proc: task_state: deuglify the max_fds calculation

1. The usage of fdt looks very ugly, it can't be NULL if ->files is
   not NULL. We can use "unsigned int max_fds" instead.

2. This also allows to move seq_printf(max_fds) outside of task_lock()
   and join it with the previous seq_printf(). See also the next patch.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Cc: Sterling Alexander <stalexan@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roland McGrath <roland@hack.frob.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 12 deletions

diff --git a/fs/proc/array.c b/fs/proc/array.c
index b5810c228c10..7c8d9aecb070 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -157,9 +157,9 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
         struct user_namespace *user_ns = seq_user_ns(m);
         struct group_info *group_info;
         int g;
-        struct fdtable *fdt = NULL;
         const struct cred *cred;
         pid_t ppid, tpid;
+        unsigned int max_fds = 0;
 
         rcu_read_lock();
         ppid = pid_alive(p) ?
@@ -171,6 +171,12 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
                         tpid = task_pid_nr_ns(tracer, ns);
         }
         cred = get_task_cred(p);
+
+        task_lock(p);
+        if (p->files)
+                max_fds = files_fdtable(p->files)->max_fds;
+        task_unlock(p);
+
         seq_printf(m,
                 "State:\t%s\n"
                 "Tgid:\t%d\n"
@@ -179,7 +185,8 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
                 "PPid:\t%d\n"
                 "TracerPid:\t%d\n"
                 "Uid:\t%d\t%d\t%d\t%d\n"
-                "Gid:\t%d\t%d\t%d\t%d\n",
+                "Gid:\t%d\t%d\t%d\t%d\n"
+                "FDSize:\t%d\nGroups:\t",
                 get_task_state(p),
                 task_tgid_nr_ns(p, ns),
                 task_numa_group_id(p),
@@ -192,16 +199,8 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
                 from_kgid_munged(user_ns, cred->gid),
                 from_kgid_munged(user_ns, cred->egid),
                 from_kgid_munged(user_ns, cred->sgid),
-                from_kgid_munged(user_ns, cred->fsgid));
-
-        task_lock(p);
-        if (p->files)
-                fdt = files_fdtable(p->files);
-        seq_printf(m,
-                "FDSize:\t%d\n"
-                "Groups:\t",
-                fdt ? fdt->max_fds : 0);
-        task_unlock(p);
+                from_kgid_munged(user_ns, cred->fsgid),
+                max_fds);
         rcu_read_unlock();
 
         group_info = cred->group_info;