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| author | David Altobelli <david.altobelli@hp.com> | 2009-09-18 23:46:26 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-12-11 22:24:51 +0300 |
| commit | 68ea809af47d8a4dd92dd3a8720882767fdf51b6 (patch) | |
| tree | 3844a706dabb83fb6535181471cccde7beba489e | |
| parent | d71cb81af3817193bc605de061da0499934263a6 (diff) | |
| download | linux-68ea809af47d8a4dd92dd3a8720882767fdf51b6.tar.xz | |
hpilo: add locking comment
Add explanation about lock nesting and purpose of each lock in hpilo.
Signed-off-by: David Altobelli <david.altobelli@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/misc/hpilo.h | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/misc/hpilo.h b/drivers/misc/hpilo.h index 38576050776a..247eb386a973 100644 --- a/drivers/misc/hpilo.h +++ b/drivers/misc/hpilo.h @@ -44,9 +44,20 @@ struct ilo_hwinfo { struct pci_dev *ilo_dev; + /* + * open_lock serializes ccb_cnt during open and close + * [ irq disabled ] + * -> alloc_lock used when adding/removing/searching ccb_alloc, + * which represents all ccbs open on the device + * --> fifo_lock controls access to fifo queues shared with hw + * + * Locks must be taken in this order, but open_lock and alloc_lock + * are optional, they do not need to be held in order to take a + * lower level lock. + */ + spinlock_t open_lock; spinlock_t alloc_lock; spinlock_t fifo_lock; - spinlock_t open_lock; struct cdev cdev; }; |