What is "#define alloc_ieee80211 alloc_ieee80211_rsl"?

[valdis.kletnieks at vt.edu]

On Tue, 09 Oct 2018 20:07:08 +0100, John Whitmore said:

> #define alloc_ieee80211			alloc_ieee80211_rsl
>
> So what am I missing or why are a number of functions being redefined
> as another name, which doesn't exist?

There's areas in the kernel which use the preprocessor ## to glue stuff
together. see include/asm-generic/atomic-long.h  and ATOMIC_LONG_FETCH_OP for
an example. It's also use in some code to generate function names to initialize
a structure of function pointers.  This can make grepping for a function name
troublesome if you don't realize there's ## abuse going on to create a function
name on the fly.

However, in this particular case, it looks like they're redirecting an
allocator so that for rtl8192u, when common/copypasted code calls
alloc_ieee80211 it gets redirected to their own version...

[/usr/src/linux-next] git grep alloc_ieee80211
drivers/staging/rtl8192u/ieee80211/ieee80211.h:#define alloc_ieee80211                  alloc_ieee80211_rsl
drivers/staging/rtl8192u/ieee80211/ieee80211.h:  * allocated beyond this structure by alloc_ieee80211
drivers/staging/rtl8192u/ieee80211/ieee80211.h:struct net_device *alloc_ieee80211(int sizeof_priv);
drivers/staging/rtl8192u/ieee80211/ieee80211_module.c:struct net_device *alloc_ieee80211(int sizeof_priv)
drivers/staging/rtl8192u/r8192U_core.c: dev = alloc_ieee80211(sizeof(struct r8192_priv));


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