From 7205981e045e752ccf96cf6ddd703a98c59d4339 Mon Sep 17 00:00:00 2001 From: Tyrel Datwyler Date: Wed, 20 Mar 2019 13:41:50 -0500 Subject: [PATCH] scsi: ibmvscsi: Protect ibmvscsi_head from concurrent modificaiton For each ibmvscsi host created during a probe or destroyed during a remove we either add or remove that host to/from the global ibmvscsi_head list. This runs the risk of concurrent modification. This patch adds a simple spinlock around the list modification calls to prevent concurrent updates as is done similarly in the ibmvfc driver and ipr driver. Fixes: 32d6e4b6e4ea ("scsi: ibmvscsi: add vscsi hosts to global list_head") Cc: # v4.10+ Signed-off-by: Tyrel Datwyler Signed-off-by: Martin K. Petersen --- drivers/scsi/ibmvscsi/ibmvscsi.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c index 1135e74646e2..2b22969f3f63 100644 --- a/drivers/scsi/ibmvscsi/ibmvscsi.c +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c @@ -96,6 +96,7 @@ static int client_reserve = 1; static char partition_name[96] = "UNKNOWN"; static unsigned int partition_number = -1; static LIST_HEAD(ibmvscsi_head); +static DEFINE_SPINLOCK(ibmvscsi_driver_lock); static struct scsi_transport_template *ibmvscsi_transport_template; @@ -2270,7 +2271,9 @@ static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id) } dev_set_drvdata(&vdev->dev, hostdata); + spin_lock(&ibmvscsi_driver_lock); list_add_tail(&hostdata->host_list, &ibmvscsi_head); + spin_unlock(&ibmvscsi_driver_lock); return 0; add_srp_port_failed: @@ -2292,7 +2295,9 @@ static int ibmvscsi_probe(struct vio_dev *vdev, const struct vio_device_id *id) static int ibmvscsi_remove(struct vio_dev *vdev) { struct ibmvscsi_host_data *hostdata = dev_get_drvdata(&vdev->dev); + spin_lock(&ibmvscsi_driver_lock); list_del(&hostdata->host_list); + spin_unlock(&ibmvscsi_driver_lock); unmap_persist_bufs(hostdata); release_event_pool(&hostdata->pool, hostdata); ibmvscsi_release_crq_queue(&hostdata->queue, hostdata,