[PATCH] Fix staging:iio:ring_sw: Fix incorrect test on successful read of last value, causes infinite loop

[PATCH] Fix staging:iio:ring_sw: Fix incorrect test on successful read of last value, causes infinite loop

[Jonathan Cameron]

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
---

 This is a bad one. The test means that almost no reads of the last
 value ever succeed!  Result is an infinite loop.

 Another one for the 'oops' category.

 Patch is post the spin lock fix:
 [PATCH] Staging: IIO: Fix uses of spinlocks prior to init in ring implementations


 drivers/staging/iio/ring_sw.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/staging/iio/ring_sw.c b/drivers/staging/iio/ring_sw.c
index 7dff2bf..5abba8c 100644
--- a/drivers/staging/iio/ring_sw.c
+++ b/drivers/staging/iio/ring_sw.c
@@ -296,7 +296,7 @@ again:
 		return -EAGAIN;
 	memcpy(data, last_written_p_copy, ring->buf.bpd);
 
-	if (unlikely(ring->last_written_p >= last_written_p_copy))
+	if (unlikely(ring->last_written_p != last_written_p_copy))
 		goto again;
 
 	iio_unmark_sw_rb_in_use(&ring->buf);
-- 
1.6.4.4