proc: convert /proc/$PID/cmdline to seq_file interface

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 4 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index f5d0f8f39a57..a6d0214c7c95 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -200,9 +200,16 @@ static int proc_root_link(struct dentry *dentry, struct path *path)
         return result;
 }
 
-static int proc_pid_cmdline(struct task_struct *task, char *buffer)
+static int proc_pid_cmdline(struct seq_file *m, struct pid_namespace *ns,
+                            struct pid *pid, struct task_struct *task)
 {
-        return get_cmdline(task, buffer, PAGE_SIZE);
+        /*
+         * Rely on struct seq_operations::show() being called once
+         * per internal buffer allocation. See single_open(), traverse().
+         */
+        BUG_ON(m->size < PAGE_SIZE);
+        m->count += get_cmdline(task, m->buf, PAGE_SIZE);
+        return 0;
 }
 
 static int proc_pid_auxv(struct seq_file *m, struct pid_namespace *ns,
@@ -2567,7 +2574,7 @@ static const struct pid_entry tgid_base_stuff[] = {
 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
         ONE("syscall",    S_IRUSR, proc_pid_syscall),
 #endif
-        INF("cmdline",    S_IRUGO, proc_pid_cmdline),
+        ONE("cmdline",    S_IRUGO, proc_pid_cmdline),
         ONE("stat",       S_IRUGO, proc_tgid_stat),
         ONE("statm",      S_IRUGO, proc_pid_statm),
         REG("maps",       S_IRUGO, proc_pid_maps_operations),
@@ -2903,7 +2910,7 @@ static const struct pid_entry tid_base_stuff[] = {
 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
         ONE("syscall",   S_IRUSR, proc_pid_syscall),
 #endif
-        INF("cmdline",   S_IRUGO, proc_pid_cmdline),
+        ONE("cmdline",   S_IRUGO, proc_pid_cmdline),
         ONE("stat",      S_IRUGO, proc_tid_stat),
         ONE("statm",     S_IRUGO, proc_pid_statm),
         REG("maps",      S_IRUGO, proc_tid_maps_operations),