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proc: use %u for pid printing and slightly less stack

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PROC_NUMBUF is 13 which is enough for "negative int + \n + \0".

However PIDs and TGIDs are never negative and newline is not a concern,
so use just 10 per integer.

Link: http://lkml.kernel.org/r/20171120203005.GA27743@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alexander Viro <viro@ftp.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexey Dobriyan 2018-02-06 15:36:51 -08:00 committed by Linus Torvalds
parent 48c2323954
commit e3912ac37e
4 changed files with 14 additions and 15 deletions
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16
fs/proc/base.c
View File

@ -3018,11 +3018,11 @@ static const struct inode_operations proc_tgid_base_inode_operations = {
static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
{
struct dentry *dentry, *leader, *dir;
char buf[PROC_NUMBUF];
char buf[10 + 1];
struct qstr name;
name.name = buf;
name.len = snprintf(buf, sizeof(buf), "%d", pid);
name.len = snprintf(buf, sizeof(buf), "%u", pid);
/* no ->d_hash() rejects on procfs */
dentry = d_hash_and_lookup(mnt->mnt_root, &name);
if (dentry) {
@ -3034,7 +3034,7 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
return;
name.name = buf;
name.len = snprintf(buf, sizeof(buf), "%d", tgid);
name.len = snprintf(buf, sizeof(buf), "%u", tgid);
leader = d_hash_and_lookup(mnt->mnt_root, &name);
if (!leader)
goto out;
@ -3046,7 +3046,7 @@ static void proc_flush_task_mnt(struct vfsmount *mnt, pid_t pid, pid_t tgid)
goto out_put_leader;
name.name = buf;
name.len = snprintf(buf, sizeof(buf), "%d", pid);
name.len = snprintf(buf, sizeof(buf), "%u", pid);
dentry = d_hash_and_lookup(dir, &name);
if (dentry) {
d_invalidate(dentry);
@ -3225,14 +3225,14 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx)
for (iter = next_tgid(ns, iter);
iter.task;
iter.tgid += 1, iter = next_tgid(ns, iter)) {
char name[PROC_NUMBUF];
char name[10 + 1];
int len;
cond_resched();
if (!has_pid_permissions(ns, iter.task, HIDEPID_INVISIBLE))
continue;
len = snprintf(name, sizeof(name), "%d", iter.tgid);
len = snprintf(name, sizeof(name), "%u", iter.tgid);
ctx->pos = iter.tgid + TGID_OFFSET;
if (!proc_fill_cache(file, ctx, name, len,
proc_pid_instantiate, iter.task, NULL)) {
@ -3560,10 +3560,10 @@ static int proc_task_readdir(struct file *file, struct dir_context *ctx)
for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
task;
task = next_tid(task), ctx->pos++) {
char name[PROC_NUMBUF];
char name[10 + 1];
int len;
tid = task_pid_nr_ns(task, ns);
len = snprintf(name, sizeof(name), "%d", tid);
len = snprintf(name, sizeof(name), "%u", tid);
if (!proc_fill_cache(file, ctx, name, len,
proc_task_instantiate, task, NULL)) {
/* returning this tgid failed, save it as the first

2
fs/proc/fd.c
View File

@ -236,7 +236,7 @@ static int proc_readfd_common(struct file *file, struct dir_context *ctx,
for (fd = ctx->pos - 2;
fd < files_fdtable(files)->max_fds;
fd++, ctx->pos++) {
char name[PROC_NUMBUF];
char name[10 + 1];
int len;
if (!fcheck_files(files, fd))

6
fs/proc/self.c
View File

@ -17,11 +17,11 @@ static const char *proc_self_get_link(struct dentry *dentry,
if (!tgid)
return ERR_PTR(-ENOENT);
/* 11 for max length of signed int in decimal + NULL term */
name = kmalloc(12, dentry ? GFP_KERNEL : GFP_ATOMIC);
/* max length of unsigned int in decimal + NULL term */
name = kmalloc(10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
if (unlikely(!name))
return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
sprintf(name, "%d", tgid);
sprintf(name, "%u", tgid);
set_delayed_call(done, kfree_link, name);
return name;
}

5
fs/proc/thread_self.c
View File

@ -18,11 +18,10 @@ static const char *proc_thread_self_get_link(struct dentry *dentry,
if (!pid)
return ERR_PTR(-ENOENT);
name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF,
dentry ? GFP_KERNEL : GFP_ATOMIC);
name = kmalloc(10 + 6 + 10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
if (unlikely(!name))
return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
sprintf(name, "%d/task/%d", tgid, pid);
sprintf(name, "%u/task/%u", tgid, pid);
set_delayed_call(done, kfree_link, name);
return name;
}