Messages in this thread | | | From | Arnd Bergmann <> | Date | Fri, 19 Jan 2018 21:42:17 +0100 | Subject | Re: [PATCH] NTB: ntb_perf: fix cast to restricted __le32 |
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On Fri, Jan 19, 2018 at 6:30 PM, Serge Semin <fancer.lancer@gmail.com> wrote: > Sparse is whining about the u32 and __le32 mixed usage in the > driver. > > drivers/ntb/test/ntb_perf.c:288:21: warning: cast to restricted __le32 > drivers/ntb/test/ntb_perf.c:295:37: warning: incorrect type in argument 4 (different base types) > drivers/ntb/test/ntb_perf.c:295:37: expected unsigned int [unsigned] [usertype] val > drivers/ntb/test/ntb_perf.c:295:37: got restricted __le32 [usertype] <noident> > ... > > The NTB API can't be changed so ntb_spad_*() methods > would return either pure __le32 or __be32, since the scratchpad > data can have arbitrary endianness in general. In this case we > need to forcibly cast all the u32 to be __le32 and vise-versa > where it's supposed to be in accordance with the driver logic. >
There's got to be a better way to do this than sprinkling lots of __force typecasts throughout the code.
It looks like all those casts are about ntb_peer_spad_read()/ntb_peer_msg_write() calls, so why not change those function prototypes to work on __le32 types?
There should also be some form of documentation regarding why you need to swap the data twice, since all the ntb drivers later end up doing another cpu_to_le32() on the little-endian data.
Arnd
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