staging: lustre: obdclass: bug fixes for lu_device_type handling

There was no protection when inc/dec lu_device_type::ldt_device_nr,
which may caused the ldt_device_nr to be wrong and trigger assert.
This patch redefine lu_device_type::ldt_device_nr as atomic type.

There was no protection when add/del lu_device_type::ldt_linkage
into/from the global lu_device_types list, which may caused bad
address accessing. This patch uses the existing obd_types_lock
to protect related operations.

We do NOT need lu_types_stop() any longer. Such function scans
the global lu_device_types list, and for each type item on it
which has zerod lu_device_type::ldt_device_nr, call its stop()
method. In fact, the lu_device_type::ldt_device_nr only will be
zero when the last lu_device_fini() is called, and at that time,
inside the lu_device_fini(), its stop() method will be called.
So it is unnecessary to call the stop() again via lu_types_stop().

Signed-off-by: Fan Yong <fan.yong@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-4604
Reviewed-on: http://review.whamcloud.com/8694
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/lustre/lustre/include/lu_object.h b/drivers/staging/lustre/lustre/include/lu_object.h
index 6e25c1bb6aa316aa7e783ed9c1e9fc45aeec48b5..25c12d8d120a5b1d9d725bcb44b9c08cda802f20 100644 (file)
--- a/drivers/staging/lustre/lustre/include/lu_object.h
+++ b/drivers/staging/lustre/lustre/include/lu_object.h
@@ -327,7 +327,7 @@ struct lu_device_type {
        /**
         * Number of existing device type instances.
         */
-       unsigned                                ldt_device_nr;
+       atomic_t                                ldt_device_nr;
        /**
         * Linkage into a global list of all device types.
         *
@@ -673,7 +673,6 @@ void lu_object_add(struct lu_object *before, struct lu_object *o);
 
 int  lu_device_type_init(struct lu_device_type *ldt);
 void lu_device_type_fini(struct lu_device_type *ldt);
-void lu_types_stop(void);
 
 /** @} ctors */
 

diff --git a/drivers/staging/lustre/lustre/llite/vvp_dev.c b/drivers/staging/lustre/lustre/llite/vvp_dev.c
index e623216e962dd2a5035928013904a455894168f9..771c0bd190a535e2af4040f382672878fc5b879b 100644 (file)
--- a/drivers/staging/lustre/lustre/llite/vvp_dev.c
+++ b/drivers/staging/lustre/lustre/llite/vvp_dev.c
@@ -368,12 +368,6 @@ int cl_sb_fini(struct super_block *sb)
                CERROR("Cannot cleanup cl-stack due to memory shortage.\n");
                result = PTR_ERR(env);
        }
-       /*
-        * If mount failed (sbi->ll_cl == NULL), and this there are no other
-        * mounts, stop device types manually (this usually happens
-        * automatically when last device is destroyed).
-        */
-       lu_types_stop();
        return result;
 }
 

diff --git a/drivers/staging/lustre/lustre/obdclass/lu_object.c b/drivers/staging/lustre/lustre/obdclass/lu_object.c
index 9b03059f34d63f585232ed4e55e4ab1964b0ed82..0c00bf81b8961aa1a0dc8d3c25fa5dce610530fa 100644 (file)
--- a/drivers/staging/lustre/lustre/obdclass/lu_object.c
+++ b/drivers/staging/lustre/lustre/obdclass/lu_object.c
@@ -726,34 +726,31 @@ int lu_device_type_init(struct lu_device_type *ldt)
 {
        int result = 0;
 
+       atomic_set(&ldt->ldt_device_nr, 0);
        INIT_LIST_HEAD(&ldt->ldt_linkage);
        if (ldt->ldt_ops->ldto_init)
                result = ldt->ldt_ops->ldto_init(ldt);
-       if (result == 0)
+
+       if (!result) {
+               spin_lock(&obd_types_lock);
                list_add(&ldt->ldt_linkage, &lu_device_types);
+               spin_unlock(&obd_types_lock);
+       }
+
        return result;
 }
 EXPORT_SYMBOL(lu_device_type_init);
 
 void lu_device_type_fini(struct lu_device_type *ldt)
 {
+       spin_lock(&obd_types_lock);
        list_del_init(&ldt->ldt_linkage);
+       spin_unlock(&obd_types_lock);
        if (ldt->ldt_ops->ldto_fini)
                ldt->ldt_ops->ldto_fini(ldt);
 }
 EXPORT_SYMBOL(lu_device_type_fini);
 
-void lu_types_stop(void)
-{
-       struct lu_device_type *ldt;
-
-       list_for_each_entry(ldt, &lu_device_types, ldt_linkage) {
-               if (ldt->ldt_device_nr == 0 && ldt->ldt_ops->ldto_stop)
-                       ldt->ldt_ops->ldto_stop(ldt);
-       }
-}
-EXPORT_SYMBOL(lu_types_stop);
-
 /**
  * Global list of all sites on this node
  */
@@ -1082,8 +1079,10 @@ EXPORT_SYMBOL(lu_device_put);
  */
 int lu_device_init(struct lu_device *d, struct lu_device_type *t)
 {
-       if (t->ldt_device_nr++ == 0 && t->ldt_ops->ldto_start)
+       if (atomic_inc_return(&t->ldt_device_nr) == 1 &&
+           t->ldt_ops->ldto_start)
                t->ldt_ops->ldto_start(t);
+
        memset(d, 0, sizeof(*d));
        atomic_set(&d->ld_ref, 0);
        d->ld_type = t;
@@ -1098,9 +1097,8 @@ EXPORT_SYMBOL(lu_device_init);
  */
 void lu_device_fini(struct lu_device *d)
 {
-       struct lu_device_type *t;
+       struct lu_device_type *t = d->ld_type;
 
-       t = d->ld_type;
        if (d->ld_obd) {
                d->ld_obd->obd_lu_dev = NULL;
                d->ld_obd = NULL;
@@ -1109,8 +1107,10 @@ void lu_device_fini(struct lu_device *d)
        lu_ref_fini(&d->ld_reference);
        LASSERTF(atomic_read(&d->ld_ref) == 0,
                 "Refcount is %u\n", atomic_read(&d->ld_ref));
-       LASSERT(t->ldt_device_nr > 0);
-       if (--t->ldt_device_nr == 0 && t->ldt_ops->ldto_stop)
+       LASSERT(atomic_read(&t->ldt_device_nr) > 0);
+
+       if (atomic_dec_and_test(&t->ldt_device_nr) &&
+           t->ldt_ops->ldto_stop)
                t->ldt_ops->ldto_stop(t);
 }
 EXPORT_SYMBOL(lu_device_fini);

diff --git a/drivers/staging/lustre/lustre/obdclass/obd_mount.c b/drivers/staging/lustre/lustre/obdclass/obd_mount.c
index 4931e37adedebbf1a63a74a7c792d49c8ca5722d..33d6c423c6fbe1363dbc235a5da1efe92195b96e 100644 (file)
--- a/drivers/staging/lustre/lustre/obdclass/obd_mount.c
+++ b/drivers/staging/lustre/lustre/obdclass/obd_mount.c
@@ -670,7 +670,6 @@ int lustre_common_put_super(struct super_block *sb)
        }
        /* Drop a ref to the mounted disk */
        lustre_put_lsi(sb);
-       lu_types_stop();
        return rc;
 }
 EXPORT_SYMBOL(lustre_common_put_super);