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Date:   Tue, 23 Jun 2020 16:56:01 +0200
From:   Jiri Olsa <jolsa@redhat.com>
To:     Alexey Budankov <alexey.budankov@linux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Andi Kleen <ak@linux.intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v8 03/13] perf evlist: implement control command handling
 functions
Message-ID: <20200623145601.GH2619137@krava>
References: <0781a077-aa82-5b4a-273e-c17372a72b93@linux.intel.com>
 <d47ef616-e2cf-9131-159f-5be1a31438a7@linux.intel.com>
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On Wed, Jun 17, 2020 at 11:36:46AM +0300, Alexey Budankov wrote:

SNIP

> +	memset(cmd_data, 0, data_size--);
> +
> +	do {
> +		err = read(evlist->ctl_fd.fd, &c, 1);
> +		if (err > 0) {
> +			if (c == '\n' || c == '\0')
> +				break;
> +			cmd_data[bytes_read++] = c;
> +			if (bytes_read == data_size)
> +				break;
> +		} else {
> +			if (err == -1)
> +				pr_err("Failed to read from ctlfd %d: %m\n", evlist->ctl_fd.fd);
> +			break;
> +		}
> +	} while (1);
> +
> +	pr_debug("Message from ctl_fd: \"%s%s\"\n", cmd_data,
> +		 bytes_read == data_size ? "" : c == '\n' ? "\\n" : "\\0");
> +
> +	if (err > 0) {
> +		if (!strncmp(cmd_data, EVLIST_CTL_CMD_ENABLE_TAG,
> +			     strlen(EVLIST_CTL_CMD_ENABLE_TAG))) {

you could use sizeof(EVLIST_CTL_CMD_ENABLE_TAG) instead, no function call

> +			*cmd = EVLIST_CTL_CMD_ENABLE;
> +		} else if (!strncmp(cmd_data, EVLIST_CTL_CMD_DISABLE_TAG,
> +				    strlen(EVLIST_CTL_CMD_DISABLE_TAG))) {

ditto

jirka