Some locking cleanups

git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@1373 d57e44dd-8a1f-0410-8b47-8ef2f437770f

qla2x00t/qla2x00-target/qla2x00t.c

@@ -793,7 +793,7 @@ static inline int test_tgt_sess_count(struct q2t_tgt *tgt)
 	return res;
 }
 
-/* Must be called under tgt_host_action_mutex */
+/* Must be called under tgt_host_action_mutex or q2t_unreg_rwsem write locked */
 static void q2t_target_stop(struct scst_tgt *scst_tgt)
 {
 	struct q2t_tgt *tgt = (struct q2t_tgt *)scst_tgt_get_tgt_priv(scst_tgt);
@@ -859,7 +859,7 @@ static void q2t_target_stop(struct scst_tgt *scst_tgt)
 	return;
 }
 
-/* Must be called under tgt_host_action_mutex */
+/* Must be called under tgt_host_action_mutex or q2t_unreg_rwsem write locked */
 static int q2t_target_release(struct scst_tgt *scst_tgt)
 {
 	struct q2t_tgt *tgt = (struct q2t_tgt *)scst_tgt_get_tgt_priv(scst_tgt);

scst/include/scst.h

@@ -1063,10 +1063,7 @@ struct scst_dev_type {
 	/* Optional sysfs attributes */
 	const struct attribute **devt_attrs;
 
-	/*
-	 * Optional sysfs device attributes. They are serialized
-	 * by dev_sysfs_mutex.
-	 */
+	/* Optional sysfs device attributes */
 	const struct attribute **dev_attrs;
 #endif
 
@@ -1817,9 +1814,6 @@ struct scst_device {
 	 */
 	struct rw_semaphore dev_attr_rwsem;
 
-	/* Used to serialize all the device sysfs calls */
-	struct mutex dev_sysfs_mutex;
-
 	struct kobject dev_kobj; /* kobject for this struct */
 	struct kobject *dev_exp_kobj; /* exported groups */
 

scst/src/dev_handlers/scst_vdisk.c

@@ -219,6 +219,8 @@ struct scst_vdisk_dev {
 	struct scst_device *dev;
 	struct list_head vdisk_dev_list_entry;
 
+	struct mutex vdev_sysfs_mutex;
+
 	const struct vdev_type *vdt;
 };
 
@@ -2956,28 +2958,28 @@ static int vdisk_resync_size(struct scst_vdisk_dev *virt_dev)
 	loff_t file_size;
 	int res = 0;
 
-	/*
-	 * There's no need in any lock here, because SCST core serializes
-	 * all device sysfs calls.
-	 */
+	if (mutex_lock_interruptible(&virt_dev->vdev_sysfs_mutex) != 0) {
+		res = -EINTR;
+		goto out;
+	}
 
 	if (!virt_dev->nullio) {
 		res = vdisk_get_file_size(virt_dev->file_name,
 				virt_dev->blockio, &file_size);
 		if (res != 0)
-			goto out;
+			goto out_unlock;
 	} else
 		file_size = VDISK_NULLIO_SIZE;
 
 	if (file_size == virt_dev->file_size) {
 		PRINT_INFO("Size of virtual disk %s remained the same",
 			virt_dev->name);
-		goto out;
+		goto out_unlock;
 	}
 
 	res = scst_suspend_activity(true);
 	if (res != 0)
-		goto out;
+		goto out_unlock;
 
 	virt_dev->file_size = file_size;
 	virt_dev->nblocks = virt_dev->file_size >> virt_dev->block_shift;
@@ -2997,6 +2999,9 @@ static int vdisk_resync_size(struct scst_vdisk_dev *virt_dev)
 
 	scst_resume_activity();
 
+out_unlock:
+	mutex_unlock(&virt_dev->vdev_sysfs_mutex);
+
 out:
 	return res;
 }
@@ -3005,6 +3010,7 @@ static void vdev_init(struct vdev_type *vdt, struct scst_vdisk_dev *virt_dev)
 {
 	memset(virt_dev, 0, sizeof(*virt_dev));
 	spin_lock_init(&virt_dev->flags_lock);
+	mutex_init(&virt_dev->vdev_sysfs_mutex);
 	virt_dev->vdt = vdt;
 
 	virt_dev->block_size = DEF_DISK_BLOCKSIZE;
@@ -3451,11 +3457,6 @@ static int vcdrom_change(struct scst_vdisk_dev *virt_dev,
 
 	TRACE_ENTRY();
 
-	/*
-	 * There's no need in any lock here, because SCST core serializes
-	 * all device sysfs calls.
-	 */
-
 	i_buf = kmalloc(length+1, GFP_KERNEL);
 	if (i_buf == NULL) {
 		PRINT_ERROR("Unable to alloc intermediate buffer with size %d",
@@ -3479,9 +3480,14 @@ static int vcdrom_change(struct scst_vdisk_dev *virt_dev,
 	}
 	*pp = '\0';
 
