From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
Add the interface to call splice directly from the tracefs_cpu descriptor.
The requirement is that either the passed in file descriptor is a pipe, or
that the tcpu was created with tracefs_cpu_create_fd() and the fd used
there was a pipe.
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
include/tracefs.h | 2 +-
src/tracefs-record.c | 30 ++++++++++++++++++++++++++++++
2 files changed, 31 insertions(+), 1 deletion(-)
diff --git a/include/tracefs.h b/include/tracefs.h
index 449bfd04a395..aaa77045625e 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -608,6 +608,6 @@ int tracefs_cpu_write(struct tracefs_cpu *tcpu, int wfd, bool nonblock);
int tracefs_cpu_stop(struct tracefs_cpu *tcpu);
int tracefs_cpu_flush(struct tracefs_cpu *tcpu, void *buffer);
int tracefs_cpu_flush_write(struct tracefs_cpu *tcpu, int wfd);
-
+int tracefs_cpu_pipe(struct tracefs_cpu *tcpu, int wfd, bool nonblock);
#endif /* _TRACE_FS_H */
diff --git a/src/tracefs-record.c b/src/tracefs-record.c
index fdc470d71f1e..4a15d19d5073 100644
--- a/src/tracefs-record.c
+++ b/src/tracefs-record.c
@@ -535,3 +535,33 @@ int tracefs_cpu_write(struct tracefs_cpu *tcpu, int wfd, bool nonblock)
return tot_write;
}
+
+/**
+ * tracefs_cpu_pipe - Write the raw trace file into a pipe descriptor
+ * @tcpu: The descriptor representing the raw trace file
+ * @wfd: The write file descriptor to write the data to (must be a pipe)
+ * @nonblock: Hint to not block on the read if there's no data.
+ *
+ * This will splice directly the file descriptor of the trace_pipe_raw
+ * file to the given @wfd, which must be a pipe. This can also be used
+ * if @tcpu was created with tracefs_cpu_create_fd() where the passed
+ * in @fd there was a pipe, then @wfd does not need to be a pipe.
+ *
+ * Returns the number of bytes read or negative on error.
+ */
+int tracefs_cpu_pipe(struct tracefs_cpu *tcpu, int wfd, bool nonblock)
+{
+ int mode = SPLICE_F_MOVE;
+ int ret;
+
+ ret = wait_on_input(tcpu, nonblock);
+ if (ret <= 0)
+ return ret;
+
+ if (nonblock || tcpu->flags & TC_NONBLOCK)
+ mode |= SPLICE_F_NONBLOCK;
+
+ ret = splice(tcpu->fd, NULL, wfd, NULL,
+ tcpu->pipe_size, mode);
+ return ret;
+}
--
2.35.1
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