Re: [PATCH] wifi: ray_cs: Replace the ternary conditional operator with min()

From: Simon Horman
Date: Mon Jun 26 2023 - 08:29:24 EST


On Mon, Jun 26, 2023 at 05:35:02PM +0800, You Kangren wrote:
> Replace the ternary conditional operator with min() to make the code clean
>
> Signed-off-by: You Kangren <youkangren@xxxxxxxx>
> ---
> drivers/net/wireless/legacy/ray_cs.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/net/wireless/legacy/ray_cs.c b/drivers/net/wireless/legacy/ray_cs.c
> index 8ace797ce951..96f34d90f601 100644
> --- a/drivers/net/wireless/legacy/ray_cs.c
> +++ b/drivers/net/wireless/legacy/ray_cs.c
> @@ -2086,8 +2086,7 @@ static void ray_rx(struct net_device *dev, ray_dev_t *local,
> rx_data(dev, prcs, pkt_addr, rx_len);
>
> copy_from_rx_buff(local, (UCHAR *) &local->last_bcn, pkt_addr,
> - rx_len < sizeof(struct beacon_rx) ?
> - rx_len : sizeof(struct beacon_rx));
> + min(rx_len, sizeof(struct beacon_rx));

Hi You Kangren,

I like where you are going with this patch.
But unfortunately using min() here causes an x86_64 allmodconfig W=1 build
to fail with both gcc-12 and clang-16.

Perhaps min_t() would be more appropriate?

GCC 12.3.0 says:

In file included from ./include/linux/kernel.h:27,
from ./arch/x86/include/asm/percpu.h:27,
from ./arch/x86/include/asm/nospec-branch.h:14,
from ./arch/x86/include/asm/paravirt_types.h:27,
from ./arch/x86/include/asm/ptrace.h:97,
from ./arch/x86/include/asm/math_emu.h:5,
from ./arch/x86/include/asm/processor.h:13,
from ./arch/x86/include/asm/timex.h:5,
from ./include/linux/timex.h:67,
from ./include/linux/time32.h:13,
from ./include/linux/time.h:60,
from ./include/linux/stat.h:19,
from ./include/linux/module.h:13,
from drivers/net/wireless/legacy/ray_cs.c:20:
drivers/net/wireless/legacy/ray_cs.c: In function 'ray_rx':
./include/linux/minmax.h:20:35: warning: comparison of distinct pointer types lacks a cast
20 | (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
| ^~
./include/linux/minmax.h:26:18: note: in expansion of macro '__typecheck'
26 | (__typecheck(x, y) && __no_side_effects(x, y))
| ^~~~~~~~~~~
./include/linux/minmax.h:36:31: note: in expansion of macro '__safe_cmp'
36 | __builtin_choose_expr(__safe_cmp(x, y), \
| ^~~~~~~~~~
./include/linux/minmax.h:67:25: note: in expansion of macro '__careful_cmp'
67 | #define min(x, y) __careful_cmp(x, y, <)
| ^~~~~~~~~~~~~
drivers/net/wireless/legacy/ray_cs.c:2089:35: note: in expansion of macro 'min'
2089 | min(rx_len, sizeof(struct beacon_rx));
| ^~~
drivers/net/wireless/legacy/ray_cs.c:2089:72: error: expected ')' before ';' token
2089 | min(rx_len, sizeof(struct beacon_rx));
| ^
drivers/net/wireless/legacy/ray_cs.c:2088:34: note: to match this '('
2088 | copy_from_rx_buff(local, (UCHAR *) &local->last_bcn, pkt_addr,
| ^
drivers/net/wireless/legacy/ray_cs.c:2098:23: error: expected ';' before '}' token
2098 | break;
| ^
| ;
2099 | }
| ~