linux-kernel - [PATCH 05/15] print_integer, proc: rewrite /proc/thread-self via print

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Date:   Mon, 20 Apr 2020 23:57:33 +0300
From:   Alexey Dobriyan <adobriyan@...il.com>
To:     akpm@...ux-foundation.org
Cc:     adobriyan@...il.com, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, pmladek@...e.com,
        rostedt@...dmis.org, sergey.senozhatsky@...il.com,
        andriy.shevchenko@...ux.intel.com, linux@...musvillemoes.dk
Subject: [PATCH 05/15] print_integer, proc: rewrite /proc/thread-self via print_integer()

Signed-off-by: Alexey Dobriyan <adobriyan@...il.com>
---
 fs/proc/thread_self.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c
index f61ae53533f5..c29d37e3bd28 100644
--- a/fs/proc/thread_self.c
+++ b/fs/proc/thread_self.c
@@ -15,14 +15,20 @@ static const char *proc_thread_self_get_link(struct dentry *dentry,
 	struct pid_namespace *ns = proc_pid_ns(inode);
 	pid_t tgid = task_tgid_nr_ns(current, ns);
 	pid_t pid = task_pid_nr_ns(current, ns);
+	char buf[10 + 6 + 10 + 1];
+	char *p = buf + sizeof(buf);
 	char *name;
 
 	if (!pid)
 		return ERR_PTR(-ENOENT);
-	name = kmalloc(10 + 6 + 10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
+	name = kmalloc(sizeof(buf), dentry ? GFP_KERNEL : GFP_ATOMIC);
 	if (unlikely(!name))
 		return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
-	sprintf(name, "%u/task/%u", tgid, pid);
+	*--p = '\0';
+	p = _print_integer_u32(p, pid);
+	p = memcpy(p - 6, "/task/", 6);
+	p = _print_integer_u32(p, tgid);
+	memcpy(name, p, buf + sizeof(buf) - p);
 	set_delayed_call(done, kfree_link, name);
 	return name;
 }
-- 
2.24.1