Bsg holding a reference to the parent device may result in a crash if a
bsg file handle is closed after the parent device driver has unloaded.
Holding a reference is not really needed: the parent device must exist
between bsg_register_queue and bsg_unregister_queue. Before the device
goes away the caller does blk_cleanup_queue so that all in-flight
requests to the device are gone and all new requests cannot pass beyond
the queue. The queue itself is a refcounted object and it will stay
alive with a bsg file.
Based on analysis, previous patch and changelog from Anatoliy Glagolev.
Reported-by: Anatoliy Glagolev <glagolig@xxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/bsg-lib.c | 6 ++---
block/bsg.c | 39 ++++-------------------------
drivers/scsi/scsi_transport_fc.c | 7 +++---
drivers/scsi/scsi_transport_iscsi.c | 2 +-
drivers/scsi/scsi_transport_sas.c | 19 +++++---------
include/linux/bsg-lib.h | 3 +--
include/linux/bsg.h | 6 +----
7 files changed, 19 insertions(+), 63 deletions(-)
diff --git a/block/bsg-lib.c b/block/bsg-lib.c
index fc2e5ff2c4b9..9419def8c017 100644
--- a/block/bsg-lib.c
+++ b/block/bsg-lib.c
@@ -303,11 +303,9 @@ static void bsg_exit_rq(struct request_queue *q, struct request *req)
* @name: device to give bsg device
* @job_fn: bsg job handler
* @dd_job_size: size of LLD data needed for each job
- * @release: @dev release function
*/
struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
- bsg_job_fn *job_fn, int dd_job_size,
- void (*release)(struct device *))
+ bsg_job_fn *job_fn, int dd_job_size)
{
struct request_queue *q;
int ret;
@@ -331,7 +329,7 @@ struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
blk_queue_softirq_done(q, bsg_softirq_done);
blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
- ret = bsg_register_queue(q, dev, name, &bsg_transport_ops, release);
+ ret = bsg_register_queue(q, dev, name, &bsg_transport_ops);
if (ret) {
printk(KERN_ERR "%s: bsg interface failed to "
"initialize - register queue\n", dev->kobj.name);
diff --git a/block/bsg.c b/block/bsg.c
index 30876c5fbf15..132e657e2d91 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -649,18 +649,6 @@ static struct bsg_device *bsg_alloc_device(void)
return bd;
}
-static void bsg_kref_release_function(struct kref *kref)
-{
- struct bsg_class_device *bcd =
- container_of(kref, struct bsg_class_device, ref);
- struct device *parent = bcd->parent;
-
- if (bcd->release)
- bcd->release(bcd->parent);
-
- put_device(parent);
-}
-
static int bsg_put_device(struct bsg_device *bd)
{
int ret = 0, do_free;
@@ -693,7 +681,6 @@ static int bsg_put_device(struct bsg_device *bd)
kfree(bd);
out:
- kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
if (do_free)
blk_put_queue(q);
return ret;
@@ -759,8 +746,6 @@ static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
*/
mutex_lock(&bsg_mutex);
bcd = idr_find(&bsg_minor_idr, iminor(inode));
- if (bcd)
- kref_get(&bcd->ref);
mutex_unlock(&bsg_mutex);
if (!bcd)
@@ -771,8 +756,6 @@ static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
return bd;
bd = bsg_add_device(inode, bcd->queue, file);
- if (IS_ERR(bd))
- kref_put(&bcd->ref, bsg_kref_release_function);
return bd;
}
@@ -912,25 +895,17 @@ void bsg_unregister_queue(struct request_queue *q)
sysfs_remove_link(&q->kobj, "bsg");
device_unregister(bcd->class_dev);
bcd->class_dev = NULL;
- kref_put(&bcd->ref, bsg_kref_release_function);
mutex_unlock(&bsg_mutex);
}
EXPORT_SYMBOL_GPL(bsg_unregister_queue);
int bsg_register_queue(struct request_queue *q, struct device *parent,
- const char *name, const struct bsg_ops *ops,
- void (*release)(struct device *))
+ const char *name, const struct bsg_ops *ops)
{
struct bsg_class_device *bcd;
dev_t dev;
int ret;
struct device *class_dev = NULL;
- const char *devname;
-
- if (name)
- devname = name;
- else
- devname = dev_name(parent);
/*
* we need a proper transport to send commands, not a stacked device
@@ -954,15 +929,12 @@ int bsg_register_queue(struct request_queue *q, struct device *parent,
bcd->minor = ret;
bcd->queue = q;
- bcd->parent = get_device(parent);
- bcd->release = release;
bcd->ops = ops;
- kref_init(&bcd->ref);
dev = MKDEV(bsg_major, bcd->minor);
- class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname);
+ class_dev = device_create(bsg_class, parent, dev, NULL, "%s", name);
if (IS_ERR(class_dev)) {
ret = PTR_ERR(class_dev);
- goto put_dev;
+ goto idr_remove;
}
bcd->class_dev = class_dev;
@@ -977,8 +949,7 @@ int bsg_register_queue(struct request_queue *q, struct device *parent,
unregister_class_dev:
device_unregister(class_dev);
-put_dev:
- put_device(parent);
