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Subject[PATCH 5/6] proc: Consolidate task->comm formatting into proc_task_name()
Date
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>
---
fs/proc/array.c | 26 +++++++++++++++-----------
fs/proc/base.c | 5 ++---
fs/proc/internal.h | 2 ++
3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/fs/proc/array.c b/fs/proc/array.c
index ae2c807..f29221e 100644
--- 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 2eee4d7..eb17917ca 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1581,9 +1581,8 @@ 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..b823fac62 100644
--- 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 *,
--
2.9.5
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