perf tools: Do parameter validation earlier on fetch_kernel_version() (44b58e06) · Commits · 戴 / test

While trying to reduce util.[ch] I noticed that fetch_kernel_version() and fetch_ubuntu_kernel_version() do lots of operations only to check if they are needed, i.e. it checks if the pointer where to return the kernel version is NULL only after obtaining the kernel version from /proc/version_signature or by parsing the results from uname(). Do it earlier not to confuse people reading this code in the future :-) Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/n/tip-i94qwyekk4tzbu0b9ce1r1mz@git.kernel.org Signed-off-by:

Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/util.c

+10 −5

Original line number	Diff line number	Diff line
		@@ -350,8 +350,12 @@ fetch_ubuntu_kernel_version(unsigned int *puint)
		size_t line_len = 0;
		char ptr, line = NULL;
		int version, patchlevel, sublevel, err;
		FILE *vsig = fopen("/proc/version_signature", "r");
		FILE *vsig;

		if (!puint)
		return 0;

		vsig = fopen("/proc/version_signature", "r");
		if (!vsig) {
		pr_debug("Open /proc/version_signature failed: %s\n",
		strerror(errno));
		@@ -381,7 +385,6 @@ fetch_ubuntu_kernel_version(unsigned int *puint)
		goto errout;
		}

		if (puint)
		*puint = (version << 16) + (patchlevel << 8) + sublevel;
		err = 0;
		errout:
		@@ -409,6 +412,9 @@ fetch_kernel_version(unsigned int puint, char str,
		str[str_size - 1] = '\0';
		}

		if (!puint \|\| int_ver_ready)
		return 0;

		err = sscanf(utsname.release, "%d.%d.%d",
		&version, &patchlevel, &sublevel);

		@@ -418,7 +424,6 @@ fetch_kernel_version(unsigned int puint, char str,
		return -1;
		}

		if (puint && !int_ver_ready)
		*puint = (version << 16) + (patchlevel << 8) + sublevel;
		return 0;
		}

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