posix_types.h: Cleanup stale __NFDBITS and related definitions

Recently, glibc made a change to suppress sign-conversion warnings in
FD_SET (glibc commit ceb9e56b3d1).  This uncovered an issue with the
kernel's definition of __NFDBITS if applications #include
<linux/types.h> after including <sys/select.h>.  A build failure would
be seen when passing the -Werror=sign-compare and -D_FORTIFY_SOURCE=2
flags to gcc.

It was suggested that the kernel should either match the glibc
definition of __NFDBITS or remove that entirely.  The current in-kernel
uses of __NFDBITS can be replaced with BITS_PER_LONG, and there are no
uses of the related __FDELT and __FDMASK defines.  Given that, we'll
continue the cleanup that was started with commit 8b3d1cda4f5f
("posix_types: Remove fd_set macros") and drop the remaining unused
macros.

Additionally, linux/time.h has similar macros defined that expand to
nothing so we'll remove those at the same time.

Reported-by: Jeff Law <law@redhat.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
CC: <stable@vger.kernel.org>
Signed-off-by: Josh Boyer <jwboyer@redhat.com>
[ .. and fix up whitespace as per akpm ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 3 insertions, 23 deletions

diff --git a/include/linux/posix_types.h b/include/linux/posix_types.h
index f04c98cf44f3..988f76e636e3 100644
--- a/include/linux/posix_types.h
+++ b/include/linux/posix_types.h
@@ -15,26 +15,14 @@
  */
 
 /*
- * Those macros may have been defined in <gnu/types.h>. But we always
- * use the ones here. 
+ * This macro may have been defined in <gnu/types.h>. But we always
+ * use the one here.
  */
-#undef __NFDBITS
-#define __NFDBITS       (8 * sizeof(unsigned long))
-
 #undef __FD_SETSIZE
 #define __FD_SETSIZE    1024
 
-#undef __FDSET_LONGS
-#define __FDSET_LONGS   (__FD_SETSIZE/__NFDBITS)
-
-#undef __FDELT
-#define __FDELT(d)      ((d) / __NFDBITS)
-
-#undef __FDMASK
-#define __FDMASK(d)     (1UL << ((d) % __NFDBITS))
-
 typedef struct {
-        unsigned long fds_bits [__FDSET_LONGS];
+        unsigned long fds_bits[__FD_SETSIZE / (8 * sizeof(long))];
 } __kernel_fd_set;
 
 /* Type of a signal handler.  */
diff --git a/include/linux/time.h b/include/linux/time.h
index 179f4d6755fc..c81c5e40fcb5 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -257,14 +257,6 @@ static __always_inline void timespec_add_ns(struct timespec *a, u64 ns)
 
 #endif /* __KERNEL__ */
 
-#define NFDBITS                 __NFDBITS
-
-#define FD_SETSIZE              __FD_SETSIZE
-#define FD_SET(fd,fdsetp)       __FD_SET(fd,fdsetp)
-#define FD_CLR(fd,fdsetp)       __FD_CLR(fd,fdsetp)
-#define FD_ISSET(fd,fdsetp)     __FD_ISSET(fd,fdsetp)
-#define FD_ZERO(fdsetp)         __FD_ZERO(fdsetp)
-
 /*
  * Names of the interval timers, and structure
  * defining a timer setting: