The patch titled
Subject: proc: use initializer for clearing some buffers
has been added to the -mm mm-nonmm-unstable branch. Its filename is
proc-use-initializer-for-clearing-some-buffers.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/proc-use-initializer-for-clearing-some-buffers.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Subject: proc: use initializer for clearing some buffers
Date: Fri, 29 Sep 2023 19:30:18 +0300
Save LOC by using dark magic of initialisation instead of memset().
Those buffer aren't passed to userspace directly so padding is not
an issue.
Link: https://lkml.kernel.org/r/3821d3a2-6e10-4629-b0d5-9519d828ab72@p183
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/base.c | 16 ++++++----------
fs/proc/task_mmu.c | 11 +++--------
2 files changed, 9 insertions(+), 18 deletions(-)
--- a/fs/proc/base.c~proc-use-initializer-for-clearing-some-buffers
+++ a/fs/proc/base.c
@@ -1153,11 +1153,10 @@ err_unlock:
static ssize_t oom_adj_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
- char buffer[PROC_NUMBUF];
+ char buffer[PROC_NUMBUF] = {};
int oom_adj;
int err;
- memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count)) {
@@ -1213,11 +1212,10 @@ static ssize_t oom_score_adj_read(struct
static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
- char buffer[PROC_NUMBUF];
+ char buffer[PROC_NUMBUF] = {};
int oom_score_adj;
int err;
- memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count)) {
@@ -1358,13 +1356,13 @@ static ssize_t proc_fault_inject_write(s
const char __user * buf, size_t count, loff_t *ppos)
{
struct task_struct *task;
- char buffer[PROC_NUMBUF];
+ char buffer[PROC_NUMBUF] = {};
int make_it_fail;
int rv;
if (!capable(CAP_SYS_RESOURCE))
return -EPERM;
- memset(buffer, 0, sizeof(buffer));
+
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
@@ -1509,11 +1507,10 @@ sched_autogroup_write(struct file *file,
{
struct inode *inode = file_inode(file);
struct task_struct *p;
- char buffer[PROC_NUMBUF];
+ char buffer[PROC_NUMBUF] = {};
int nice;
int err;
- memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
@@ -1666,10 +1663,9 @@ static ssize_t comm_write(struct file *f
{
struct inode *inode = file_inode(file);
struct task_struct *p;
- char buffer[TASK_COMM_LEN];
+ char buffer[TASK_COMM_LEN] = {};
const size_t maxlen = sizeof(buffer) - 1;
- memset(buffer, 0, sizeof(buffer));
if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
return -EFAULT;
--- a/fs/proc/task_mmu.c~proc-use-initializer-for-clearing-some-buffers
+++ a/fs/proc/task_mmu.c
@@ -851,9 +851,7 @@ static void __show_smap(struct seq_file
static int show_smap(struct seq_file *m, void *v)
{
struct vm_area_struct *vma = v;
- struct mem_size_stats mss;
-
- memset(&mss, 0, sizeof(mss));
+ struct mem_size_stats mss = {};
smap_gather_stats(vma, &mss, 0);
@@ -879,7 +877,7 @@ static int show_smap(struct seq_file *m,
static int show_smaps_rollup(struct seq_file *m, void *v)
{
struct proc_maps_private *priv = m->private;
- struct mem_size_stats mss;
+ struct mem_size_stats mss = {};
struct mm_struct *mm = priv->mm;
struct vm_area_struct *vma;
unsigned long vma_start = 0, last_vma_end = 0;
@@ -895,8 +893,6 @@ static int show_smaps_rollup(struct seq_
goto out_put_task;
}
- memset(&mss, 0, sizeof(mss));
-
ret = mmap_read_lock_killable(mm);
if (ret)
goto out_put_mm;
@@ -1248,14 +1244,13 @@ static ssize_t clear_refs_write(struct f
size_t count, loff_t *ppos)
{
struct task_struct *task;
- char buffer[PROC_NUMBUF];
+ char buffer[PROC_NUMBUF] = {};
struct mm_struct *mm;
struct vm_area_struct *vma;
enum clear_refs_types type;
int itype;
int rv;
- memset(buffer, 0, sizeof(buffer));
if (count > sizeof(buffer) - 1)
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
_
Patches currently in -mm which might be from adobriyan@xxxxxxxxx are
extract-and-use-file_line-macro.patch
proc-use-initializer-for-clearing-some-buffers.patch
proc-save-loc-by-using-while-loop.patch
