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authorAlexandre Bounine <alexandre.bounine@idt.com>2014-07-30 16:08:26 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-08-07 14:30:25 -0700
commit7bfa5bfd88fb4c11a78740ea53509cc38b896d84 (patch)
tree04bd5ae1a8a15b8308ba00ffdc6334b2c7102896
parent201c26e77bfc4064afc6a630fc336a825047be7b (diff)
rapidio/tsi721_dma: fix failure to obtain transaction descriptor
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@idt.com> Cc: Matt Porter <mporter@kernel.crashing.org> Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com> Cc: Stef van Os <stef.van.os@prodrive-technologies.com> Cc: Vinod Koul <vinod.koul@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/rapidio/devices/tsi721_dma.c8
1 files changed, 7 insertions, 1 deletions
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;