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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 /io_uring/eventfd.c
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 'io_uring/eventfd.c')
-rw-r--r--io_uring/eventfd.c173
1 files changed, 173 insertions, 0 deletions
diff --git a/io_uring/eventfd.c b/io_uring/eventfd.c
new file mode 100644
index 000000000..63fe6e5d7
--- /dev/null
+++ b/io_uring/eventfd.c
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/eventfd.h>
+#include <linux/eventpoll.h>
+#include <linux/io_uring.h>
+#include <linux/io_uring_types.h>
+
+#include "io-wq.h"
+#include "eventfd.h"
+
+struct io_ev_fd {
+ struct eventfd_ctx *cq_ev_fd;
+ unsigned int eventfd_async;
+ /* protected by ->completion_lock */
+ unsigned last_cq_tail;
+ refcount_t refs;
+ atomic_t ops;
+ struct rcu_head rcu;
+};
+
+enum {
+ IO_EVENTFD_OP_SIGNAL_BIT,
+};
+
+static void io_eventfd_free(struct rcu_head *rcu)
+{
+ struct io_ev_fd *ev_fd = container_of(rcu, struct io_ev_fd, rcu);
+
+ eventfd_ctx_put(ev_fd->cq_ev_fd);
+ kfree(ev_fd);
+}
+
+static void io_eventfd_put(struct io_ev_fd *ev_fd)
+{
+ if (refcount_dec_and_test(&ev_fd->refs))
+ call_rcu(&ev_fd->rcu, io_eventfd_free);
+}
+
+static void io_eventfd_do_signal(struct rcu_head *rcu)
+{
+ struct io_ev_fd *ev_fd = container_of(rcu, struct io_ev_fd, rcu);
+
+ atomic_andnot(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops);
+ eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);
+ io_eventfd_put(ev_fd);
+}
+
+/*
+ * Returns true if the caller should put the ev_fd reference, false if not.
+ */
+static bool __io_eventfd_signal(struct io_ev_fd *ev_fd, bool defer)
+{
+ if (!defer && eventfd_signal_allowed()) {
+ eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);
+ return true;
+ }
+ if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops)) {
+ call_rcu_hurry(&ev_fd->rcu, io_eventfd_do_signal);
+ return false;
+ }
+ return true;
+}
+
+/*
+ * Trigger if eventfd_async isn't set, or if it's set and the caller is
+ * an async worker.
+ */
+static bool io_eventfd_trigger(struct io_ev_fd *ev_fd)
+{
+ return !ev_fd->eventfd_async || io_wq_current_is_worker();
+}
+
+void io_eventfd_signal(struct io_ring_ctx *ctx, bool cqe_event, bool defer)
+{
+ bool skip = false;
+ struct io_ev_fd *ev_fd;
+ struct io_rings *rings;
+
+ guard(rcu)();
+
+ rings = rcu_dereference(ctx->rings_rcu);
+ if (!rings)
+ return;
+ if (READ_ONCE(rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
+ return;
+ ev_fd = rcu_dereference(ctx->io_ev_fd);
+ /*
+ * Check again if ev_fd exists in case an io_eventfd_unregister call
+ * completed between the NULL check of ctx->io_ev_fd at the start of
+ * the function and rcu_read_lock.
+ */
+ if (!ev_fd)
+ return;
+ if (!io_eventfd_trigger(ev_fd) || !refcount_inc_not_zero(&ev_fd->refs))
+ return;
+
+ if (cqe_event) {
+ /*
+ * Eventfd should only get triggered when at least one event
+ * has been posted. Some applications rely on the eventfd
+ * notification count only changing IFF a new CQE has been
+ * added to the CQ ring. There's no dependency on 1:1
+ * relationship between how many times this function is called
+ * (and hence the eventfd count) and number of CQEs posted to
+ * the CQ ring.
+ */
+ spin_lock(&ctx->completion_lock);
+ skip = ctx->cached_cq_tail == ev_fd->last_cq_tail;
+ ev_fd->last_cq_tail = ctx->cached_cq_tail;
+ spin_unlock(&ctx->completion_lock);
+ }
+
+ if (skip || __io_eventfd_signal(ev_fd, defer))
+ io_eventfd_put(ev_fd);
+}
+
+int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg,
+ unsigned int eventfd_async)
+{
+ struct io_ev_fd *ev_fd;
+ __s32 __user *fds = arg;
+ int fd;
+
+ ev_fd = rcu_dereference_protected(ctx->io_ev_fd,
+ lockdep_is_held(&ctx->uring_lock));
+ if (ev_fd)
+ return -EBUSY;
+
+ if (copy_from_user(&fd, fds, sizeof(*fds)))
+ return -EFAULT;
+
+ ev_fd = kmalloc_obj(*ev_fd);
+ if (!ev_fd)
+ return -ENOMEM;
+
+ ev_fd->cq_ev_fd = eventfd_ctx_fdget(fd);
+ if (IS_ERR(ev_fd->cq_ev_fd)) {
+ int ret = PTR_ERR(ev_fd->cq_ev_fd);
+
+ kfree(ev_fd);
+ return ret;
+ }
+
+ spin_lock(&ctx->completion_lock);
+ ev_fd->last_cq_tail = ctx->cached_cq_tail;
+ spin_unlock(&ctx->completion_lock);
+
+ ev_fd->eventfd_async = eventfd_async;
+ ctx->int_flags |= IO_RING_F_HAS_EVFD;
+ refcount_set(&ev_fd->refs, 1);
+ atomic_set(&ev_fd->ops, 0);
+ rcu_assign_pointer(ctx->io_ev_fd, ev_fd);
+ return 0;
+}
+
+int io_eventfd_unregister(struct io_ring_ctx *ctx)
+{
+ struct io_ev_fd *ev_fd;
+
+ ev_fd = rcu_dereference_protected(ctx->io_ev_fd,
+ lockdep_is_held(&ctx->uring_lock));
+ if (ev_fd) {
+ ctx->int_flags &= ~IO_RING_F_HAS_EVFD;
+ rcu_assign_pointer(ctx->io_ev_fd, NULL);
+ io_eventfd_put(ev_fd);
+ return 0;
+ }
+
+ return -ENXIO;
+}