gfs2: make gfs2_glock.gl_owner_pid be a struct pid *

The gl_owner_pid field is used to get the lock owning task by its pid, so make
it in a proper manner, i.e.  by using the struct pid pointer and pid_task()
function.

The pid_task() becomes exported for the gfs2 module.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 82471c82f02474346093fdb64ab86a5b299cd057..7175a4d064356f6f36860ea57d24feed1acb3d0e 100644 (file)
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -334,7 +334,7 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
        gl->gl_state = LM_ST_UNLOCKED;
        gl->gl_demote_state = LM_ST_EXCLUSIVE;
        gl->gl_hash = hash;
-       gl->gl_owner_pid = 0;
+       gl->gl_owner_pid = NULL;
        gl->gl_ip = 0;
        gl->gl_ops = glops;
        gl->gl_req_gh = NULL;
@@ -632,7 +632,7 @@ static void gfs2_glmutex_lock(struct gfs2_glock *gl)
                wait_on_holder(&gh);
                gfs2_holder_uninit(&gh);
        } else {
-               gl->gl_owner_pid = current->pid;
+               gl->gl_owner_pid = get_pid(task_pid(current));
                gl->gl_ip = (unsigned long)__builtin_return_address(0);
                spin_unlock(&gl->gl_spin);
        }
@@ -653,7 +653,7 @@ static int gfs2_glmutex_trylock(struct gfs2_glock *gl)
        if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
                acquired = 0;
        } else {
-               gl->gl_owner_pid = current->pid;
+               gl->gl_owner_pid = get_pid(task_pid(current));
                gl->gl_ip = (unsigned long)__builtin_return_address(0);
        }
        spin_unlock(&gl->gl_spin);
@@ -669,12 +669,17 @@ static int gfs2_glmutex_trylock(struct gfs2_glock *gl)
 
 static void gfs2_glmutex_unlock(struct gfs2_glock *gl)
 {
+       struct pid *pid;
+
        spin_lock(&gl->gl_spin);
        clear_bit(GLF_LOCK, &gl->gl_flags);
-       gl->gl_owner_pid = 0;
+       pid = gl->gl_owner_pid;
+       gl->gl_owner_pid = NULL;
        gl->gl_ip = 0;
        run_queue(gl);
        spin_unlock(&gl->gl_spin);
+
+       put_pid(pid);
 }
 
 /**
@@ -1881,13 +1886,13 @@ static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl)
        print_dbg(gi, "  gl_ref = %d\n", atomic_read(&gl->gl_ref));
        print_dbg(gi, "  gl_state = %u\n", gl->gl_state);
        if (gl->gl_owner_pid) {
-               gl_owner = find_task_by_pid(gl->gl_owner_pid);
+               gl_owner = pid_task(gl->gl_owner_pid, PIDTYPE_PID);
                if (gl_owner)
                        print_dbg(gi, "  gl_owner = pid %d (%s)\n",
-                                 gl->gl_owner_pid, gl_owner->comm);
+                                 pid_nr(gl->gl_owner_pid), gl_owner->comm);
                else
                        print_dbg(gi, "  gl_owner = %d (ended)\n",
-                                 gl->gl_owner_pid);
+                                 pid_nr(gl->gl_owner_pid));
        } else
                print_dbg(gi, "  gl_owner = -1\n");
        print_dbg(gi, "  gl_ip = %lu\n", gl->gl_ip);

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 4b724e772602ad0869d7f56a2408b932902a7a42..525dcae352d6b53bae1e2c464c488429c39b69a0 100644 (file)
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -182,7 +182,7 @@ struct gfs2_glock {
        unsigned int gl_hash;
        unsigned int gl_demote_state; /* state requested by remote node */
        unsigned long gl_demote_time; /* time of first demote request */
-       pid_t gl_owner_pid;
+       struct pid *gl_owner_pid;
        unsigned long gl_ip;
        struct list_head gl_holders;
        struct list_head gl_waiters1;   /* HIF_MUTEX */

diff --git a/kernel/pid.c b/kernel/pid.c
index f815455431bff3c95855a674086e6c1d8322a7c4..3b30bccdfcdc92def5dcb4313d4606bc58d6cb46 100644 (file)
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -368,6 +368,7 @@ struct task_struct * fastcall pid_task(struct pid *pid, enum pid_type type)
        }
        return result;
 }
+EXPORT_SYMBOL(pid_task);
 
 /*
  * Must be called under rcu_read_lock() or with tasklist_lock read-held.