+commit d4426800f71e972feaa33e04c5801fc730627bdd
+Author: Stanislaw Gruszka <stf_xl@wp.pl>
+Date: Mon Feb 10 22:38:28 2014 +0100
+
+ rtl8187: fix regression on MIPS without coherent DMA
+
+ This patch fixes regression caused by commit a16dad77634 "MIPS: Fix
+ potencial corruption". That commit fixes one corruption scenario in
+ cost of adding another one, which actually start to cause crashes
+ on Yeeloong laptop when rtl8187 driver is used.
+
+ For correct DMA read operation on machines without DMA coherence, kernel
+ have to invalidate cache, such it will refill later with new data that
+ device wrote to memory, when that data is needed to process. We can only
+ invalidate full cache line. Hence when cache line includes both dma
+ buffer and some other data (written in cache, but not yet in main
+ memory), the other data can not hit memory due to invalidation. That
+ happen on rtl8187 where struct rtl8187_priv fields are located just
+ before and after small buffers that are passed to USB layer and DMA
+ is performed on them.
+
+ To fix the problem we align buffers and reserve space after them to make
+ them match cache line.
+
+ This patch does not resolve all possible MIPS problems entirely, for
+ that we have to assure that we always map cache aligned buffers for DMA,
+ what can be complex or even not possible. But patch fixes visible and
+ reproducible regression and seems other possible corruptions do not
+ happen in practice, since Yeeloong laptop works stable without rtl8187
+ driver.
+
+ Bug report:
+ https://bugzilla.kernel.org/show_bug.cgi?id=54391
+
+ Reported-by: Petr Pisar <petr.pisar@atlas.cz>
+ Bisected-by: Tom Li <biergaizi2009@gmail.com>
+ Reported-and-tested-by: Tom Li <biergaizi2009@gmail.com>
+ Cc: stable@vger.kernel.org
+ Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
+