proc: Consolidate task->comm formatting into proc_task_name()

proc shows task->comm in three places - comm, stat, status - and each
is fetching and formatting task->comm slighly differently.  This patch
renames task_name() to proc_task_name(), makes it more generic, and
updates all three paths to use it.

This will enable expanding comm reporting for workqueue workers.

Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/fs/proc/array.c b/fs/proc/array.c
index ae2c807..f29221e 100644 (file)
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -95,7 +95,7 @@
 #include <asm/processor.h>
 #include "internal.h"
 
-static inline void task_name(struct seq_file *m, struct task_struct *p)
+void proc_task_name(struct seq_file *m, struct task_struct *p, bool escape)
 {
        char *buf;
        size_t size;
@@ -104,13 +104,17 @@ static inline void task_name(struct seq_file *m, struct task_struct *p)
 
        get_task_comm(tcomm, p);
 
-       seq_puts(m, "Name:\t");
-
        size = seq_get_buf(m, &buf);
-       ret = string_escape_str(tcomm, buf, size, ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
-       seq_commit(m, ret < size ? ret : -1);
+       if (escape) {
+               ret = string_escape_str(tcomm, buf, size,
+                                       ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
+               if (ret >= size)
+                       ret = -1;
+       } else {
+               ret = strscpy(buf, tcomm, size);
+       }
 
-       seq_putc(m, '\n');
+       seq_commit(m, ret);
 }
 
 /*
@@ -365,7 +369,10 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
 {
        struct mm_struct *mm = get_task_mm(task);
 
-       task_name(m, task);
+       seq_puts(m, "Name:\t");
+       proc_task_name(m, task, true);
+       seq_putc(m, '\n');
+
        task_state(m, ns, pid, task);
 
        if (mm) {
@@ -400,7 +407,6 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
        u64 cutime, cstime, utime, stime;
        u64 cgtime, gtime;
        unsigned long rsslim = 0;
-       char tcomm[sizeof(task->comm)];
        unsigned long flags;
 
        state = *get_task_state(task);
@@ -427,8 +433,6 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
                }
        }
 
-       get_task_comm(tcomm, task);
-
        sigemptyset(&sigign);
        sigemptyset(&sigcatch);
        cutime = cstime = utime = stime = 0;
@@ -495,7 +499,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 
        seq_put_decimal_ull(m, "", pid_nr_ns(pid, ns));
        seq_puts(m, " (");
-       seq_puts(m, tcomm);
+       proc_task_name(m, task, false);
        seq_puts(m, ") ");
        seq_putc(m, state);
        seq_put_decimal_ll(m, " ", ppid);

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1b2ede6..bb192a6 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1565,9 +1565,8 @@ static int comm_show(struct seq_file *m, void *v)
        if (!p)
                return -ESRCH;
 
-       task_lock(p);
-       seq_printf(m, "%s\n", p->comm);
-       task_unlock(p);
+       proc_task_name(m, p, false);
+       seq_putc(m, '\n');
 
        put_task_struct(p);
 

diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 0f1692e..b823fac 100644 (file)
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -131,6 +131,8 @@ unsigned name_to_int(const struct qstr *qstr);
  */
 extern const struct file_operations proc_tid_children_operations;
 
+extern void proc_task_name(struct seq_file *m, struct task_struct *p,
+                          bool escape);
 extern int proc_tid_stat(struct seq_file *, struct pid_namespace *,
                         struct pid *, struct task_struct *);
 extern int proc_tgid_stat(struct seq_file *, struct pid_namespace *,