From 43f88d530ec656d9b556fb0d127b30757b1c3d35 Mon Sep 17 00:00:00 2001
From: Daniel Lichtenberger <daniel.lichtenberger@gmail.com>
Date: Thu, 28 Oct 2010 23:20:12 +0200
Subject: [PATCH] Staging: rtl8192e: fix IOMMU memory leak
Unmap the rx buffer before mapping the new one in rtl8192_rx.
Failing to do so quickly exhausts the IOMMU memory during downloads:
[...] DMA: Out of SW-IOMMU space for 9100 bytes at device ...
Using "iommu=off mem=4g" also fixes the problem because
then pci_map_single does not allocate memory.
Tested on my personal laptop with a RTL8192E device. Without this
patch the kernel quickly runs out of IOMMU memory (downloading 5 MB
of data is sufficient to trigger it), with this patch applied
I haven't experienced any issues so far.
Signed-off-by: Daniel Lichtenberger <daniel.lichtenberger@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/staging/rtl8192e/r8192E_core.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/staging/rtl8192e/r8192E_core.c b/drivers/staging/rtl8192e/r8192E_core.c
index a202194b5cbb1..b1786dcac2456 100644
--- a/drivers/staging/rtl8192e/r8192E_core.c
+++ b/drivers/staging/rtl8192e/r8192E_core.c
@@ -5829,6 +5829,9 @@ static void rtl8192_rx(struct net_device *dev)
}
}
+ pci_unmap_single(priv->pdev, *((dma_addr_t *) skb->cb),
+ priv->rxbuffersize, PCI_DMA_FROMDEVICE);
+
skb = new_skb;
priv->rx_buf[priv->rx_idx] = skb;
*((dma_addr_t *) skb->cb) = pci_map_single(priv->pdev, skb_tail_pointer(skb), priv->rxbuffersize, PCI_DMA_FROMDEVICE);