posix_types: Remove fd_set macros

<asm/posix_types.h> includes a set of macros that operate on file
descriptors. Way long ago those were exported to user space, but
nowadays they are #ifdef __KERNEL__.

However, they are nothing but standard (nonatomic) bit operations, and
we already have optimized versions of bit operations in the kernel.
We can't include <linux/bitops.h> in <asm/posix_types.h> but we can
move the definitions to <linux/time.h> and define them there in terms
of standard kernel bitops.

[ v2: folds the following fixes in:

a) Stray space in __FD_SET(), reported by Andrew Morton
b) #include <linux/string.h> needed for memset(), reported by Tony Luck ]

Signed-off-by: H. Peter Anvin <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Cc: Arnd Bergmann <[e-mail]>
Cc: Tony Luck <[e-mail]>
Cc: Andrew Morton <[e-mail]>

include/asm-generic/posix_types.h

···
 typedef unsigned short	__kernel_uid16_t;
 typedef unsigned short	__kernel_gid16_t;
 
-#ifdef __KERNEL__
-
-#undef __FD_SET
-static inline void __FD_SET(unsigned long __fd, __kernel_fd_set *__fdsetp)
-{
-	unsigned long __tmp = __fd / __NFDBITS;
-	unsigned long __rem = __fd % __NFDBITS;
-	__fdsetp->fds_bits[__tmp] |= (1UL<<__rem);
-}
-
-#undef __FD_CLR
-static inline void __FD_CLR(unsigned long __fd, __kernel_fd_set *__fdsetp)
-{
-	unsigned long __tmp = __fd / __NFDBITS;
-	unsigned long __rem = __fd % __NFDBITS;
-	__fdsetp->fds_bits[__tmp] &= ~(1UL<<__rem);
-}
-
-#undef __FD_ISSET
-static inline int __FD_ISSET(unsigned long __fd, const __kernel_fd_set *__p)
-{
-	unsigned long __tmp = __fd / __NFDBITS;
-	unsigned long __rem = __fd % __NFDBITS;
-	return (__p->fds_bits[__tmp] & (1UL<<__rem)) != 0;
-}
-
-/*
- * This will unroll the loop for the normal constant case (8 ints,
- * for a 256-bit fd_set)
- */
-#undef __FD_ZERO
-static inline void __FD_ZERO(__kernel_fd_set *__p)
-{
-	unsigned long *__tmp = __p->fds_bits;
-	int __i;
-
-	if (__builtin_constant_p(__FDSET_LONGS)) {
-		switch (__FDSET_LONGS) {
-		case 16:
-			__tmp[ 0] = 0; __tmp[ 1] = 0;
-			__tmp[ 2] = 0; __tmp[ 3] = 0;
-			__tmp[ 4] = 0; __tmp[ 5] = 0;
-			__tmp[ 6] = 0; __tmp[ 7] = 0;
-			__tmp[ 8] = 0; __tmp[ 9] = 0;
-			__tmp[10] = 0; __tmp[11] = 0;
-			__tmp[12] = 0; __tmp[13] = 0;
-			__tmp[14] = 0; __tmp[15] = 0;
-			return;
-
-		case 8:
-			__tmp[ 0] = 0; __tmp[ 1] = 0;
-			__tmp[ 2] = 0; __tmp[ 3] = 0;
-			__tmp[ 4] = 0; __tmp[ 5] = 0;
-			__tmp[ 6] = 0; __tmp[ 7] = 0;
-			return;
-
-		case 4:
-			__tmp[ 0] = 0; __tmp[ 1] = 0;
-			__tmp[ 2] = 0; __tmp[ 3] = 0;
-			return;
-		}
-	}
-	__i = __FDSET_LONGS;
-	while (__i) {
-		__i--;
-		*__tmp = 0;
-		__tmp++;
-	}
-}
-
-#endif /* __KERNEL__ */
-
 #endif /* __ASM_GENERIC_POSIX_TYPES_H */

include/linux/time.h

···
 #include <linux/types.h>
 
 #ifdef __KERNEL__
+# include <linux/bitops.h>
 # include <linux/cache.h>
+# include <linux/posix_types.h>
 # include <linux/seqlock.h>
+# include <linux/string.h>
 # include <linux/math64.h>
 #endif
 
···
 	a->tv_sec += __iter_div_u64_rem(a->tv_nsec + ns, NSEC_PER_SEC, &ns);
 	a->tv_nsec = ns;
 }
+
+static inline void __FD_SET(unsigned long __fd, __kernel_fd_set *__fdsetp)
+{
+	__set_bit(__fd, __fdsetp->fds_bits);
+}
+
+static inline void __FD_CLR(unsigned long __fd, __kernel_fd_set *__fdsetp)
+{
+	__clear_bit(__fd, __fdsetp->fds_bits);
+}
+
+static inline int __FD_ISSET(unsigned long __fd, const __kernel_fd_set *__fdsetp)
+{
+	return test_bit(__fd, __fdsetp->fds_bits);
+}
+
+static inline void __FD_ZERO(__kernel_fd_set *__fdsetp)
+{
+	memset(__fdsetp->fds_bits, 0, sizeof __fdsetp->fds_bits);
+}
+
 #endif /* __KERNEL__ */
 
 #define NFDBITS			__NFDBITS