Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  kernel/profile.c: fix section mismatch warning
  function tracing: fix wrong pos computing when read buffer has been fulfilled
  tracing: fix mmiotrace resizing crash
  ring-buffer: no preempt for sched_clock()
  ring-buffer: buffer record on/off switch

diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 536b0ca46a038d4b9c34df6206616a432db42936..e097c2e6b6dcaa212f26bf6b08b66e4c9021cb21 100644 (file)
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -120,6 +120,9 @@ unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
 u64 ring_buffer_time_stamp(int cpu);
 void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);
 
+void tracing_on(void);
+void tracing_off(void);
+
 enum ring_buffer_flags {
        RB_FL_OVERWRITE         = 1 << 0,
 };

diff --git a/kernel/profile.c b/kernel/profile.c
index 9830a037d8db1543215f02c01918af3fd980bb10..5b7d1ac7124c97e884d25c57bbf770f9f858d26f 100644 (file)
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -544,7 +544,7 @@ static const struct file_operations proc_profile_operations = {
 };
 
 #ifdef CONFIG_SMP
-static void __init profile_nop(void *unused)
+static inline void profile_nop(void *unused)
 {
 }
 

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 4a39d24568c82ffddbcbfed2a6dcb5d2b9eb7f22..e60205722d0c6abff35b05a033fe895a606d0551 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -185,7 +185,6 @@ enum {
 };
 
 static int ftrace_filtered;
-static int tracing_on;
 
 static LIST_HEAD(ftrace_new_addrs);
 
@@ -506,13 +505,10 @@ static int __ftrace_modify_code(void *data)
 {
        int *command = data;
 
-       if (*command & FTRACE_ENABLE_CALLS) {
+       if (*command & FTRACE_ENABLE_CALLS)
                ftrace_replace_code(1);
-               tracing_on = 1;
-       } else if (*command & FTRACE_DISABLE_CALLS) {
+       else if (*command & FTRACE_DISABLE_CALLS)
                ftrace_replace_code(0);
-               tracing_on = 0;
-       }
 
        if (*command & FTRACE_UPDATE_TRACE_FUNC)
                ftrace_update_ftrace_func(ftrace_trace_function);
@@ -677,7 +673,7 @@ static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 
        cnt = num_to_init / ENTRIES_PER_PAGE;
        pr_info("ftrace: allocating %ld entries in %d pages\n",
-               num_to_init, cnt);
+               num_to_init, cnt + 1);
 
        for (i = 0; i < cnt; i++) {
                pg->next = (void *)get_zeroed_page(GFP_KERNEL);
@@ -757,13 +753,11 @@ static void *t_start(struct seq_file *m, loff_t *pos)
        void *p = NULL;
        loff_t l = -1;
 
-       if (*pos != iter->pos) {
-               for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
-                       ;
-       } else {
-               l = *pos;
-               p = t_next(m, p, &l);
-       }
+       if (*pos > iter->pos)
+               *pos = iter->pos;
+
+       l = *pos;
+       p = t_next(m, p, &l);
 
        return p;
 }
@@ -774,15 +768,21 @@ static void t_stop(struct seq_file *m, void *p)
 
 static int t_show(struct seq_file *m, void *v)
 {
+       struct ftrace_iterator *iter = m->private;
        struct dyn_ftrace *rec = v;
        char str[KSYM_SYMBOL_LEN];
+       int ret = 0;
 
        if (!rec)
                return 0;
 
        kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 
-       seq_printf(m, "%s\n", str);
+       ret = seq_printf(m, "%s\n", str);
+       if (ret < 0) {
+               iter->pos--;
+               iter->idx--;
+       }
 
        return 0;
 }
@@ -808,7 +808,7 @@ ftrace_avail_open(struct inode *inode, struct file *file)
                return -ENOMEM;
 
        iter->pg = ftrace_pages_start;
-       iter->pos = -1;
+       iter->pos = 0;
 
        ret = seq_open(file, &show_ftrace_seq_ops);
        if (!ret) {
@@ -895,7 +895,7 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 
        if (file->f_mode & FMODE_READ) {
                iter->pg = ftrace_pages_start;
-               iter->pos = -1;
+               iter->pos = 0;
                iter->flags = enable ? FTRACE_ITER_FILTER :
                        FTRACE_ITER_NOTRACE;
 

