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fpga manager: ensure lifetime with of_fpga_mgr_get 

Ensure device and driver lifetime from of_fpga_mgr_get() to
fpga_mgr_put().

* Don't put_device() in of_fpga_mgr_get, do it in fpga_mgr_put().
  (still do put_device if there is an error).
* Do module_get on the low level driver.
* Don't need to module_get(THIS_MODULE) since we won't be allowed
  to unload the fpga manager core without unloading low level
  driver first.
* Remove unnedessary null check for node pointer.

Signed-off-by: Alan Tull <atull@opensource.altera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Tull 2015-10-22 12:38:37 -05:00 committed by Greg Kroah-Hartman
parent 4d10eaff5b
commit 654ba4cc0f
1 changed files with 17 additions and 15 deletions
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30
drivers/fpga/fpga-mgr.c
View File

@ -204,9 +204,7 @@ struct fpga_manager *of_fpga_mgr_get(struct device_node *node)
{
struct fpga_manager *mgr;
struct device *dev;
if (!node)
return ERR_PTR(-EINVAL);
int ret = -ENODEV;
dev = class_find_device(fpga_mgr_class, NULL, node,
fpga_mgr_of_node_match);
@ -214,20 +212,25 @@ struct fpga_manager *of_fpga_mgr_get(struct device_node *node)
return ERR_PTR(-ENODEV);
mgr = to_fpga_manager(dev);
put_device(dev);
if (!mgr)
return ERR_PTR(-ENODEV);
goto err_dev;
/* Get exclusive use of fpga manager */
if (!mutex_trylock(&mgr->ref_mutex))
return ERR_PTR(-EBUSY);
if (!try_module_get(THIS_MODULE)) {
mutex_unlock(&mgr->ref_mutex);
return ERR_PTR(-ENODEV);
if (!mutex_trylock(&mgr->ref_mutex)) {
ret = -EBUSY;
goto err_dev;
}
if (!try_module_get(dev->parent->driver->owner))
goto err_ll_mod;
return mgr;
err_ll_mod:
mutex_unlock(&mgr->ref_mutex);
err_dev:
put_device(dev);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(of_fpga_mgr_get);
@ -237,10 +240,9 @@ EXPORT_SYMBOL_GPL(of_fpga_mgr_get);
*/
void fpga_mgr_put(struct fpga_manager *mgr)
{
if (mgr) {
module_put(THIS_MODULE);
module_put(mgr->dev.parent->driver->owner);
mutex_unlock(&mgr->ref_mutex);
}
put_device(&mgr->dev);
}
EXPORT_SYMBOL_GPL(fpga_mgr_put);