From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754877AbbBRS2r (ORCPT ); Wed, 18 Feb 2015 13:28:47 -0500 Received: from terminus.zytor.com ([198.137.202.10]:40850 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753221AbbBRS2p (ORCPT ); Wed, 18 Feb 2015 13:28:45 -0500 Date: Wed, 18 Feb 2015 10:28:28 -0800 From: "tip-bot for Steven Rostedt (Red Hat)" Message-ID: Cc: rostedt@goodmis.org, masami.hiramatsu.pt@hitachi.com, akpm@linux-foundation.org, hpa@zytor.com, tglx@linutronix.de, namhyung@kernel.org, mingo@kernel.org, linux-kernel@vger.kernel.org, acme@redhat.com, jolsa@kernel.org Reply-To: rostedt@goodmis.org, masami.hiramatsu.pt@hitachi.com, akpm@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com, namhyung@kernel.org, mingo@kernel.org, linux-kernel@vger.kernel.org, acme@redhat.com, jolsa@kernel.org In-Reply-To: <20150202193552.898934751@goodmis.org> References: <20150202193552.898934751@goodmis.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] tools lib api fs: Add tracefs mount helper functions Git-Commit-ID: 4ef92c2ecd96ebad171e554020c83ce9fdb343ae X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 4ef92c2ecd96ebad171e554020c83ce9fdb343ae Gitweb: http://git.kernel.org/tip/4ef92c2ecd96ebad171e554020c83ce9fdb343ae Author: Steven Rostedt (Red Hat) AuthorDate: Mon, 2 Feb 2015 14:35:04 -0500 Committer: Arnaldo Carvalho de Melo CommitDate: Sat, 7 Feb 2015 13:55:20 +0100 tools lib api fs: Add tracefs mount helper functions Since tracefs will now hold the event directory for perf, and even though by default, debugfs still mounts tracefs on the debugfs/tracing directory, the system admin may now choose to not mount debugfs and instead just mount tracefs instead. Having tracefs helper functions will facilitate having perf look for tracefs first, and then try debugfs as a fallback. Signed-off-by: Steven Rostedt Acked-by: Jiri Olsa Cc: Andrew Morton Cc: Ingo Molnar Cc: Masami Hiramatsu Cc: Namhyung Kim Link: http://lkml.kernel.org/r/20150202193552.898934751@goodmis.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/lib/api/Makefile | 2 ++ tools/lib/api/fs/tracefs.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++ tools/lib/api/fs/tracefs.h | 20 +++++++++++++ 3 files changed, 92 insertions(+) diff --git a/tools/lib/api/Makefile b/tools/lib/api/Makefile index 22b2f15..212aa4f 100644 --- a/tools/lib/api/Makefile +++ b/tools/lib/api/Makefile @@ -9,12 +9,14 @@ LIB_H= LIB_OBJS= LIB_H += fs/debugfs.h +LIB_H += fs/tracefs.h LIB_H += fs/findfs.h LIB_H += fs/fs.h # See comment below about piggybacking... LIB_H += fd/array.h LIB_OBJS += $(OUTPUT)fs/debugfs.o +LIB_OBJS += $(OUTPUT)fs/tracefs.o LIB_OBJS += $(OUTPUT)fs/findfs.o LIB_OBJS += $(OUTPUT)fs/fs.o # XXX piggybacking here, need to introduce libapikfd, or rename this diff --git a/tools/lib/api/fs/tracefs.c b/tools/lib/api/fs/tracefs.c new file mode 100644 index 0000000..ef40d15 --- /dev/null +++ b/tools/lib/api/fs/tracefs.c @@ -0,0 +1,70 @@ +#include +#include +#include +#include +#include +#include +#include +#include + +#include "tracefs.h" + +#ifndef TRACEFS_DEFAULT_PATH +#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing" +#endif + +char tracefs_mountpoint[PATH_MAX + 1] = TRACEFS_DEFAULT_PATH; + +static const char * const tracefs_known_mountpoints[] = { + TRACEFS_DEFAULT_PATH, + "/sys/kernel/debug/tracing", + "/tracing", + "/trace", + 0, +}; + +static bool tracefs_found; + +/* find the path to the mounted tracefs */ +const char *tracefs_find_mountpoint(void) +{ + const char *ret; + + if (tracefs_found) + return (const char *)tracefs_mountpoint; + + ret = find_mountpoint("tracefs", (long) TRACEFS_MAGIC, + tracefs_mountpoint, PATH_MAX + 1, + tracefs_known_mountpoints); + + if (ret) + tracefs_found = true; + + return ret; +} + +/* mount the tracefs somewhere if it's not mounted */ +char *tracefs_mount(const char *mountpoint) +{ + /* see if it's already mounted */ + if (tracefs_find_mountpoint()) + goto out; + + /* if not mounted and no argument */ + if (mountpoint == NULL) { + /* see if environment variable set */ + mountpoint = getenv(PERF_TRACEFS_ENVIRONMENT); + /* if no environment variable, use default */ + if (mountpoint == NULL) + mountpoint = TRACEFS_DEFAULT_PATH; + } + + if (mount(NULL, mountpoint, "tracefs", 0, NULL) < 0) + return NULL; + + /* save the mountpoint */ + tracefs_found = true; + strncpy(tracefs_mountpoint, mountpoint, sizeof(tracefs_mountpoint)); +out: + return tracefs_mountpoint; +} diff --git a/tools/lib/api/fs/tracefs.h b/tools/lib/api/fs/tracefs.h new file mode 100644 index 0000000..e6f7f51 --- /dev/null +++ b/tools/lib/api/fs/tracefs.h @@ -0,0 +1,20 @@ +#ifndef __API_TRACEFS_H__ +#define __API_TRACEFS_H__ + +#include "findfs.h" + +#ifndef TRACEFS_MAGIC +#define TRACEFS_MAGIC 0x74726163 +#endif + +#ifndef PERF_TRACEFS_ENVIRONMENT +#define PERF_TRACEFS_ENVIRONMENT "PERF_TRACEFS_DIR" +#endif + +const char *tracefs_find_mountpoint(void); +int tracefs_valid_mountpoint(const char *debugfs); +char *tracefs_mount(const char *mountpoint); + +extern char tracefs_mountpoint[]; + +#endif /* __API_DEBUGFS_H__ */