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author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-07-29 21:49:22 (GMT) |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-07-29 21:49:22 (GMT) |
commit | 5af310a8ee70dd6a588c8ee1d4487a230a7b7b65 (patch) | |
tree | 38ba23a3b51ab577ea1ddc09772a8556d8957df9 /lib | |
parent | aa57aca8e15a4e11749640e16ac9814f14be24d2 (diff) | |
parent | 4b45efe8526359a11ca60a299bef3aebf413fd77 (diff) | |
download | linux-5af310a8ee70dd6a588c8ee1d4487a230a7b7b65.tar.xz |
Merge tag 'ib-mfd-base-acpi-dma-v4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd into acpi-pm
Pull MFD-related material including ACPI device power management
changes (in addition to MFD, driver core and DMA changes) for v4.3
from Lee Jones.
* tag 'ib-mfd-base-acpi-dma-v4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd:
mfd: Add support for Intel Sunrisepoint LPSS devices
dmaengine: add a driver for Intel integrated DMA 64-bit
mfd: make mfd_remove_devices() iterate in reverse order
driver core: implement device_for_each_child_reverse()
klist: implement klist_prev()
Driver core: wakeup the parent device before trying probe
ACPI / PM: Attach ACPI power domain only once
PM / QoS: Make it possible to expose device latency tolerance to userspace
Diffstat (limited to 'lib')
-rw-r--r-- | lib/klist.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/lib/klist.c b/lib/klist.c index 89b485a..d74cf7a 100644 --- a/lib/klist.c +++ b/lib/klist.c @@ -324,6 +324,47 @@ static struct klist_node *to_klist_node(struct list_head *n) } /** + * klist_prev - Ante up prev node in list. + * @i: Iterator structure. + * + * First grab list lock. Decrement the reference count of the previous + * node, if there was one. Grab the prev node, increment its reference + * count, drop the lock, and return that prev node. + */ +struct klist_node *klist_prev(struct klist_iter *i) +{ + void (*put)(struct klist_node *) = i->i_klist->put; + struct klist_node *last = i->i_cur; + struct klist_node *prev; + + spin_lock(&i->i_klist->k_lock); + + if (last) { + prev = to_klist_node(last->n_node.prev); + if (!klist_dec_and_del(last)) + put = NULL; + } else + prev = to_klist_node(i->i_klist->k_list.prev); + + i->i_cur = NULL; + while (prev != to_klist_node(&i->i_klist->k_list)) { + if (likely(!knode_dead(prev))) { + kref_get(&prev->n_ref); + i->i_cur = prev; + break; + } + prev = to_klist_node(prev->n_node.prev); + } + + spin_unlock(&i->i_klist->k_lock); + + if (put && last) + put(last); + return i->i_cur; +} +EXPORT_SYMBOL_GPL(klist_prev); + +/** * klist_next - Ante up next node in list. * @i: Iterator structure. * |