On Thu, 10 Nov 2011, Felipe Balbi wrote:
> On Thu, Nov 10, 2011 at 10:47:12AM +0200, Felipe Balbi wrote:
> > Fix the following compile warning:
> >
> > | In file included from drivers/usb/host/ohci-hcd.c:101:0:
> > | drivers/usb/host/ohci-dbg.c: In function �@^Xfill_registers_buffer�@^Y:
> > | drivers/usb/host/ohci-dbg.c:642:2: warning: the comparison will \
> > | always evaluate as �@^Xtrue�@^Y for the address of �@^Xnext�@^Y wil$
> > | never be NULL [-Waddress]
> > | drivers/usb/host/ohci-dbg.c:661:3: warning: the comparison will \
> > | always evaluate as �@^Xtrue�@^Y for the address of �@^Xnext�@^Y wil$
> > | never be NULL [-Waddress]
I don't know; this seems like a bogus warning. In machine-generated
code (such as the output from a macro), there can easily be expressions
of the form "&x != NULL" which will always evaluate as true.
> > #define ohci_dbg_sw(ohci, next, size, format, arg...) \
> > do { \
> > - if (next != NULL) { \
> > unsigned s_len; \
> > s_len = scnprintf (*next, *size, format, ## arg ); \
> > *size -= s_len; *next += s_len; \
> > - } else \
> > - ohci_dbg(ohci,format, ## arg ); \
> > } while (0);
Nope. There can be situations where next _is_ NULL. For example, see
ohci_dump() -> ohci_dump_roothub() later on.
> I didn't look very deep, but another solution would be the one below:
>
> diff --git a/drivers/usb/host/ohci-dbg.c b/drivers/usb/host/ohci-dbg.c
> index d7d3449..5433010 100644
> --- a/drivers/usb/host/ohci-dbg.c
> +++ b/drivers/usb/host/ohci-dbg.c
> @@ -639,7 +639,7 @@ static ssize_t fill_registers_buffer(struct debug_buffer *buf)
>
> /* dump driver info, then registers in spec order */
>
> - ohci_dbg_sw (ohci, &next, &size,
> + ohci_dbg_sw (ohci, next, &size,
That's definitely wrong. The type of the second argument must be
(char **).
The proper fix is probably to make ohci_dbg_sw an inline routine
instead of a macro.
Alan Stern
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