[PATCH V3 2/3] scsi: core: fix failure handling of scsi_add_host_with_dma

[Ming Lei <ming.lei@redhat.com>]

When scsi_add_host_with_dma() return failure, the caller will call
scsi_host_put(shost) to release everything allocated for this host
instance. So we can't free allocated stuff in scsi_add_host_with_dma(),
otherwise double free will be caused.

Strictly speaking, these host resources allocation should have been
moved to scsi_host_alloc(), but the allocation may need driver's
info which can be built between calling scsi_host_alloc() and
scsi_add_host(), so just keep the allocations in
scsi_add_host_with_dma().

Fixes the problem by relying on host device's release handler to
release everything.

Cc: Bart Van Assche <bvanassche@acm.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 drivers/scsi/hosts.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index ada11e3ae577..6cbc3eb16525 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -279,23 +279,22 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 
 		if (!shost->work_q) {
 			error = -EINVAL;
-			goto out_free_shost_data;
+			goto out_del_dev;
 		}
 	}
 
 	error = scsi_sysfs_add_host(shost);
 	if (error)
-		goto out_destroy_host;
+		goto out_del_dev;
 
 	scsi_proc_host_add(shost);
 	scsi_autopm_put_host(shost);
 	return error;
 
- out_destroy_host:
-	if (shost->work_q)
-		destroy_workqueue(shost->work_q);
- out_free_shost_data:
-	kfree(shost->shost_data);
+	/*
+	 * any host allocation in this function will be freed in
+	 * scsi_host_dev_release, so don't free them in the failure path
+	 */
  out_del_dev:
 	device_del(&shost->shost_dev);
  out_del_gendev:
@@ -305,7 +304,6 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 	pm_runtime_disable(&shost->shost_gendev);
 	pm_runtime_set_suspended(&shost->shost_gendev);
 	pm_runtime_put_noidle(&shost->shost_gendev);
-	scsi_mq_destroy_tags(shost);
  fail:
 	return error;
 }
-- 
2.29.2