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Subject[tip:tracing/core] tracing: update file->f_pos when splice(2) it
Commit-ID:  c7625a555f55d7ae49236cde551786c88f5a5ce1
Gitweb: http://git.kernel.org/tip/c7625a555f55d7ae49236cde551786c88f5a5ce1
Author: Lai Jiangshan <laijs@cn.fujitsu.com>
AuthorDate: Thu, 2 Apr 2009 15:17:04 +0800
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Fri, 10 Apr 2009 12:44:44 +0200

tracing: update file->f_pos when splice(2) it

Impact: Cleanup

These two lines:

if (unlikely(*ppos))
return -ESPIPE;

in tracing_buffers_splice_read() are not needed, VFS layer
has disabled seek(2).

We remove these two lines, and then we can update file->f_pos.

And tracing_buffers_read() updates file->f_pos, this fix
make tracing_buffers_splice_read() updates file->f_pos too.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
LKML-Reference: <49D46670.4010503@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
kernel/trace/trace.c | 8 +-------
1 files changed, 1 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8e189ff..9462976 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3428,13 +3428,6 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
int size, i;
size_t ret;

- /*
- * We can't seek on a buffer input
- */
- if (unlikely(*ppos))
- return -ESPIPE;
-
-
for (i = 0; i < PIPE_BUFFERS && len; i++, len -= size) {
struct page *page;
int r;
@@ -3474,6 +3467,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
spd.partial[i].offset = 0;
spd.partial[i].private = (unsigned long)ref;
spd.nr_pages++;
+ *ppos += size;
}

spd.nr_pages = i;

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