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-rw-r--r--kernel/trace/trace.c57
1 files changed, 42 insertions, 15 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 9d20cd9743e..20c755e018c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -595,6 +595,28 @@ void free_snapshot(struct trace_array *tr)
}
/**
+ * tracing_alloc_snapshot - allocate snapshot buffer.
+ *
+ * This only allocates the snapshot buffer if it isn't already
+ * allocated - it doesn't also take a snapshot.
+ *
+ * This is meant to be used in cases where the snapshot buffer needs
+ * to be set up for events that can't sleep but need to be able to
+ * trigger a snapshot.
+ */
+int tracing_alloc_snapshot(void)
+{
+ struct trace_array *tr = &global_trace;
+ int ret;
+
+ ret = alloc_snapshot(tr);
+ WARN_ON(ret < 0);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
+
+/**
* trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
*
* This is similar to trace_snapshot(), but it will allocate the
@@ -607,11 +629,10 @@ void free_snapshot(struct trace_array *tr)
*/
void tracing_snapshot_alloc(void)
{
- struct trace_array *tr = &global_trace;
int ret;
- ret = alloc_snapshot(tr);
- if (WARN_ON(ret < 0))
+ ret = tracing_alloc_snapshot();
+ if (ret < 0)
return;
tracing_snapshot();
@@ -623,6 +644,12 @@ void tracing_snapshot(void)
WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
}
EXPORT_SYMBOL_GPL(tracing_snapshot);
+int tracing_alloc_snapshot(void)
+{
+ WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
+ return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
void tracing_snapshot_alloc(void)
{
/* Give warning */
@@ -3156,19 +3183,23 @@ tracing_write_stub(struct file *filp, const char __user *ubuf,
return count;
}
-static loff_t tracing_seek(struct file *file, loff_t offset, int origin)
+loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
{
+ int ret;
+
if (file->f_mode & FMODE_READ)
- return seq_lseek(file, offset, origin);
+ ret = seq_lseek(file, offset, whence);
else
- return 0;
+ file->f_pos = ret = 0;
+
+ return ret;
}
static const struct file_operations tracing_fops = {
.open = tracing_open,
.read = seq_read,
.write = tracing_write_stub,
- .llseek = tracing_seek,
+ .llseek = tracing_lseek,
.release = tracing_release,
};
@@ -4212,12 +4243,6 @@ out:
return sret;
}
-static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
- struct pipe_buffer *buf)
-{
- __free_page(buf->page);
-}
-
static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
unsigned int idx)
{
@@ -4229,7 +4254,7 @@ static const struct pipe_buf_operations tracing_pipe_buf_ops = {
.map = generic_pipe_buf_map,
.unmap = generic_pipe_buf_unmap,
.confirm = generic_pipe_buf_confirm,
- .release = tracing_pipe_buf_release,
+ .release = generic_pipe_buf_release,
.steal = generic_pipe_buf_steal,
.get = generic_pipe_buf_get,
};
@@ -4913,7 +4938,7 @@ static const struct file_operations snapshot_fops = {
.open = tracing_snapshot_open,
.read = seq_read,
.write = tracing_snapshot_write,
- .llseek = tracing_seek,
+ .llseek = tracing_lseek,
.release = tracing_snapshot_release,
};
@@ -5883,6 +5908,8 @@ allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size
rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
+ buf->tr = tr;
+
buf->buffer = ring_buffer_alloc(size, rb_flags);
if (!buf->buffer)
return -ENOMEM;