Patchwork [2/4] powerpc/spufs: sputrace: don't block until the read buffer is full

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Submitter Jeremy Kerr
Date Oct. 16, 2008, midnight
Message ID <1224115255.764574.835386443990.2.gpush@pingu>
Download mbox | patch
Permalink /patch/4651/
State Accepted
Headers show

Comments

Jeremy Kerr - Oct. 16, 2008, midnight
Currently, read() on the sputrace buffer will only return data when
the user buffer is exhausted. This may mean that we never see the
end of the event log, unless we read() with exactly the right-sized
buffer.

This change makes sputrace_read not block if we have data ready to
return.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

---
 arch/powerpc/platforms/cell/spufs/sputrace.c |    5 +++++
 1 file changed, 5 insertions(+)

Patch

diff --git a/arch/powerpc/platforms/cell/spufs/sputrace.c b/arch/powerpc/platforms/cell/spufs/sputrace.c
index 50cae0c..a2460e2 100644
--- a/arch/powerpc/platforms/cell/spufs/sputrace.c
+++ b/arch/powerpc/platforms/cell/spufs/sputrace.c
@@ -80,6 +80,11 @@  static ssize_t sputrace_read(struct file *file, char __user *buf,
 		char tbuf[128];
 		int width;
 
+		/* If we have data ready to return, don't block waiting
+		 * for more */
+		if (cnt > 0 && sputrace_used() == 0)
+			break;
+
 		error = wait_event_interruptible(sputrace_wait,
 						 sputrace_used() > 0);
 		if (error)