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fpga: mgr: separate getting/locking FPGA manager

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Previously when the user gets a FPGA manager, it was locked
and nobody else could use it for programming.

This commit makes it straightforward to save a reference to an
FPGA manager and only lock it when programming the FPGA.

Add functions that get an FPGA manager's mutex for exclusive use:
* fpga_mgr_lock
* fpga_mgr_unlock

The following functions no longer lock an FPGA manager's mutex:
* of_fpga_mgr_get
* fpga_mgr_get
* fpga_mgr_put

Signed-off-by: Alan Tull <atull@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Tull 2017-11-15 14:20:13 -06:00 • committed by Greg Kroah-Hartman
parent 5cf0c7f650
commit ebf877a51a
4 changed files with 77 additions and 27 deletions
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52
drivers/fpga/fpga-mgr.c
View file

@ -410,28 +410,19 @@ ATTRIBUTE_GROUPS(fpga_mgr);
static struct fpga_manager *__fpga_mgr_get(struct device *dev)
{
struct fpga_manager *mgr;
int ret = -ENODEV;
mgr = to_fpga_manager(dev);
if (!mgr)
goto err_dev;
/* Get exclusive use of fpga manager */
if (!mutex_trylock(&mgr->ref_mutex)) {
ret = -EBUSY;
goto err_dev;
}
if (!try_module_get(dev->parent->driver->owner))
goto err_ll_mod;
goto err_dev;
return mgr;
err_ll_mod:
mutex_unlock(&mgr->ref_mutex);
err_dev:
put_device(dev);
return ERR_PTR(ret);
return ERR_PTR(-ENODEV);
}
static int fpga_mgr_dev_match(struct device *dev, const void *data)
@ -440,10 +431,10 @@ static int fpga_mgr_dev_match(struct device *dev, const void *data)
}
/**
* fpga_mgr_get - get an exclusive reference to a fpga mgr
* fpga_mgr_get - get a reference to a fpga mgr
* @dev: parent device that fpga mgr was registered with
*
* Given a device, get an exclusive reference to a fpga mgr.
* Given a device, get a reference to a fpga mgr.
*
* Return: fpga manager struct or IS_ERR() condition containing error code.
*/
@ -464,10 +455,10 @@ static int fpga_mgr_of_node_match(struct device *dev, const void *data)
}
/**
* of_fpga_mgr_get - get an exclusive reference to a fpga mgr
* of_fpga_mgr_get - get a reference to a fpga mgr
* @node: device node
*
* Given a device node, get an exclusive reference to a fpga mgr.
* Given a device node, get a reference to a fpga mgr.
*
* Return: fpga manager struct or IS_ERR() condition containing error code.
*/
@ -491,11 +482,40 @@ EXPORT_SYMBOL_GPL(of_fpga_mgr_get);
void fpga_mgr_put(struct fpga_manager *mgr)
{
module_put(mgr->dev.parent->driver->owner);
mutex_unlock(&mgr->ref_mutex);
put_device(&mgr->dev);
}
EXPORT_SYMBOL_GPL(fpga_mgr_put);
/**
* fpga_mgr_lock - Lock FPGA manager for exclusive use
* @mgr: fpga manager
*
* Given a pointer to FPGA Manager (from fpga_mgr_get() or
* of_fpga_mgr_put()) attempt to get the mutex.
*
* Return: 0 for success or -EBUSY
*/
int fpga_mgr_lock(struct fpga_manager *mgr)
{
if (!mutex_trylock(&mgr->ref_mutex)) {
dev_err(&mgr->dev, "FPGA manager is in use.\n");
return -EBUSY;
}
return 0;
}
EXPORT_SYMBOL_GPL(fpga_mgr_lock);
/**
* fpga_mgr_unlock - Unlock FPGA manager
* @mgr: fpga manager
*/
void fpga_mgr_unlock(struct fpga_manager *mgr)
{
mutex_unlock(&mgr->ref_mutex);
}
EXPORT_SYMBOL_GPL(fpga_mgr_unlock);
/**
* fpga_mgr_register - register a low level fpga manager driver
* @dev: fpga manager device from pdev