Date: Thu, 14 Jun 2018 09:58:50 +0200 From: Hans Petter Selasky <hps@selasky.org> To: Bruce Evans <bde@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r335053 - in head/sys: compat/freebsd32 compat/linux fs/nfsclient kern sys Message-ID: <35d80ebb-b505-59ed-2ee1-a0334090755e@selasky.org> In-Reply-To: <90566a73-c793-2cc4-27ac-039bf83fd2d0@selasky.org> References: <201806131222.w5DCM00c001080@repo.freebsd.org> <90566a73-c793-2cc4-27ac-039bf83fd2d0@selasky.org>
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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
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