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| author |   Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-02 14:57:44 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-02 14:57:44 -0800 |
| commit | d3581c8ef718ae1b03e9106446ddf76b77026895 (patch) | |
| tree | bf8f1bb5afc691f7681cf7c79515c726127fd04c /drivers/firewire/ohci.c | |
| parent | Merge tag 'pinctrl-v4.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl (diff) | |
| parent | firewire-ohci: work around oversized DMA reads on JMicron controllers (diff) | |
| download | linux-dev-d3581c8ef718ae1b03e9106446ddf76b77026895.tar.xz linux-dev-d3581c8ef718ae1b03e9106446ddf76b77026895.zip | |
Merge tag 'firewire-updates' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394
Pull firewire updates from Stefan Richter
- make JMicron JMB38x controllers work with IOMMU-equipped systems
- IP-over-1394: allow user-configured MTU of up to 4096 bytes
* tag 'firewire-updates' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394:
firewire-ohci: work around oversized DMA reads on JMicron controllers
firewire: net: max MTU off by one
Diffstat (limited to 'drivers/firewire/ohci.c')
| -rw-r--r-- | drivers/firewire/ohci.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c index ccf52368a073..45c048751f3b 100644 --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -1128,7 +1128,13 @@ static int context_add_buffer(struct context *ctx) return -ENOMEM; offset = (void *)&desc->buffer - (void *)desc; - desc->buffer_size = PAGE_SIZE - offset; + /* + * Some controllers, like JMicron ones, always issue 0x20-byte DMA reads + * for descriptors, even 0x10-byte ones. This can cause page faults when + * an IOMMU is in use and the oversized read crosses a page boundary. + * Work around this by always leaving at least 0x10 bytes of padding. + */ + desc->buffer_size = PAGE_SIZE - offset - 0x10; desc->buffer_bus = bus_addr + offset; desc->used = 0; |