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USB: make intf.pm_usage an atomic_t

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This patch (as1260) changes the pm_usage_cnt field in struct
usb_interface from an int to an atomic_t.  This is so that drivers can
invoke the usb_autopm_get_interface_async() and
usb_autopm_put_interface_async() routines without locking and without
fear of corrupting the pm_usage_cnt value.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern
2009-06-29 11:00:01 -04:00
committed by Greg Kroah-Hartman
parent 7cbe5dca39
commit ccf5b801ce
3 changed files with 28 additions and 21 deletions
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6
include/linux/usb.h
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@ -195,7 +195,7 @@ struct usb_interface {
struct device dev; /* interface specific device info */
struct device *usb_dev;
int pm_usage_cnt; /* usage counter for autosuspend */
atomic_t pm_usage_cnt; /* usage counter for autosuspend */
struct work_struct reset_ws; /* for resets in atomic context */
};
#define to_usb_interface(d) container_of(d, struct usb_interface, dev)
@ -551,13 +551,13 @@ extern void usb_autopm_put_interface_async(struct usb_interface *intf);
static inline void usb_autopm_enable(struct usb_interface *intf)
{
intf->pm_usage_cnt = 0;
atomic_set(&intf->pm_usage_cnt, 0);
usb_autopm_set_interface(intf);
}
static inline void usb_autopm_disable(struct usb_interface *intf)
{
intf->pm_usage_cnt = 1;
atomic_set(&intf->pm_usage_cnt, 1);
usb_autopm_set_interface(intf);
}