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IB/uverbs: Avoid a crash on device hot remove

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Wait until all users have closed their device context before allowing
device unregistration to complete.  This prevents a crash caused by
referring to stale data structures.

A better solution would be to have a way to revoke contexts rather
than waiting for userspace to close the context, but that's a much
bigger change that will have to wait.  For now let's at least avoid
the crash.

Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Jack Morgenstein 2006-08-03 10:56:42 -07:00 committed by Roland Dreier
parent 8ddc7c5326
commit fd60ae404f
2 changed files with 9 additions and 1 deletions
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2
drivers/infiniband/core/uverbs.h
View file

@ -42,6 +42,7 @@
#include <linux/kref.h>
#include <linux/idr.h>
#include <linux/mutex.h>
#include <linux/completion.h>
#include <rdma/ib_verbs.h>
#include <rdma/ib_user_verbs.h>
@ -69,6 +70,7 @@
struct ib_uverbs_device {
struct kref ref;
struct completion comp;
int devnum;
struct cdev *dev;
struct class_device *class_dev;

8
drivers/infiniband/core/uverbs_main.c
View file

@ -122,7 +122,7 @@ static void ib_uverbs_release_dev(struct kref *ref)
struct ib_uverbs_device *dev =
container_of(ref, struct ib_uverbs_device, ref);
kfree(dev);
complete(&dev->comp);
}
void ib_uverbs_release_ucq(struct ib_uverbs_file *file,
@ -740,6 +740,7 @@ static void ib_uverbs_add_one(struct ib_device *device)
return;
kref_init(&uverbs_dev->ref);
init_completion(&uverbs_dev->comp);
spin_lock(&map_lock);
uverbs_dev->devnum = find_first_zero_bit(dev_map, IB_UVERBS_MAX_DEVICES);
@ -793,6 +794,8 @@ static void ib_uverbs_add_one(struct ib_device *device)
err:
kref_put(&uverbs_dev->ref, ib_uverbs_release_dev);
wait_for_completion(&uverbs_dev->comp);
kfree(uverbs_dev);
return;
}
@ -812,7 +815,10 @@ static void ib_uverbs_remove_one(struct ib_device *device)
spin_unlock(&map_lock);
clear_bit(uverbs_dev->devnum, dev_map);
kref_put(&uverbs_dev->ref, ib_uverbs_release_dev);
wait_for_completion(&uverbs_dev->comp);
kfree(uverbs_dev);
}
static int uverbs_event_get_sb(struct file_system_type *fs_type, int flags,