+	if (mutex_lock_interruptible(&virt_dev->vdev_sysfs_mutex) != 0) {
+		res = -EINTR;
+		goto out_free;
+	}
+
 	res = scst_suspend_activity(true);
 	if (res != 0)
-		goto out;
+		goto out_sysfs_unlock;
 
 	/* To sync with detach*() functions */
 	mutex_lock(&scst_mutex);
@@ -3515,7 +3521,7 @@ static int vcdrom_change(struct scst_vdisk_dev *virt_dev,
 		res = vdisk_get_file_size(virt_dev->file_name,
 				virt_dev->blockio, &err);
 		if (res != 0)
-			goto out_free;
+			goto out_free_fn;
 	} else {
 		err = 0;
 		virt_dev->file_name = NULL;
@@ -3525,7 +3531,7 @@ static int vcdrom_change(struct scst_vdisk_dev *virt_dev,
 		PRINT_ERROR("Prevent medium removal for "
 			"virtual device with name %s", virt_dev->name);
 		res = -EINVAL;
-		goto out_free;
+		goto out_free_fn;
 	}
 
 	virt_dev->file_size = err;
@@ -3556,11 +3562,17 @@ static int vcdrom_change(struct scst_vdisk_dev *virt_dev,
 out_resume:
 	scst_resume_activity();
 
+out_sysfs_unlock:
+	mutex_unlock(&virt_dev->vdev_sysfs_mutex);
+
+out_free:
+	kfree(i_buf);
+
 out:
 	TRACE_EXIT_RES(res);
 	return res;
 
-out_free:
+out_free_fn:
 	kfree(virt_dev->file_name);
 	virt_dev->file_name = old_fn;
 
@@ -3721,8 +3733,16 @@ static ssize_t vdisk_sysfs_size_show(struct kobject *kobj,
 	dev = container_of(kobj, struct scst_device, dev_kobj);
 	virt_dev = (struct scst_vdisk_dev *)dev->dh_priv;
 
+	if (mutex_lock_interruptible(&virt_dev->vdev_sysfs_mutex) != 0) {
+		pos = -EINTR;
+		goto out;
+	}
+
 	pos = sprintf(buf, "%lld\n", virt_dev->file_size);
 
+	mutex_unlock(&virt_dev->vdev_sysfs_mutex);
+
+out:
 	TRACE_EXIT_RES(pos);
 	return pos;
 }
@@ -3847,8 +3867,16 @@ static ssize_t vdisk_sysfs_filename_show(struct kobject *kobj,
 	dev = container_of(kobj, struct scst_device, dev_kobj);
 	virt_dev = (struct scst_vdisk_dev *)dev->dh_priv;
 
+	if (mutex_lock_interruptible(&virt_dev->vdev_sysfs_mutex) != 0) {
+		pos = -EINTR;
+		goto out;
+	}
+
 	pos = sprintf(buf, "%s\n", virt_dev->file_name);
 
+	mutex_unlock(&virt_dev->vdev_sysfs_mutex);
+
+out:
 	TRACE_EXIT_RES(pos);
 	return pos;
 }

scst/src/scst_sysfs.c

@@ -654,17 +654,10 @@ static ssize_t scst_dev_attr_show(struct kobject *kobj, struct attribute *attr,
 		goto out;
 	}
 
-	if (mutex_lock_interruptible(&dev->dev_sysfs_mutex) != 0) {
-		res = -EINTR;
-		goto out;
-	}
-
 	kobj_attr = container_of(attr, struct kobj_attribute, attr);
 
 	res = kobj_attr->show(kobj, kobj_attr, buf);
 
-	mutex_unlock(&dev->dev_sysfs_mutex);
-
 	up_read(&dev->dev_attr_rwsem);
 
 out:
@@ -685,17 +678,10 @@ static ssize_t scst_dev_attr_store(struct kobject *kobj, struct attribute *attr,
 		goto out;
 	}
 
-	if (mutex_lock_interruptible(&dev->dev_sysfs_mutex) != 0) {
-		res = -EINTR;
-		goto out;
-	}
-
 	kobj_attr = container_of(attr, struct kobj_attribute, attr);
 
 	res = kobj_attr->store(kobj, kobj_attr, buf, count);
 
-	mutex_unlock(&dev->dev_sysfs_mutex);
-
 	up_read(&dev->dev_attr_rwsem);
 
 out:
@@ -720,7 +706,6 @@ int scst_create_device_sysfs(struct scst_device *dev)
 	TRACE_ENTRY();
 
 	init_rwsem(&dev->dev_attr_rwsem);
-	mutex_init(&dev->dev_sysfs_mutex);
 
 	dev->dev_kobj_initialized = 1;