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Date: Sun, 19 Oct 2014 17:59:59 +0200
From: Christoph Hellwig <hch@....de>
To: Chandra Seetharaman <sekharan@...ibm.com>,
Hannes Reinecke <hare@...e.de>,
Mike Christie <michaelc@...wisc.edu>
Cc: Sean Stewart <Sean.Stewart@...app.com>,
Bart Van Assche <bvanassche@....org>,
linux-kernel@...r.kernel.org
Subject: [PATCH 1/6] 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@....de>
---
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 33e422e..1a8dbf3 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 e99507e..45b1795 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -866,9 +866,6 @@ 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);
@@ -901,7 +898,6 @@ 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 8476538..153b4c3 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 4ee2759..367e6f5 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 1b5bc92..b850954 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);
}
--
1.9.1
--
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