[PATCH 1/2] fs/file: more unsigned file descriptors

From: Alexey Dobriyan
Date: Thu Sep 01 2016 - 17:39:44 EST


Propagate unsignedness for grand total of 149 bytes:

$ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux
add/remove: 0/0 grow/shrink: 0/10 up/down: 0/-149 (-149)
function old new delta
set_close_on_exec 99 98 -1
put_files_struct 201 200 -1
get_close_on_exec 59 58 -1
do_prlimit 498 497 -1
do_execveat_common.isra 1662 1661 -1
__close_fd 178 173 -5
do_dup2 219 204 -15
seq_show 685 660 -25
__alloc_fd 384 357 -27
dup_fd 718 646 -72

It mostly comes from converting "unsigned int" to "long" for bit operations.

Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
---

fs/file.c | 34 +++++++++++++++++-----------------
include/linux/fdtable.h | 6 +++---
include/linux/fs.h | 2 +-
kernel/sysctl.c | 4 ++--
4 files changed, 23 insertions(+), 23 deletions(-)

--- a/fs/file.c
+++ b/fs/file.c
@@ -23,12 +23,12 @@
#include <linux/rcupdate.h>
#include <linux/workqueue.h>

-int sysctl_nr_open __read_mostly = 1024*1024;
-int sysctl_nr_open_min = BITS_PER_LONG;
+unsigned int sysctl_nr_open __read_mostly = 1024*1024;
+unsigned int sysctl_nr_open_min = BITS_PER_LONG;
/* our min() is unusable in constant expressions ;-/ */
#define __const_min(x, y) ((x) < (y) ? (x) : (y))
-int sysctl_nr_open_max = __const_min(INT_MAX, ~(size_t)0/sizeof(void *)) &
- -BITS_PER_LONG;
+unsigned int sysctl_nr_open_max =
+ __const_min(INT_MAX, ~(size_t)0/sizeof(void *)) & -BITS_PER_LONG;

static void *alloc_fdmem(size_t size)
{
@@ -163,7 +163,7 @@ out:
* Return <0 error code on error; 1 on successful completion.
* The files->file_lock should be held on entry, and will be held on exit.
*/
-static int expand_fdtable(struct files_struct *files, int nr)
+static int expand_fdtable(struct files_struct *files, unsigned int nr)
__releases(files->file_lock)
__acquires(files->file_lock)
{
@@ -208,7 +208,7 @@ static int expand_fdtable(struct files_struct *files, int nr)
* expanded and execution may have blocked.
* The files->file_lock should be held on entry, and will be held on exit.
*/
-static int expand_files(struct files_struct *files, int nr)
+static int expand_files(struct files_struct *files, unsigned int nr)
__releases(files->file_lock)
__acquires(files->file_lock)
{
@@ -243,12 +243,12 @@ repeat:
return expanded;
}

-static inline void __set_close_on_exec(int fd, struct fdtable *fdt)
+static inline void __set_close_on_exec(unsigned int fd, struct fdtable *fdt)
{
__set_bit(fd, fdt->close_on_exec);
}

-static inline void __clear_close_on_exec(int fd, struct fdtable *fdt)
+static inline void __clear_close_on_exec(unsigned int fd, struct fdtable *fdt)
{
if (test_bit(fd, fdt->close_on_exec))
__clear_bit(fd, fdt->close_on_exec);
@@ -268,10 +268,10 @@ static inline void __clear_open_fd(unsigned int fd, struct fdtable *fdt)
__clear_bit(fd / BITS_PER_LONG, fdt->full_fds_bits);
}

-static int count_open_files(struct fdtable *fdt)
+static unsigned int count_open_files(struct fdtable *fdt)
{
- int size = fdt->max_fds;
- int i;
+ unsigned int size = fdt->max_fds;
+ unsigned int i;

/* Find the last open fd */
for (i = size / BITS_PER_LONG; i > 0; ) {
@@ -291,7 +291,7 @@ struct files_struct *dup_fd(struct files_struct *oldf, int *errorp)
{
struct files_struct *newf;
struct file **old_fds, **new_fds;
- int open_files, i;
+ unsigned int open_files, i;
struct fdtable *old_fdt, *new_fdt;

*errorp = -ENOMEM;
@@ -391,7 +391,7 @@ static struct fdtable *close_files(struct files_struct * files)
* files structure.
*/
struct fdtable *fdt = rcu_dereference_raw(files->fdt);
- int i, j = 0;
+ unsigned int i, j = 0;

for (;;) {
unsigned long set;
@@ -477,11 +477,11 @@ struct files_struct init_files = {
.file_lock = __SPIN_LOCK_UNLOCKED(init_files.file_lock),
};

-static unsigned long find_next_fd(struct fdtable *fdt, unsigned long start)
+static unsigned int find_next_fd(struct fdtable *fdt, unsigned int start)
{
- unsigned long maxfd = fdt->max_fds;
- unsigned long maxbit = maxfd / BITS_PER_LONG;
- unsigned long bitbit = start / BITS_PER_LONG;
+ unsigned int maxfd = fdt->max_fds;
+ unsigned int maxbit = maxfd / BITS_PER_LONG;
+ unsigned int bitbit = start / BITS_PER_LONG;

bitbit = find_next_zero_bit(fdt->full_fds_bits, maxbit, bitbit) * BITS_PER_LONG;
if (bitbit > maxfd)
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -30,12 +30,12 @@ struct fdtable {
struct rcu_head rcu;
};

-static inline bool close_on_exec(int fd, const struct fdtable *fdt)
+static inline bool close_on_exec(unsigned int fd, const struct fdtable *fdt)
{
return test_bit(fd, fdt->close_on_exec);
}

-static inline bool fd_is_open(int fd, const struct fdtable *fdt)
+static inline bool fd_is_open(unsigned int fd, const struct fdtable *fdt)
{
return test_bit(fd, fdt->open_fds);
}
@@ -57,7 +57,7 @@ struct files_struct {
* written part on a separate cache line in SMP
*/
spinlock_t file_lock ____cacheline_aligned_in_smp;
- int next_fd;
+ unsigned int next_fd;
unsigned long close_on_exec_init[1];
unsigned long open_fds_init[1];
unsigned long full_fds_bits_init[1];
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -63,7 +63,7 @@ extern void __init files_maxfiles_init(void);

extern struct files_stat_struct files_stat;
extern unsigned long get_max_files(void);
-extern int sysctl_nr_open;
+extern unsigned int sysctl_nr_open;
extern struct inodes_stat_t inodes_stat;
extern int leases_enable, lease_break_time;
extern int sysctl_protected_symlinks;
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -108,7 +108,7 @@ extern int pid_max_min, pid_max_max;
extern int percpu_pagelist_fraction;
extern int compat_log;
extern int latencytop_enabled;
-extern int sysctl_nr_open_min, sysctl_nr_open_max;
+extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
#ifndef CONFIG_MMU
extern int sysctl_nr_trim_pages;
#endif
@@ -1692,7 +1692,7 @@ static struct ctl_table fs_table[] = {
{
.procname = "nr_open",
.data = &sysctl_nr_open,
- .maxlen = sizeof(int),
+ .maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = &sysctl_nr_open_min,