From 27c888f0bb889693c6a3b6d39eba3265c16c072f Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sat, 13 Sep 2014 19:41:16 -0700 Subject: [PATCH] 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 Reviewed-by: Mike Christie Reviewed-by: Hannes Reinecke --- drivers/scsi/device_handler/scsi_dh.c | 31 +++++++++++++++------ drivers/scsi/device_handler/scsi_dh_alua.c | 4 --- drivers/scsi/device_handler/scsi_dh_emc.c | 4 --- drivers/scsi/device_handler/scsi_dh_hp_sw.c | 4 --- drivers/scsi/device_handler/scsi_dh_rdac.c | 4 --- 5 files changed, 22 insertions(+), 25 deletions(-) diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c index 33e422e75835..1a8dbf33f2ac 100644 --- a/drivers/scsi/device_handler/scsi_dh.c +++ b/drivers/scsi/device_handler/scsi_dh.c @@ -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); } /* diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index fd78bdc53528..9115c31f26e9 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -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); } diff --git a/drivers/scsi/device_handler/scsi_dh_emc.c b/drivers/scsi/device_handler/scsi_dh_emc.c index 84765384c47c..153b4c3547a2 100644 --- a/drivers/scsi/device_handler/scsi_dh_emc.c +++ b/drivers/scsi/device_handler/scsi_dh_emc.c @@ -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) diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c index 4824bfbe3051..cf36557a1d4d 100644 --- a/drivers/scsi/device_handler/scsi_dh_hp_sw.c +++ b/drivers/scsi/device_handler/scsi_dh_hp_sw.c @@ -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); diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c index 1b5bc9293e37..b850954c4e22 100644 --- a/drivers/scsi/device_handler/scsi_dh_rdac.c +++ b/drivers/scsi/device_handler/scsi_dh_rdac.c @@ -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); } -- 2.20.1