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IB/uverbs: Fix reference counting usage of event files 

Fix the reference counting usage to be handled in the event file
creation/destruction function, instead of being done by the caller.
This is done for both async/non-async event files.

Based on Jason Gunthorpe report at https://www.mail-archive.com/
linux-rdma@vger.kernel.org/msg24680.html:
"The existing code for this is broken, in ib_uverbs_get_context all
the error paths between ib_uverbs_alloc_event_file and the
kref_get(file->ref) are wrong - this will result in fput() which will
call ib_uverbs_event_close, which will try to do kref_put and
ib_unregister_event_handler - which are no longer paired."

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Yishai Hadas 2015-08-13 18:32:02 +03:00 committed by Doug Ledford
parent 7dd78647a2
commit 03c40442a0
3 changed files with 40 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/infiniband/core/uverbs.h
View File

@ -178,6 +178,7 @@ void idr_remove_uobj(struct idr *idp, struct ib_uobject *uobj);
struct file *ib_uverbs_alloc_event_file(struct ib_uverbs_file *uverbs_file,
int is_async);
void ib_uverbs_free_async_event_file(struct ib_uverbs_file *uverbs_file);
struct ib_uverbs_event_file *ib_uverbs_lookup_comp_file(int fd);
void ib_uverbs_release_ucq(struct ib_uverbs_file *file,

11
drivers/infiniband/core/uverbs_cmd.c
View File

@ -367,16 +367,6 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
goto err_file;
}
file->async_file = filp->private_data;
INIT_IB_EVENT_HANDLER(&file->event_handler, file->device->ib_dev,
ib_uverbs_event_handler);
ret = ib_register_event_handler(&file->event_handler);
if (ret)
goto err_file;
kref_get(&file->async_file->ref);
kref_get(&file->ref);
file->ucontext = ucontext;
fd_install(resp.async_fd, filp);
@ -386,6 +376,7 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
return in_len;
err_file:
ib_uverbs_free_async_event_file(file);
fput(filp);
err_fd:

44
drivers/infiniband/core/uverbs_main.c
View File

@ -406,10 +406,9 @@ static int ib_uverbs_event_close(struct inode *inode, struct file *filp)
}
spin_unlock_irq(&file->lock);
if (file->is_async) {
if (file->is_async)
ib_unregister_event_handler(&file->uverbs_file->event_handler);
kref_put(&file->uverbs_file->ref, ib_uverbs_release_file);
}
kref_put(&file->uverbs_file->ref, ib_uverbs_release_file);
kref_put(&file->ref, ib_uverbs_release_event_file);
return 0;
@ -541,13 +540,20 @@ void ib_uverbs_event_handler(struct ib_event_handler *handler,
NULL, NULL);
}
void ib_uverbs_free_async_event_file(struct ib_uverbs_file *file)
{
kref_put(&file->async_file->ref, ib_uverbs_release_event_file);
file->async_file = NULL;
}
struct file *ib_uverbs_alloc_event_file(struct ib_uverbs_file *uverbs_file,
int is_async)
{
struct ib_uverbs_event_file *ev_file;
struct file *filp;
int ret;
ev_file = kmalloc(sizeof *ev_file, GFP_KERNEL);
ev_file = kzalloc(sizeof(*ev_file), GFP_KERNEL);
if (!ev_file)
return ERR_PTR(-ENOMEM);
@ -556,15 +562,41 @@ struct file *ib_uverbs_alloc_event_file(struct ib_uverbs_file *uverbs_file,
INIT_LIST_HEAD(&ev_file->event_list);
init_waitqueue_head(&ev_file->poll_wait);
ev_file->uverbs_file = uverbs_file;
kref_get(&ev_file->uverbs_file->ref);
ev_file->async_queue = NULL;
ev_file->is_async = is_async;
ev_file->is_closed = 0;
filp = anon_inode_getfile("[infinibandevent]", &uverbs_event_fops,
ev_file, O_RDONLY);
if (IS_ERR(filp))
kfree(ev_file);
goto err_put_refs;
if (is_async) {
WARN_ON(uverbs_file->async_file);
uverbs_file->async_file = ev_file;
kref_get(&uverbs_file->async_file->ref);
INIT_IB_EVENT_HANDLER(&uverbs_file->event_handler,
uverbs_file->device->ib_dev,
ib_uverbs_event_handler);
ret = ib_register_event_handler(&uverbs_file->event_handler);
if (ret)
goto err_put_file;
/* At that point async file stuff was fully set */
ev_file->is_async = 1;
}
return filp;
err_put_file:
fput(filp);
kref_put(&uverbs_file->async_file->ref, ib_uverbs_release_event_file);
uverbs_file->async_file = NULL;
return ERR_PTR(ret);
err_put_refs:
kref_put(&ev_file->uverbs_file->ref, ib_uverbs_release_file);
kref_put(&ev_file->ref, ib_uverbs_release_event_file);
return filp;
}