Merge branch 'for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

Pull workqueue updates from Tejun Heo:

 - make kworkers report the workqueue it is executing or has executed
   most recently in /proc/PID/comm (so they show up in ps/top)

 - CONFIG_SMP shuffle to move stuff which isn't necessary for UP builds
   inside CONFIG_SMP.

* 'for-4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: move function definitions within CONFIG_SMP block
  workqueue: Make sure struct worker is accessible for wq_worker_comm()
  workqueue: Show the latest workqueue name in /proc/PID/{comm,stat,status}
  proc: Consolidate task->comm formatting into proc_task_name()
  workqueue: Set worker->desc to workqueue name by default
  workqueue: Make worker_attach/detach_pool() update worker->pool
  workqueue: Replace pool->attach_mutex with global wq_pool_attach_mutex

3 files changed, 24 insertions, 16 deletions

diff --git a/fs/proc/array.c b/fs/proc/array.c
index e6d7f41b6684..004077f1a7bf 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -96,22 +96,29 @@
 #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;
-        char tcomm[sizeof(p->comm)];
+        char tcomm[64];
         int ret;
 
-        get_task_comm(tcomm, p);
-
-        seq_puts(m, "Name:\t");
+        if (p->flags & PF_WQ_WORKER)
+                wq_worker_comm(tcomm, sizeof(tcomm), p);
+        else
+                __get_task_comm(tcomm, sizeof(tcomm), p);
 
         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);
 }
 
 /*
@@ -390,7 +397,10 @@ 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) {
@@ -425,7 +435,6 @@ 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);
@@ -452,8 +461,6 @@ 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;
@@ -520,7 +527,7 @@ 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 33ed1746927a..af128b374143 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1563,9 +1563,8 @@ 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 43c70c9e6b62..93eb1906c28d 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -136,6 +136,8 @@ 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 *,