diff options
| author | FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> | 2010-03-31 02:35:50 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-04-02 06:53:12 +0400 |
| commit | 5acbbd428db47b12f137a8a2aa96b3c0a96b744e (patch) | |
| tree | 20ffdc4e418a086411f6fa8ff4ead2d488bda8da /net | |
| parent | 4fd89b7af28292e190650b9b9bc4308658d81dd1 (diff) | |
| download | linux-5acbbd428db47b12f137a8a2aa96b3c0a96b744e.tar.xz | |
net: change illegal_highdma to use dma_mask
Robert Hancock pointed out two problems about NETIF_F_HIGHDMA:
-Many drivers only set the flag when they detect they can use 64-bit DMA,
since otherwise they could receive DMA addresses that they can't handle
(which on platforms without IOMMU/SWIOTLB support is fatal). This means that if
64-bit support isn't available, even buffers located below 4GB will get copied
unnecessarily.
-Some drivers set the flag even though they can't actually handle 64-bit DMA,
which would mean that on platforms without IOMMU/SWIOTLB they would get a DMA
mapping error if the memory they received happened to be located above 4GB.
http://lkml.org/lkml/2010/3/3/530
We can use the dma_mask if we need bouncing or not here. Then we can
safely fix drivers that misuse NETIF_F_HIGHDMA.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/dev.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index 427cd53c118d..e19cdae49fef 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -129,6 +129,7 @@ #include <linux/jhash.h> #include <linux/random.h> #include <trace/events/napi.h> +#include <linux/pci.h> #include "net-sysfs.h" @@ -1804,14 +1805,21 @@ static inline int illegal_highdma(struct net_device *dev, struct sk_buff *skb) { #ifdef CONFIG_HIGHMEM int i; + if (!(dev->features & NETIF_F_HIGHDMA)) { + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) + if (PageHighMem(skb_shinfo(skb)->frags[i].page)) + return 1; + } - if (dev->features & NETIF_F_HIGHDMA) - return 0; - - for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) - if (PageHighMem(skb_shinfo(skb)->frags[i].page)) - return 1; + if (PCI_DMA_BUS_IS_PHYS) { + struct device *pdev = dev->dev.parent; + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { + dma_addr_t addr = page_to_phys(skb_shinfo(skb)->frags[i].page); + if (!pdev->dma_mask || addr + PAGE_SIZE - 1 > *pdev->dma_mask) + return 1; + } + } #endif return 0; } |