx_mtu = (size_t) le16_to_cpu((__le16)bootrec->data[10]);

generates the sparse warning

.../p54common.c:185:29: warning: cast to restricted __le16

where bootrec->data is u32, and priv->rx_mtu is u16.

(Whoops, didn't CC the mailing lists. Sorry about the double-message, Larry.)

If priv->rx_mtu is u16, I'm surprised it doesn't get noisy about the
size_t cast. Unless the machine it's being compiled on is 16-bit, that
should throw a truncation warning, because size_t should be a 32-bit
integer on 32-bit machines (typically).

I think if you change the (__le16) cast to (__le16 __force) it will
stop warning you about that particular issue.

This one gets rid of the sparse warning.

priv->rx_mtu = le16_to_cpu((__le16 __force)


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