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authorLinus Torvalds <torvalds@linux-foundation.org>2018-02-02 14:57:44 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-02 14:57:44 -0800
commitd3581c8ef718ae1b03e9106446ddf76b77026895 (patch)
treebf8f1bb5afc691f7681cf7c79515c726127fd04c /drivers/firewire/ohci.c
parentef991796be0e65b644fe60198bd1112830eff173 (diff)
parent188775181bc05f29372b305ef96485840e351fde (diff)
downloadlinux-d3581c8ef718ae1b03e9106446ddf76b77026895.tar.gz
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.c8
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;