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2f76193c34894e094f6374d725fd8477c4b0af72..036456cbb4f7e1ceecf929e37ed6de581866abda 100644 (file)
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -16,14 +16,49 @@
 #include <linux/list.h>
 #include <linux/fs.h>
 
+#include "trace.h"
+
+/* Global flag to disable all recording to ring buffers */
+static int ring_buffers_off __read_mostly;
+
+/**
+ * tracing_on - enable all tracing buffers
+ *
+ * This function enables all tracing buffers that may have been
+ * disabled with tracing_off.
+ */
+void tracing_on(void)
+{
+       ring_buffers_off = 0;
+}
+
+/**
+ * tracing_off - turn off all tracing buffers
+ *
+ * This function stops all tracing buffers from recording data.
+ * It does not disable any overhead the tracers themselves may
+ * be causing. This function simply causes all recording to
+ * the ring buffers to fail.
+ */
+void tracing_off(void)
+{
+       ring_buffers_off = 1;
+}
+
 /* Up this if you want to test the TIME_EXTENTS and normalization */
 #define DEBUG_SHIFT 0
 
 /* FIXME!!! */
 u64 ring_buffer_time_stamp(int cpu)
 {
+       u64 time;
+
+       preempt_disable_notrace();
        /* shift to debug/test normalization and TIME_EXTENTS */
-       return sched_clock() << DEBUG_SHIFT;
+       time = sched_clock() << DEBUG_SHIFT;
+       preempt_enable_notrace();
+
+       return time;
 }
 
 void ring_buffer_normalize_time_stamp(int cpu, u64 *ts)
@@ -503,6 +538,12 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
        LIST_HEAD(pages);
        int i, cpu;
 
+       /*
+        * Always succeed at resizing a non-existent buffer:
+        */
+       if (!buffer)
+               return size;
+
        size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
        size *= BUF_PAGE_SIZE;
        buffer_size = buffer->pages * BUF_PAGE_SIZE;
@@ -1133,6 +1174,9 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer,
        struct ring_buffer_event *event;
        int cpu, resched;
 
+       if (ring_buffers_off)
+               return NULL;
+
        if (atomic_read(&buffer->record_disabled))
                return NULL;
 
@@ -1249,6 +1293,9 @@ int ring_buffer_write(struct ring_buffer *buffer,
        int ret = -EBUSY;
        int cpu, resched;
 
+       if (ring_buffers_off)
+               return -EBUSY;
+
        if (atomic_read(&buffer->record_disabled))
                return -EBUSY;
 
@@ -2070,3 +2117,69 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
        return 0;
 }
 
+static ssize_t
+rb_simple_read(struct file *filp, char __user *ubuf,
+              size_t cnt, loff_t *ppos)
+{
+       int *p = filp->private_data;
+       char buf[64];
+       int r;
+
+       /* !ring_buffers_off == tracing_on */
+       r = sprintf(buf, "%d\n", !*p);
+
+       return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+rb_simple_write(struct file *filp, const char __user *ubuf,
+               size_t cnt, loff_t *ppos)
+{
+       int *p = filp->private_data;
+       char buf[64];
+       long val;
+       int ret;
+
+       if (cnt >= sizeof(buf))
+               return -EINVAL;
+
+       if (copy_from_user(&buf, ubuf, cnt))
+               return -EFAULT;
+
+       buf[cnt] = 0;
+
+       ret = strict_strtoul(buf, 10, &val);
+       if (ret < 0)
+               return ret;
+
+       /* !ring_buffers_off == tracing_on */
+       *p = !val;
+
+       (*ppos)++;
+
+       return cnt;
+}
+
+static struct file_operations rb_simple_fops = {
+       .open           = tracing_open_generic,
+       .read           = rb_simple_read,
+       .write          = rb_simple_write,
+};
+
+
+static __init int rb_init_debugfs(void)
+{
+       struct dentry *d_tracer;
+       struct dentry *entry;
+
+       d_tracer = tracing_init_dentry();
+
+       entry = debugfs_create_file("tracing_on", 0644, d_tracer,
+                                   &ring_buffers_off, &rb_simple_fops);
+       if (!entry)
+               pr_warning("Could not create debugfs 'tracing_on' entry\n");
+
+       return 0;
+}
+
+fs_initcall(rb_init_debugfs);