From: Alexandre Bounine <alexandre.bounine@xxxxxxx>
This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.
===============
commit 0193ed8225e1a79ed64632106ec3cc81798cb13c upstream.
This is a bug fix for the situation when function tsi721_desc_get() fails
to obtain a free transaction descriptor.
The bug usually results in a memory access crash dump when data transfer
scatter-gather list has more entries than size of hardware buffer
descriptors ring. This fix ensures that error is properly returned to a
caller instead of an invalid entry.
This patch is applicable to kernel versions starting from v3.5.
Signed-off-by: Alexandre Bounine <alexandre.bounine@xxxxxxx>
Cc: Matt Porter <mporter@xxxxxxxxxxxxxxxxxxx>
Cc: Andre van Herk <andre.van.herk@xxxxxxxxxxxxxxxxxxxxxxxxx>
Cc: Stef van Os <stef.van.os@xxxxxxxxxxxxxxxxxxxxxxxxx>
Cc: Vinod Koul <vinod.koul@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/rapidio/devices/tsi721_dma.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/rapidio/devices/tsi721_dma.c b/drivers/rapidio/devices/tsi721_dma.c
index 91245f5dbe81..47257b6eea84 100644
--- a/drivers/rapidio/devices/tsi721_dma.c
+++ b/drivers/rapidio/devices/tsi721_dma.c
@@ -287,6 +287,12 @@ struct tsi721_tx_desc *tsi721_desc_get(struct tsi721_bdma_chan *bdma_chan)
"desc %p not ACKed\n", tx_desc);
}
+ if (ret == NULL) {
+ dev_dbg(bdma_chan->dchan.device->dev,
+ "%s: unable to obtain tx descriptor\n", __func__);
+ goto err_out;
+ }
+
i = bdma_chan->wr_count_next % bdma_chan->bd_num;
if (i == bdma_chan->bd_num - 1) {
i = 0;
@@ -297,7 +303,7 @@ struct tsi721_tx_desc *tsi721_desc_get(struct tsi721_bdma_chan *bdma_chan)
tx_desc->txd.phys = bdma_chan->bd_phys +
i * sizeof(struct tsi721_dma_desc);
tx_desc->hw_desc = &((struct tsi721_dma_desc *)bdma_chan->bd_base)[i];
-
+err_out:
spin_unlock_bh(&bdma_chan->lock);
return ret;
--
2.0.4
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