Re: svn commit: r335053 - in head/sys: compat/freebsd32 compat/linux fs/nfsclient kern sys
On Thu, 14 Jun 2018, Hans Petter Selasky wrote: On 06/13/18 14:22, Bruce Evans wrote: [... inlines for makedev(), etc.] Can you use all macros here? This breaks OFED, because __makedev() is used to initialize variables. See another reply. I will change them to macros and fear breaking them with a gccism instead of with with inlines. I should have worried more about the inlines. Plain inline is only in C99 or a gcc extension starting in gcc-2.mumble. Portability of sys/types.h is more important than for any other header in the system except sys/cdevs.h. So it must compile with C90 compilers and should compile with K compilers. For makedev(), etc., it spells inline as __inline so the inline feature can be turned off easily (the functions then become static and repeated every time sys/types.h is included, but this probably happens anyway with -O0 and it works for any compiler). Turning off the statement-expression feature needed to write safe macros is not so easy. In , this feature is only used in mostly-kernel headers and in stdatomic.h. Bruce ___ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
Re: svn commit: r335053 - in head/sys: compat/freebsd32 compat/linux fs/nfsclient kern sys
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) & 0xff00) | ((_d >> 8) & 0xff));
+}
+#define minor(d) __minor(d)
+static __inline int
+__minor(dev_t _d)
+{
+ return (((_d >> 24) & 0xff00) | (_d & 0x00ff));
+}
+#define makedev(M, m) __makedev((M), (m))
+static __inline dev_t
+__makedev(int _M, int _m)
+{
+ return (((dev_t)(_M & 0xff00) << 32) | ((_M & 0xff) << 8) |
+ ((dev_t)(_m & 0xff00) << 24) | (_m & 0x00ff));
+}
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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Re: svn commit: r335053 - in head/sys: compat/freebsd32 compat/linux fs/nfsclient kern sys
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.
+ */
+#definemajor(d)__major(d)
+static __inline int
+__major(dev_t _d)
+{
+ return (((_d >> 32) & 0xff00) | ((_d >> 8) & 0xff));
+}
+#defineminor(d)__minor(d)
+static __inline int
+__minor(dev_t _d)
+{
+ return (((_d >> 24) & 0xff00) | (_d & 0x00ff));
+}
+#definemakedev(M, m) __makedev((M), (m))
+static __inline dev_t
+__makedev(int _M, int _m)
+{
+ return (((dev_t)(_M & 0xff00) << 32) | ((_M & 0xff) << 8) |
+ ((dev_t)(_m & 0xff00) << 24) | (_m & 0x00ff));
+}
Can you use all macros here? This breaks OFED, because __makedev() is
used to initialize variables.
--HPS
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