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Subject[ 064/109] posix_types.h: Cleanup stale __NFDBITS and related definitions
Date
From: Greg KH <gregkh@linuxfoundation.org>

3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Josh Boyer <jwboyer@redhat.com>

commit 8ded2bbc1845e19c771eb55209aab166ef011243 upstream.

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>
Signed-off-by: Josh Boyer <jwboyer@redhat.com>
[ .. and fix up whitespace as per akpm ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/mips/kernel/kspd.c | 2 +-
fs/exec.c | 2 +-
fs/select.c | 10 +++++-----
include/linux/posix_types.h | 18 +++---------------
include/linux/time.h | 8 --------
kernel/exit.c | 2 +-
security/selinux/hooks.c | 2 +-
7 files changed, 12 insertions(+), 32 deletions(-)

--- a/arch/mips/kernel/kspd.c
+++ b/arch/mips/kernel/kspd.c
@@ -323,7 +323,7 @@ static void sp_cleanup(void)
fdt = files_fdtable(files);
for (;;) {
unsigned long set;
- i = j * __NFDBITS;
+ i = j * BITS_PER_LONG;
if (i >= fdt->max_fds)
break;
set = fdt->open_fds[j++];
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1024,7 +1024,7 @@ static void flush_old_files(struct files
unsigned long set, i;

j++;
- i = j * __NFDBITS;
+ i = j * BITS_PER_LONG;
fdt = files_fdtable(files);
if (i >= fdt->max_fds)
break;
--- a/fs/select.c
+++ b/fs/select.c
@@ -345,8 +345,8 @@ static int max_select_fd(unsigned long n
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, s
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;
--- 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. */
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -258,14 +258,6 @@ static __always_inline void timespec_add

#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:
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -471,7 +471,7 @@ static void close_files(struct files_str
rcu_read_unlock();
for (;;) {
unsigned long set;
- i = j * __NFDBITS;
+ i = j * BITS_PER_LONG;
if (i >= fdt->max_fds)
break;
set = fdt->open_fds[j++];
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2162,7 +2162,7 @@ static inline void flush_unauthorized_fi
int fd;

j++;
- i = j * __NFDBITS;
+ i = j * BITS_PER_LONG;
fdt = files_fdtable(files);
if (i >= fdt->max_fds)
break;



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