| From 0193ed8225e1a79ed64632106ec3cc81798cb13c Mon Sep 17 00:00:00 2001 |
| From: Alexandre Bounine <alexandre.bounine@idt.com> |
| Date: Wed, 30 Jul 2014 16:08:26 -0700 |
| Subject: rapidio/tsi721_dma: fix failure to obtain transaction descriptor |
| |
| From: Alexandre Bounine <alexandre.bounine@idt.com> |
| |
| 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> |
| |
| --- |
| drivers/rapidio/devices/tsi721_dma.c | 8 +++++++- |
| 1 file changed, 7 insertions(+), 1 deletion(-) |
| |
| --- 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(s |
| "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(s |
| 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; |
