From: Steven Rostedt <rostedt@goodmis.org>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@kernel.org>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 2/2] tracing: Use switch statement instead of ifs in set_tracer_flag()
Date: Mon, 10 Nov 2025 11:42:01 -0500 [thread overview]
Message-ID: <20251110114201.37d63a73@gandalf.local.home> (raw)
In-Reply-To: <20251110144826.8d92d83af67efebac2a3ecf5@kernel.org>
On Mon, 10 Nov 2025 14:48:26 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
> BTW, set_tracer_flag() seems to expect to modify only one bit.
> If we can count the number of its in @mask and reject if it is
> not 1, we can use bit-mask instead of the first switch()?
>
> if (!mask || /* mask has no bit */
> (mask & ~(1 << (ffs64(mask) - 1)))) /* mask has more than 2 bits */
> return -EINVAL;
Well, this has been around for over a decade without any issues. I don't
think a check would be of much use. Not to mention, invalid masks are OK to
pass in.
If anything, I would have liked to pass in the bit number and not a mask.
But that's something we could do another time.
-- Steve
prev parent reply other threads:[~2025-11-10 16:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-06 0:33 [PATCH 0/2] tracing: Clean up of set_tracer_flag() Steven Rostedt
2025-11-06 0:33 ` [PATCH 1/2] tracing: Exit out immediately after update_marker_trace() Steven Rostedt
2025-11-10 5:24 ` Masami Hiramatsu
2025-11-06 0:33 ` [PATCH 2/2] tracing: Use switch statement instead of ifs in set_tracer_flag() Steven Rostedt
2025-11-10 5:48 ` Masami Hiramatsu
2025-11-10 16:42 ` Steven Rostedt [this message]
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