scsi_dh: get module reference outside of device handler

We need to grab a reference to the module before calling the attach
routines to avoid a small race vs module removal.  It also cleans up
the code significantly as a side effect.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>
This commit is contained in:
Christoph Hellwig 2014-09-13 19:41:16 -07:00
parent 0b9c08442c
commit 27c888f0bb
5 changed files with 22 additions and 25 deletions

View File

@ -102,23 +102,36 @@ static int scsi_dh_handler_attach(struct scsi_device *sdev,
if (sdev->scsi_dh_data) {
if (sdev->scsi_dh_data->scsi_dh != scsi_dh)
err = -EBUSY;
else
kref_get(&sdev->scsi_dh_data->kref);
} else if (scsi_dh->attach) {
return -EBUSY;
kref_get(&sdev->scsi_dh_data->kref);
return 0;
}
if (scsi_dh->attach) {
if (!try_module_get(scsi_dh->module))
return -EINVAL;
err = scsi_dh->attach(sdev);
if (!err) {
kref_init(&sdev->scsi_dh_data->kref);
sdev->scsi_dh_data->sdev = sdev;
if (err) {
module_put(scsi_dh->module);
return err;
}
kref_init(&sdev->scsi_dh_data->kref);
sdev->scsi_dh_data->sdev = sdev;
}
return err;
}
static void __detach_handler (struct kref *kref)
{
struct scsi_dh_data *scsi_dh_data = container_of(kref, struct scsi_dh_data, kref);
scsi_dh_data->scsi_dh->detach(scsi_dh_data->sdev);
struct scsi_dh_data *scsi_dh_data =
container_of(kref, struct scsi_dh_data, kref);
struct scsi_device_handler *scsi_dh = scsi_dh_data->scsi_dh;
scsi_dh->detach(scsi_dh_data->sdev);
module_put(scsi_dh->module);
}
/*

View File

@ -873,9 +873,6 @@ static int alua_bus_attach(struct scsi_device *sdev)
if ((err != SCSI_DH_OK) && (err != SCSI_DH_DEV_OFFLINED))
goto failed;
if (!try_module_get(THIS_MODULE))
goto failed;
spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
sdev->scsi_dh_data = scsi_dh_data;
spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
@ -908,7 +905,6 @@ static void alua_bus_detach(struct scsi_device *sdev)
if (h->buff && h->inq != h->buff)
kfree(h->buff);
kfree(scsi_dh_data);
module_put(THIS_MODULE);
sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", ALUA_DH_NAME);
}

View File

@ -692,9 +692,6 @@ static int clariion_bus_attach(struct scsi_device *sdev)
if (err != SCSI_DH_OK)
goto failed;
if (!try_module_get(THIS_MODULE))
goto failed;
spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
sdev->scsi_dh_data = scsi_dh_data;
spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
@ -728,7 +725,6 @@ static void clariion_bus_detach(struct scsi_device *sdev)
CLARIION_NAME);
kfree(scsi_dh_data);
module_put(THIS_MODULE);
}
static int __init clariion_init(void)

View File

@ -377,9 +377,6 @@ static int hp_sw_bus_attach(struct scsi_device *sdev)
if (ret != SCSI_DH_OK || h->path_state == HP_SW_PATH_UNINITIALIZED)
goto failed;
if (!try_module_get(THIS_MODULE))
goto failed;
spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
sdev->scsi_dh_data = scsi_dh_data;
spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
@ -406,7 +403,6 @@ static void hp_sw_bus_detach( struct scsi_device *sdev )
scsi_dh_data = sdev->scsi_dh_data;
sdev->scsi_dh_data = NULL;
spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
module_put(THIS_MODULE);
sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", HP_SW_NAME);

View File

@ -878,9 +878,6 @@ static int rdac_bus_attach(struct scsi_device *sdev)
if (err != SCSI_DH_OK)
goto clean_ctlr;
if (!try_module_get(THIS_MODULE))
goto clean_ctlr;
spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
sdev->scsi_dh_data = scsi_dh_data;
spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
@ -924,7 +921,6 @@ static void rdac_bus_detach( struct scsi_device *sdev )
kref_put(&h->ctlr->kref, release_controller);
spin_unlock(&list_lock);
kfree(scsi_dh_data);
module_put(THIS_MODULE);
sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", RDAC_NAME);
}