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authorTakashi Iwai <tiwai@suse.de>2016-05-27 15:16:53 (GMT)
committerTakashi Iwai <tiwai@suse.de>2016-05-27 15:16:53 (GMT)
commiteb4606e64a7d548f5d60a9583baa8104890b2c6e (patch)
tree2dc8e587fc79c207dab2fb74830963cc84dcf801 /Documentation/networking/checksum-offloads.txt
parent86c72d1ce91d804e4fa8d90b316a89597dd220f1 (diff)
parentbf65921380cd50b87618df550398e06581f4a361 (diff)
downloadlinux-eb4606e64a7d548f5d60a9583baa8104890b2c6e.tar.xz
Merge tag 'asoc-v4.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
ASoC: Updates for v4.7 part 2 Really sorry about this late pull request. It looks like at the time I sent my pull request for v4.7 there was some conflict or other issue which caused my script to stop merging the ASoC branches at some point after the HDMI changes. It's all specific driver updates, including: - New drivers for MAX98371 and TAS5720. - SPI support for TLV320AIC32x4. - TDM support for STI Uniperf IPs. This code should all have been in -next prior to the merge window apart from some fixes, it dropped out on the 18th.
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-rw-r--r--Documentation/networking/checksum-offloads.txt14
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diff --git a/Documentation/networking/checksum-offloads.txt b/Documentation/networking/checksum-offloads.txt
index de2a327..56e3686 100644
--- a/Documentation/networking/checksum-offloads.txt
+++ b/Documentation/networking/checksum-offloads.txt
@@ -69,18 +69,18 @@ LCO: Local Checksum Offload
LCO is a technique for efficiently computing the outer checksum of an
encapsulated datagram when the inner checksum is due to be offloaded.
The ones-complement sum of a correctly checksummed TCP or UDP packet is
- equal to the sum of the pseudo header, because everything else gets
- 'cancelled out' by the checksum field. This is because the sum was
+ equal to the complement of the sum of the pseudo header, because everything
+ else gets 'cancelled out' by the checksum field. This is because the sum was
complemented before being written to the checksum field.
More generally, this holds in any case where the 'IP-style' ones complement
checksum is used, and thus any checksum that TX Checksum Offload supports.
That is, if we have set up TX Checksum Offload with a start/offset pair, we
- know that _after the device has filled in that checksum_, the ones
+ know that after the device has filled in that checksum, the ones
complement sum from csum_start to the end of the packet will be equal to
- _whatever value we put in the checksum field beforehand_. This allows us
- to compute the outer checksum without looking at the payload: we simply
- stop summing when we get to csum_start, then add the 16-bit word at
- (csum_start + csum_offset).
+ the complement of whatever value we put in the checksum field beforehand.
+ This allows us to compute the outer checksum without looking at the payload:
+ we simply stop summing when we get to csum_start, then add the complement of
+ the 16-bit word at (csum_start + csum_offset).
Then, when the true inner checksum is filled in (either by hardware or by
skb_checksum_help()), the outer checksum will become correct by virtue of
the arithmetic.