Ping Re: Fix bits/socket.h IOC* namespace issues (bug 21267)

[Joseph Myers]

On Fri, 24 Mar 2017, Arnd Bergmann wrote:

> There are many exported or user-space provided headers that include
> linux/ioctl.h or asm/ioctl.h in order to get the _IOC/IOW/IOR/IOWR
> macros:

That's what I expect them to be used for.

> so any of them will also pull in IOC_IN/INOUT/OUT.  Is mips/asm/sockios.h
> the only one in that list that i  problematic for glibc, or should they
> all avoid the  macros if possible?

Only mips/asm/sockios.h is currently observed to cause namespace problems.  
alpha's asm/sockios.h also uses _IOR/_IOW macros, but without including 
<asm/ioctl.h> (so I suppose the macros defined using _IOR/_IOW might not 
actually work unless a source of those macro definitions gets included 
explicitly).

-- 
Joseph S. Myers
joseph@codesourcery.com