+idr_remove:
idr_remove(&bsg_minor_idr, bcd->minor);
unlock:
mutex_unlock(&bsg_mutex);
@@ -992,7 +963,7 @@ int bsg_scsi_register_queue(struct request_queue *q, struct device *parent)
return -EINVAL;
}
- return bsg_register_queue(q, parent, NULL, &bsg_scsi_ops, NULL);
+ return bsg_register_queue(q, parent, dev_name(parent), &bsg_scsi_ops);
}
EXPORT_SYMBOL_GPL(bsg_scsi_register_queue);
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index be3be0f9cb2d..d97f689b9278 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -3781,8 +3781,7 @@ fc_bsg_hostadd(struct Scsi_Host *shost, struct fc_host_attrs *fc_host)
snprintf(bsg_name, sizeof(bsg_name),
"fc_host%d", shost->host_no);
- q = bsg_setup_queue(dev, bsg_name, fc_bsg_dispatch, i->f->dd_bsg_size,
- NULL);
+ q = bsg_setup_queue(dev, bsg_name, fc_bsg_dispatch, i->f->dd_bsg_size);
if (IS_ERR(q)) {
dev_err(dev,
"fc_host%d: bsg interface failed to initialize - setup queue\n",
@@ -3827,8 +3826,8 @@ fc_bsg_rportadd(struct Scsi_Host *shost, struct fc_rport *rport)
if (!i->f->bsg_request)
return -ENOTSUPP;
- q = bsg_setup_queue(dev, NULL, fc_bsg_dispatch, i->f->dd_bsg_size,
- NULL);
+ q = bsg_setup_queue(dev, dev_name(dev), fc_bsg_dispatch,
+ i->f->dd_bsg_size);
if (IS_ERR(q)) {
dev_err(dev, "failed to setup bsg queue\n");
return PTR_ERR(q);
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 65f6c94f2e9b..6fd2fe210fc3 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -1542,7 +1542,7 @@ iscsi_bsg_host_add(struct Scsi_Host *shost, struct iscsi_cls_host *ihost)
return -ENOTSUPP;
snprintf(bsg_name, sizeof(bsg_name), "iscsi_host%d", shost->host_no);
- q = bsg_setup_queue(dev, bsg_name, iscsi_bsg_host_dispatch, 0, NULL);
+ q = bsg_setup_queue(dev, bsg_name, iscsi_bsg_host_dispatch, 0);
if (IS_ERR(q)) {
shost_printk(KERN_ERR, shost, "bsg interface failed to "
"initialize - no request queue\n");
diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index 08acbabfae07..e2953b416746 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -187,16 +187,6 @@ static int sas_smp_dispatch(struct bsg_job *job)
return 0;
}
-static void sas_host_release(struct device *dev)
-{
- struct Scsi_Host *shost = dev_to_shost(dev);
- struct sas_host_attrs *sas_host = to_sas_host_attrs(shost);
- struct request_queue *q = sas_host->q;
-
- if (q)
- blk_cleanup_queue(q);
-}
-
static int sas_bsg_initialize(struct Scsi_Host *shost, struct sas_rphy *rphy)
{
struct request_queue *q;
@@ -208,7 +198,7 @@ static int sas_bsg_initialize(struct Scsi_Host *shost, struct sas_rphy *rphy)
if (rphy) {
q = bsg_setup_queue(&rphy->dev, dev_name(&rphy->dev),
- sas_smp_dispatch, 0, NULL);
+ sas_smp_dispatch, 0);
if (IS_ERR(q))
return PTR_ERR(q);
rphy->q = q;
@@ -217,7 +207,7 @@ static int sas_bsg_initialize(struct Scsi_Host *shost, struct sas_rphy *rphy)
snprintf(name, sizeof(name), "sas_host%d", shost->host_no);
q = bsg_setup_queue(&shost->shost_gendev, name,
- sas_smp_dispatch, 0, sas_host_release);
+ sas_smp_dispatch, 0);
if (IS_ERR(q))
return PTR_ERR(q);
to_sas_host_attrs(shost)->q = q;
@@ -260,8 +250,11 @@ static int sas_host_remove(struct transport_container *tc, struct device *dev,
struct Scsi_Host *shost = dev_to_shost(dev);
struct request_queue *q = to_sas_host_attrs(shost)->q;
- if (q)
+ if (q) {
bsg_unregister_queue(q);
+ blk_cleanup_queue(q);
+ }
+
return 0;
}
diff --git a/include/linux/bsg-lib.h b/include/linux/bsg-lib.h
index 28a7ccc55c89..6aeaf6472665 100644
--- a/include/linux/bsg-lib.h
+++ b/include/linux/bsg-lib.h
@@ -72,8 +72,7 @@ struct bsg_job {
void bsg_job_done(struct bsg_job *job, int result,
unsigned int reply_payload_rcv_len);
struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
- bsg_job_fn *job_fn, int dd_job_size,
- void (*release)(struct device *));
+ bsg_job_fn *job_fn, int dd_job_size);
void bsg_job_put(struct bsg_job *job);
int __must_check bsg_job_get(struct bsg_job *job);
diff --git a/include/linux/bsg.h b/include/linux/bsg.h
index 0c7dd9ceb139..dac37b6e00ec 100644
--- a/include/linux/bsg.h
+++ b/include/linux/bsg.h
@@ -17,17 +17,13 @@ struct bsg_ops {
struct bsg_class_device {
struct device *class_dev;
- struct device *parent;
int minor;
struct request_queue *queue;
- struct kref ref;
const struct bsg_ops *ops;
- void (*release)(struct device *);
};
int bsg_register_queue(struct request_queue *q, struct device *parent,
- const char *name, const struct bsg_ops *ops,
- void (*release)(struct device *));
+ const char *name, const struct bsg_ops *ops);
int bsg_scsi_register_queue(struct request_queue *q, struct device *parent);
void bsg_unregister_queue(struct request_queue *q);
#else
--
2.17.0
