summaryrefslogtreecommitdiffstats
path: root/drivers/md/dm-vdo/wait-queue.h
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
commitcf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch)
tree757a3d280760c654767631cab5ad8af2d86d1848 /drivers/md/dm-vdo/wait-queue.h
downloadlinux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.tar.gz
linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.zip
Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij: "Core changes: - Use the non-blocking mux_state_try_select() in the generic MUX pin control back-end - Free pin maps on pinctrl_generic_to_map() failure in the core helpers New hardware pin control: - Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC (this is for the low power audio, LPASS = Low Power Audio SubSystem portions) - Upboard support on top of the Intel pin controller - Apple T6030 and T6031 support (just compatible strings) - Samsung Exynos 8855 SoC - Mediatek MT6858 SoC - Rockchip RK3308B and RV1106 SoCs - Airoha EN7523 and AN7563 SoCs Improvements: - Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable - Qualcomm improvements on top of the Qualcomm PDC (power domain controller) irqchip improvements from tglx:s tree - Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups - The NPCM8xx driver has been put into shape fixing many pin and group definitions - Some non-urgent Tegra 264 pin assignments are fixed up - Some non-urgent fixups to Airoha AN7581 and AN7583 registers and pin assignments, missing features etc" * tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits) dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema pinctrl: meson: sync some modify from A4 pinctrl: meson: a4: Add input enable pin configuration pinctrl: realtek: rtd1625: remove unused group name spdif_sel pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13 dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema Revert "Merge branch 'ib-rsk7204' into devel" pinctrl: rockchip: Add RV1106 pinctrl support dt-bindings: pinctrl: rockchip: Add RV1106 compatible pinctrl: rockchip: Decode drive strength in the get function pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable pinctrl: airoha: add support of an7563 SoC dt-bindings: pinctrl: airoha: add support of an7563 pin controller pinctrl: airoha: try to find chip scu node by phandle first pinctrl: airoha: add support of en7523 SoC dt-bindings: pinctrl: airoha: add support of en7523 pin controller pinctrl: airoha: an7583: add support for olt pinmux pinctrl: airoha: an7583: add support for pon_alt pinmux pinctrl: airoha: an7583: add support for npu_uart pinmux dt-bindings: pinctrl: airoha: an7583: add missed features ...
Diffstat (limited to 'drivers/md/dm-vdo/wait-queue.h')
-rw-r--r--drivers/md/dm-vdo/wait-queue.h138
1 files changed, 138 insertions, 0 deletions
diff --git a/drivers/md/dm-vdo/wait-queue.h b/drivers/md/dm-vdo/wait-queue.h
new file mode 100644
index 000000000..7e8ee6afe
--- /dev/null
+++ b/drivers/md/dm-vdo/wait-queue.h
@@ -0,0 +1,138 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2023 Red Hat
+ */
+
+#ifndef VDO_WAIT_QUEUE_H
+#define VDO_WAIT_QUEUE_H
+
+#include <linux/compiler.h>
+#include <linux/types.h>
+
+/**
+ * A vdo_wait_queue is a circular singly linked list of entries waiting to be notified
+ * of a change in a condition. Keeping a circular list allows the vdo_wait_queue
+ * structure to simply be a pointer to the tail (newest) entry, supporting
+ * constant-time enqueue and dequeue operations. A null pointer is an empty waitq.
+ *
+ * An empty waitq:
+ * waitq0.last_waiter -> NULL
+ *
+ * A singleton waitq:
+ * waitq1.last_waiter -> entry1 -> entry1 -> [...]
+ *
+ * A three-element waitq:
+ * waitq2.last_waiter -> entry3 -> entry1 -> entry2 -> entry3 -> [...]
+ *
+ * linux/wait.h's wait_queue_head is _not_ used because vdo_wait_queue's
+ * interface is much less complex (doesn't need locking, priorities or timers).
+ * Made possible by vdo's thread-based resource allocation and locking; and
+ * the polling nature of vdo_wait_queue consumers.
