LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
* [PATCH] ptp: ocp: Avoid operator precedence warning in ptp_ocp_summary_show()
@ 2021-09-16 19:43 Nathan Chancellor
  2021-09-17  4:29 ` Jonathan Lemon
  0 siblings, 1 reply; 2+ messages in thread
From: Nathan Chancellor @ 2021-09-16 19:43 UTC (permalink / raw)
  To: Richard Cochran, Jonathan Lemon, David S. Miller, Jakub Kicinski
  Cc: netdev, linux-kernel, llvm, Nathan Chancellor

Clang warns twice:

drivers/ptp/ptp_ocp.c:2065:16: error: operator '?:' has lower precedence
than '&'; '&' will be evaluated first
[-Werror,-Wbitwise-conditional-parentheses]
                           on & map ? " ON" : "OFF", src);
                           ~~~~~~~~ ^
drivers/ptp/ptp_ocp.c:2065:16: note: place parentheses around the '&'
expression to silence this warning
                           on & map ? " ON" : "OFF", src);
                                    ^
                           (       )
drivers/ptp/ptp_ocp.c:2065:16: note: place parentheses around the '?:'
expression to evaluate it first
                           on & map ? " ON" : "OFF", src);
                                    ^

It is clearly intentional that the bitwise operation be done before the
ternary operation so add the parentheses as it suggests to fix the
warning.

Fixes: a62a56d04e63 ("ptp: ocp: Enable 4th timestamper / PPS generator")
Link: https://github.com/ClangBuiltLinux/linux/issues/1457
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 drivers/ptp/ptp_ocp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/ptp/ptp_ocp.c b/drivers/ptp/ptp_ocp.c
index 844b1401cc5d..4ba3fb254a92 100644
--- a/drivers/ptp/ptp_ocp.c
+++ b/drivers/ptp/ptp_ocp.c
@@ -2062,11 +2062,11 @@ ptp_ocp_summary_show(struct seq_file *s, void *data)
 		on = ioread32(&ts_reg->enable);
 		map = !!(bp->pps_req_map & OCP_REQ_TIMESTAMP);
 		seq_printf(s, "%7s: %s, src: %s\n", "TS3",
-			   on & map ? " ON" : "OFF", src);
+			   (on & map) ? " ON" : "OFF", src);
 
 		map = !!(bp->pps_req_map & OCP_REQ_PPS);
 		seq_printf(s, "%7s: %s, src: %s\n", "PPS",
-			   on & map ? " ON" : "OFF", src);
+			   (on & map) ? " ON" : "OFF", src);
 	}
 
 	if (bp->irig_out) {

base-commit: 4b5a3ab17c6c942bd428984b6b37fe3c07f18ab3
-- 
2.33.0


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] ptp: ocp: Avoid operator precedence warning in ptp_ocp_summary_show()
  2021-09-16 19:43 [PATCH] ptp: ocp: Avoid operator precedence warning in ptp_ocp_summary_show() Nathan Chancellor
@ 2021-09-17  4:29 ` Jonathan Lemon
  0 siblings, 0 replies; 2+ messages in thread
From: Jonathan Lemon @ 2021-09-17  4:29 UTC (permalink / raw)
  To: Nathan Chancellor
  Cc: Richard Cochran, David S. Miller, Jakub Kicinski, netdev,
	linux-kernel, llvm

On Thu, Sep 16, 2021 at 12:43:51PM -0700, Nathan Chancellor wrote:
> Clang warns twice:
> 
> drivers/ptp/ptp_ocp.c:2065:16: error: operator '?:' has lower precedence
> than '&'; '&' will be evaluated first
> [-Werror,-Wbitwise-conditional-parentheses]
>                            on & map ? " ON" : "OFF", src);
>                            ~~~~~~~~ ^
> drivers/ptp/ptp_ocp.c:2065:16: note: place parentheses around the '&'
> expression to silence this warning
>                            on & map ? " ON" : "OFF", src);
>                                     ^
>                            (       )
> drivers/ptp/ptp_ocp.c:2065:16: note: place parentheses around the '?:'
> expression to evaluate it first
>                            on & map ? " ON" : "OFF", src);
>                                     ^
> 
> It is clearly intentional that the bitwise operation be done before the
> ternary operation so add the parentheses as it suggests to fix the
> warning.

Actually, the correct fix is to change '&' to '&&', so a logical
operation is done instead of an arithmetic operation.  I believe
this will silence the warning from clang.
-- 
Jonathan

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2021-09-17  4:29 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-16 19:43 [PATCH] ptp: ocp: Avoid operator precedence warning in ptp_ocp_summary_show() Nathan Chancellor
2021-09-17  4:29 ` Jonathan Lemon

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).