From b620ecbd17a03cacd06f014a5d3f3a11285ce053 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Fri, 8 Mar 2024 16:05:24 -0700 Subject: vfio: Introduce interface to flush virqfd inject workqueue In order to synchronize changes that can affect the thread callback, introduce an interface to force a flush of the inject workqueue. The irqfd pointer is only valid under spinlock, but the workqueue cannot be flushed under spinlock. Therefore the flush work for the irqfd is queued under spinlock. The vfio_irqfd_cleanup_wq workqueue is re-used for queuing this work such that flushing the workqueue is also ordered relative to shutdown. Reviewed-by: Kevin Tian Reviewed-by: Reinette Chatre Reviewed-by: Eric Auger Link: https://lore.kernel.org/r/20240308230557.805580-4-alex.williamson@redhat.com Signed-off-by: Alex Williamson --- drivers/vfio/virqfd.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'drivers/vfio') diff --git a/drivers/vfio/virqfd.c b/drivers/vfio/virqfd.c index 29c564b7a6e1..532269133801 100644 --- a/drivers/vfio/virqfd.c +++ b/drivers/vfio/virqfd.c @@ -101,6 +101,13 @@ static void virqfd_inject(struct work_struct *work) virqfd->thread(virqfd->opaque, virqfd->data); } +static void virqfd_flush_inject(struct work_struct *work) +{ + struct virqfd *virqfd = container_of(work, struct virqfd, flush_inject); + + flush_work(&virqfd->inject); +} + int vfio_virqfd_enable(void *opaque, int (*handler)(void *, void *), void (*thread)(void *, void *), @@ -124,6 +131,7 @@ int vfio_virqfd_enable(void *opaque, INIT_WORK(&virqfd->shutdown, virqfd_shutdown); INIT_WORK(&virqfd->inject, virqfd_inject); + INIT_WORK(&virqfd->flush_inject, virqfd_flush_inject); irqfd = fdget(fd); if (!irqfd.file) { @@ -213,3 +221,16 @@ void vfio_virqfd_disable(struct virqfd **pvirqfd) flush_workqueue(vfio_irqfd_cleanup_wq); } EXPORT_SYMBOL_GPL(vfio_virqfd_disable); + +void vfio_virqfd_flush_thread(struct virqfd **pvirqfd) +{ + unsigned long flags; + + spin_lock_irqsave(&virqfd_lock, flags); + if (*pvirqfd && (*pvirqfd)->thread) + queue_work(vfio_irqfd_cleanup_wq, &(*pvirqfd)->flush_inject); + spin_unlock_irqrestore(&virqfd_lock, flags); + + flush_workqueue(vfio_irqfd_cleanup_wq); +} +EXPORT_SYMBOL_GPL(vfio_virqfd_flush_thread); -- cgit v1.2.3