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>

diff --git a/fs/proc/array.c b/fs/proc/array.c
index b5810c228c104c4cbf7e2c91a1a04973d2cfb68c..7c8d9aecb070a311652984ed185dad14a4adc349 100644 (file)
--- 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;