+ *
+ * FIXME: could be made to use a linux/list.h's list_head but its extra barriers
+ * really aren't needed. Nor is a doubly linked list, but vdo_wait_queue could
+ * make use of __list_del_clearprev() -- but that would compromise the ability
+ * to make full use of linux's list interface.
+ */
+
+struct vdo_waiter;
+
+struct vdo_wait_queue {
+ /* The tail of the queue, the last (most recently added) entry */
+ struct vdo_waiter *last_waiter;
+ /* The number of waiters currently in the queue */
+ size_t length;
+};
+
+/**
+ * vdo_waiter_callback_fn - Callback type that will be called to resume processing
+ * of a waiter after it has been removed from its wait queue.
+ */
+typedef void (*vdo_waiter_callback_fn)(struct vdo_waiter *waiter, void *context);
+
+/**
+ * vdo_waiter_match_fn - Method type for waiter matching methods.
+ *
+ * Returns false if the waiter does not match.
+ */
+typedef bool (*vdo_waiter_match_fn)(struct vdo_waiter *waiter, void *context);
+
+/* The structure for entries in a vdo_wait_queue. */
+struct vdo_waiter {
+ /*
+ * The next waiter in the waitq. If this entry is the last waiter, then this
+ * is actually a pointer back to the head of the waitq.
+ */
+ struct vdo_waiter *next_waiter;
+
+ /* Optional waiter-specific callback to invoke when dequeuing this waiter. */
+ vdo_waiter_callback_fn callback;
+};
+
+/**
+ * vdo_waiter_is_waiting() - Check whether a waiter is waiting.
+ * @waiter: The waiter to check.
+ *
+ * Return: true if the waiter is on some vdo_wait_queue.
+ */
+static inline bool vdo_waiter_is_waiting(struct vdo_waiter *waiter)
+{
+ return (waiter->next_waiter != NULL);
+}
+
+/**
+ * vdo_waitq_init() - Initialize a vdo_wait_queue.
+ * @waitq: The vdo_wait_queue to initialize.
+ */
+static inline void vdo_waitq_init(struct vdo_wait_queue *waitq)
+{
+ *waitq = (struct vdo_wait_queue) {
+ .last_waiter = NULL,
+ .length = 0,
+ };
+}
+
+/**
+ * vdo_waitq_has_waiters() - Check whether a vdo_wait_queue has any entries waiting.
+ * @waitq: The vdo_wait_queue to query.
+ *
+ * Return: true if there are any waiters in the waitq.
+ */
+static inline bool __must_check vdo_waitq_has_waiters(const struct vdo_wait_queue *waitq)
+{
+ return (waitq->last_waiter != NULL);
+}
+
+void vdo_waitq_enqueue_waiter(struct vdo_wait_queue *waitq,
+ struct vdo_waiter *waiter);
+
+struct vdo_waiter *vdo_waitq_dequeue_waiter(struct vdo_wait_queue *waitq);
+
+void vdo_waitq_notify_all_waiters(struct vdo_wait_queue *waitq,
+ vdo_waiter_callback_fn callback, void *context);
+
+bool vdo_waitq_notify_next_waiter(struct vdo_wait_queue *waitq,
+ vdo_waiter_callback_fn callback, void *context);
+
+void vdo_waitq_transfer_all_waiters(struct vdo_wait_queue *from_waitq,
+ struct vdo_wait_queue *to_waitq);
+
+struct vdo_waiter *vdo_waitq_get_first_waiter(const struct vdo_wait_queue *waitq);
+
+void vdo_waitq_dequeue_matching_waiters(struct vdo_wait_queue *waitq,
+ vdo_waiter_match_fn waiter_match,
+ void *match_context,
+ struct vdo_wait_queue *matched_waitq);
+
+/**
+ * vdo_waitq_num_waiters() - Return the number of waiters in a vdo_wait_queue.
+ * @waitq: The vdo_wait_queue to query.
+ *
+ * Return: The number of waiters in the waitq.
+ */
+static inline size_t __must_check vdo_waitq_num_waiters(const struct vdo_wait_queue *waitq)
+{
+ return waitq->length;
+}
+
+#endif /* VDO_WAIT_QUEUE_H */