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>

1 files changed, 5 insertions, 5 deletions

diff --git a/fs/select.c b/fs/select.c
index bae321569df..db14c781335 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -345,8 +345,8 @@ static int max_select_fd(unsigned long n, fd_set_bits *fds)
         struct fdtable *fdt;
 
         /* handle last in-complete long-word first */
-        set = ~(~0UL << (n & (__NFDBITS-1)));
-        n /= __NFDBITS;
+        set = ~(~0UL << (n & (BITS_PER_LONG-1)));
+        n /= BITS_PER_LONG;
         fdt = files_fdtable(current->files);
         open_fds = fdt->open_fds + n;
         max = 0;
@@ -373,7 +373,7 @@ get_max:
                         max++;
                         set >>= 1;
                 } while (set);
-                max += n * __NFDBITS;
+                max += n * BITS_PER_LONG;
         }
 
         return max;
@@ -435,11 +435,11 @@ int do_select(int n, fd_set_bits *fds, struct timespec *end_time)
                         in = *inp++; out = *outp++; ex = *exp++;
                         all_bits = in | out | ex;
                         if (all_bits == 0) {
-                                i += __NFDBITS;
+                                i += BITS_PER_LONG;
                                 continue;
                         }
 
-                        for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
+                        for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) {
                                 int fput_needed;
                                 if (i >= n)
                                         break;