From: Alexey Dobriyan <adobriyan@gmail.com>
Date: Fri, 29 Sep 2023 16:30:18 +0000 (+0300)
Subject: proc: use initializer for clearing some buffers
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=860a2e7fa4a186a78be904879f752858c96328ed;p=linux.git

proc: use initializer for clearing some buffers

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@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/fs/proc/base.c b/fs/proc/base.c
index c0e971cc6d41c..601329f9629a0 100644
--- a/fs/proc/base.c
+++ b/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 file *file, char __user *buf,
 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(struct file * file,
 			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, const char __user *buf,
 {
 	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 *file, const char __user *buf,
 {
 	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;
 
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 3dd5be96691b4..d4d55d5bae51b 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -849,9 +849,7 @@ static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss,
 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);
 
@@ -877,7 +875,7 @@ static int show_smap(struct seq_file *m, void *v)
 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;
@@ -893,8 +891,6 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
 		goto out_put_task;
 	}
 
-	memset(&mss, 0, sizeof(mss));
-
 	ret = mmap_read_lock_killable(mm);
 	if (ret)
 		goto out_put_mm;
@@ -1246,14 +1242,13 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 				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))