svn commit: r335053 - in head/sys: compat/freebsd32 compat/linux fs/nfsclient kern sys

[Hans Petter Selasky]

On 06/14/18 09:29, Hans Petter Selasky wrote:
> On 06/13/18 14:22, Bruce Evans wrote:
>> +/*
>> + * The major and minor numbers are encoded in dev_t as MMMmmmMm (where
>> + * letters correspond to bytes).  The encoding of the lower 4 bytes is
>> + * constrained by compatibility with 16-bit and 32-bit dev_t's.  The
>> + * encoding of of the upper 4 bytes is the least unnatural one 
>> consistent
>> + * with this and other constraints.  Also, the decoding of the m 
>> bytes by
>> + * minor() is unnatural to maximize compatibility subject to not 
>> discarding
>> + * bits.  The upper m byte is shifted into the position of the lower 
>> M byte
>> + * instead of shifting 3 upper m bytes to close the gap.  
>> Compatibility for
>> + * minor() is achieved iff the upper m byte is 0.
>> + */
>> +#define    major(d)    __major(d)
>> +static __inline int
>> +__major(dev_t _d)
>> +{
>> +    return (((_d >> 32) & 0xffffff00) | ((_d >> 8) & 0xff));
>> +}
>> +#define    minor(d)    __minor(d)
>> +static __inline int
>> +__minor(dev_t _d)
>> +{
>> +    return (((_d >> 24) & 0xff00) | (_d & 0xffff00ff));
>> +}
>> +#define    makedev(M, m)    __makedev((M), (m))
>> +static __inline dev_t
>> +__makedev(int _M, int _m)
>> +{
>> +    return (((dev_t)(_M & 0xffffff00) << 32) | ((_M & 0xff) << 8) |
>> +        ((dev_t)(_m & 0xff00) << 24) | (_m & 0xffff00ff));
>> +}
> 
> Can you use all macros here? This breaks OFED, because __makedev() is 
> used to initialize variables.

r335123 fixes this for OFED, but there might be other places where 
MAKDEV() is used to setup static and const variables.

--HPS