The patch titled
Subject: proc: use %u for pid printing and slightly less stack
has been added to the -mm tree. Its filename is
proc-use-%u-for-pid-printing-and-slightly-less-stack.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/proc-use-%25u-for-pid-printing-and-slightly-less-stack.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/proc-use-%25u-for-pid-printing-and-slightly-less-stack.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
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------------------------------------------------------
From: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Subject: proc: use %u for pid printing and slightly less stack
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@xxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/base.c | 16 ++++++++--------
fs/proc/fd.c | 2 +-
fs/proc/self.c | 6 +++---
fs/proc/thread_self.c | 5 ++---
4 files changed, 14 insertions(+), 15 deletions(-)
diff -puN fs/proc/base.c~proc-use-%u-for-pid-printing-and-slightly-less-stack fs/proc/base.c
--- a/fs/proc/base.c~proc-use-%u-for-pid-printing-and-slightly-less-stack
+++ a/fs/proc/base.c
@@ -3019,11 +3019,11 @@ static const struct inode_operations pro
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) {
@@ -3035,7 +3035,7 @@ static void proc_flush_task_mnt(struct v
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;
@@ -3047,7 +3047,7 @@ static void proc_flush_task_mnt(struct v
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);
@@ -3226,14 +3226,14 @@ int proc_pid_readdir(struct file *file,
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)) {
@@ -3561,10 +3561,10 @@ static int proc_task_readdir(struct file
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
diff -puN fs/proc/fd.c~proc-use-%u-for-pid-printing-and-slightly-less-stack fs/proc/fd.c
--- a/fs/proc/fd.c~proc-use-%u-for-pid-printing-and-slightly-less-stack
+++ a/fs/proc/fd.c
@@ -236,7 +236,7 @@ static int proc_readfd_common(struct fil
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))
diff -puN fs/proc/self.c~proc-use-%u-for-pid-printing-and-slightly-less-stack fs/proc/self.c
--- a/fs/proc/self.c~proc-use-%u-for-pid-printing-and-slightly-less-stack
+++ a/fs/proc/self.c
@@ -17,11 +17,11 @@ static const char *proc_self_get_link(st
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;
}
diff -puN fs/proc/thread_self.c~proc-use-%u-for-pid-printing-and-slightly-less-stack fs/proc/thread_self.c
--- a/fs/proc/thread_self.c~proc-use-%u-for-pid-printing-and-slightly-less-stack
+++ a/fs/proc/thread_self.c
@@ -18,11 +18,10 @@ static const char *proc_thread_self_get_
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;
}
_
Patches currently in -mm which might be from adobriyan@xxxxxxxxx are
proc-use-%u-for-pid-printing-and-slightly-less-stack.patch
proc-dont-use-read_once-write_once-for-proc-fail-nth.patch
proc-fix-proc-map_files-lookup.patch
seq_file-delete-small-value-optimization.patch
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