From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752771AbdKTUaM (ORCPT ); Mon, 20 Nov 2017 15:30:12 -0500 Received: from mail-wm0-f67.google.com ([74.125.82.67]:37521 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752552AbdKTUaJ (ORCPT ); Mon, 20 Nov 2017 15:30:09 -0500 X-Google-Smtp-Source: AGs4zMYVjPm7MPsvdZnH7JdvGXBgdL2LnG0kXCLQgqCc4yH+Y6PbH8H+4Pq0HRdW0x9E3rrQccbtRw== Date: Mon, 20 Nov 2017 23:30:05 +0300 From: Alexey Dobriyan To: akpm@linux-foundation.org Cc: viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org Subject: [PATCH] proc: use %u for pid printing and slightly less stack Message-ID: <20171120203005.GA27743@avx2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Alexey Dobriyan --- 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(-) --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3019,11 +3019,11 @@ 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) { @@ -3035,7 +3035,7 @@ 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; @@ -3047,7 +3047,7 @@ 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); @@ -3226,14 +3226,14 @@ 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)) { @@ -3561,10 +3561,10 @@ 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 --- a/fs/proc/fd.c +++ b/fs/proc/fd.c @@ -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)) --- a/fs/proc/self.c +++ b/fs/proc/self.c @@ -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; } --- a/fs/proc/thread_self.c +++ b/fs/proc/thread_self.c @@ -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; }