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authorAlex Williamson <alex.williamson@redhat.com>2024-03-08 16:05:24 -0700
committerAlex Williamson <alex.williamson@redhat.com>2024-03-11 13:08:52 -0600
commitb620ecbd17a03cacd06f014a5d3f3a11285ce053 (patch)
tree9d7a9e555f51df588944b834daa552a86abd2c2f /drivers/vfio
parent810cd4bb53456d0503cc4e7934e063835152c1b7 (diff)
downloadlwn-b620ecbd17a03cacd06f014a5d3f3a11285ce053.tar.gz
lwn-b620ecbd17a03cacd06f014a5d3f3a11285ce053.zip
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 <kevin.tian@intel.com> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Reviewed-by: Eric Auger <eric.auger@redhat.com> Link: https://lore.kernel.org/r/20240308230557.805580-4-alex.williamson@redhat.com Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/virqfd.c21
1 files changed, 21 insertions, 0 deletions
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);