Merge tag 'v4.1-rc1' into patchwork

Linux 4.1-rc1

* tag 'v4.1-rc1': (11651 commits)
  Linux 4.1-rc1
  x86_64, asm: Work around AMD SYSRET SS descriptor attribute issue
  v4l: xilinx: fix for include file movement
  platform/chrome: chromeos_laptop - instantiate Atmel at primary address
  RCU pathwalk breakage when running into a symlink overmounting something
  fix I_DIO_WAKEUP definition
  direct-io: only inc/dec inode->i_dio_count for file systems
  fs/9p: fix readdir()
  Btrfs: prevent list corruption during free space cache processing
  toshiba_acpi: Do not register vendor backlight when acpi_video bl is available
  x86: fix special __probe_kernel_write() tail zeroing case
  crypto: img-hash - CRYPTO_DEV_IMGTEC_HASH should depend on HAS_DMA
  crypto: x86/sha512_ssse3 - fixup for asm function prototype change
  nios2: rework cache
  nios2: Add types.h header required for __u32 type
  ALSA: hda - fix headset mic detection problem for one more machine
  eth: bf609 eth clock: add pclk clock for stmmac driver probe
  blackfin: Wire up missing syscalls
  Btrfs: fix inode cache writeout
  ACPI / scan: Add a scan handler for PRP0001
  ...

1 files changed, 78 insertions, 0 deletions

diff --git a/tools/lib/api/fs/tracefs.c b/tools/lib/api/fs/tracefs.c
new file mode 100644
index 000000000000..e4aa9688b71e
--- /dev/null
+++ b/tools/lib/api/fs/tracefs.c
@@ -0,0 +1,78 @@
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <sys/vfs.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mount.h>
+#include <linux/kernel.h>
+
+#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;
+
+bool tracefs_configured(void)
+{
+	return tracefs_find_mountpoint() != NULL;
+}
+
+/* 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;
+}