diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2010-06-22 16:39:10 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-08-10 14:35:37 -0700 |
| commit | 541c7d432f76771079e7c295d596ea47cc6a3030 (patch) | |
| tree | 9e04330713366d21849cecf0f3fd2f2c1834574d /include/linux/usb | |
| parent | 89ba85d4015b7fa738b35bcc228075c117a9a578 (diff) | |
USB: convert usb_hcd bitfields into atomic flags
This patch (as1393) converts several of the single-bit fields in
struct usb_hcd to atomic flags. This is for safety's sake; not all
CPUs can update bitfield values atomically, and these flags are used
in multiple contexts.
The flag fields that are set only during registration or removal can
remain as they are, since non-atomic accesses at those times will not
cause any problems.
(Strictly speaking, the authorized_default flag should become atomic
as well. I didn't bother with it because it gets changed only via
sysfs. It can be done later, if anyone wants.)
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'include/linux/usb')
| -rw-r--r-- | include/linux/usb/hcd.h | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h index 9b867e64a0f..f8f8fa7a56e 100644 --- a/include/linux/usb/hcd.h +++ b/include/linux/usb/hcd.h @@ -89,19 +89,31 @@ struct usb_hcd { */ const struct hc_driver *driver; /* hw-specific hooks */ - /* Flags that need to be manipulated atomically */ + /* Flags that need to be manipulated atomically because they can + * change while the host controller is running. Always use + * set_bit() or clear_bit() to change their values. + */ unsigned long flags; -#define HCD_FLAG_HW_ACCESSIBLE 0x00000001 -#define HCD_FLAG_SAW_IRQ 0x00000002 +#define HCD_FLAG_HW_ACCESSIBLE 0 /* at full power */ +#define HCD_FLAG_SAW_IRQ 1 +#define HCD_FLAG_POLL_RH 2 /* poll for rh status? */ +#define HCD_FLAG_POLL_PENDING 3 /* status has changed? */ + + /* The flags can be tested using these macros; they are likely to + * be slightly faster than test_bit(). + */ +#define HCD_HW_ACCESSIBLE(hcd) ((hcd)->flags & (1U << HCD_FLAG_HW_ACCESSIBLE)) +#define HCD_SAW_IRQ(hcd) ((hcd)->flags & (1U << HCD_FLAG_SAW_IRQ)) +#define HCD_POLL_RH(hcd) ((hcd)->flags & (1U << HCD_FLAG_POLL_RH)) +#define HCD_POLL_PENDING(hcd) ((hcd)->flags & (1U << HCD_FLAG_POLL_PENDING)) + /* Flags that get set only during HCD registration or removal. */ unsigned rh_registered:1;/* is root hub registered? */ unsigned rh_pollable:1; /* may we poll the root hub? */ /* The next flag is a stopgap, to be removed when all the HCDs * support the new root-hub polling mechanism. */ unsigned uses_new_polling:1; - unsigned poll_rh:1; /* poll for rh status? */ - unsigned poll_pending:1; /* status has changed? */ unsigned wireless:1; /* Wireless USB HCD */ unsigned authorized_default:1; unsigned has_tt:1; /* Integrated TT in root hub */ |