virtio_reset_device() now calls synchronize_cbs to wait for running callbacks. Its synchronize_rcu() fallback does not cover workqueue or sleepable callbacks.
Add the missing hooks. UML waits for its shared IRQ; TmFIFO takes the existing per-direction locks held around vring_interrupt(). Virtio-vdpa uses a per-device rwlock around its callbacks, which must already be hard-IRQ safe. Remoteproc callbacks can run in hard-IRQ or process context, and rpmsg callbacks can sleep, so use one SRCU domain per rproc. Enter it before looking up the queue. Initialize it in rproc_alloc(), returning NULL if that fails, and clean it up at final release. cleanup_srcu_struct() can sleep, so document that rproc_put() and rproc_free() may sleep when dropping the last reference. These hooks wait for callbacks already running. UML, TmFIFO and remoteproc still allow new callbacks after reset. Suggested-by: Michael S. Tsirkin <[email protected]> Assisted-by: LLM Signed-off-by: Karl Mehltretter <[email protected]> --- arch/um/drivers/virtio_uml.c | 10 ++++++++++ drivers/platform/mellanox/mlxbf-tmfifo.c | 14 ++++++++++++++ drivers/remoteproc/remoteproc_core.c | 10 ++++++++++ drivers/remoteproc/remoteproc_virtio.c | 20 +++++++++++++++++--- drivers/virtio/virtio_vdpa.c | 21 ++++++++++++++++++++- include/linux/remoteproc.h | 3 +++ 6 files changed, 74 insertions(+), 4 deletions(-) diff --git a/arch/um/drivers/virtio_uml.c b/arch/um/drivers/virtio_uml.c index 7425a8548141..baca6b09e9ac 100644 --- a/arch/um/drivers/virtio_uml.c +++ b/arch/um/drivers/virtio_uml.c @@ -20,6 +20,7 @@ * * Based on Virtio MMIO driver by Pawel Moll, copyright 2011-2014, ARM Ltd. */ +#include <linux/interrupt.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> @@ -869,6 +870,14 @@ static void vu_reset(struct virtio_device *vdev) vu_dev->status = 0; } +static void vu_synchronize_cbs(struct virtio_device *vdev) +{ + struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev); + + if (vu_dev->irq >= 0) + synchronize_irq(vu_dev->irq); +} + static void vu_del_vq(struct virtqueue *vq) { struct virtio_uml_vq_info *info = vq->priv; @@ -1121,6 +1130,7 @@ static const struct virtio_config_ops virtio_uml_config_ops = { .reset = vu_reset, .find_vqs = vu_find_vqs, .del_vqs = vu_del_vqs, + .synchronize_cbs = vu_synchronize_cbs, .get_features = vu_get_features, .finalize_features = vu_finalize_features, .bus_name = vu_bus_name, diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c index 3c6408581373..c260e3a1544e 100644 --- a/drivers/platform/mellanox/mlxbf-tmfifo.c +++ b/drivers/platform/mellanox/mlxbf-tmfifo.c @@ -1135,6 +1135,19 @@ static void mlxbf_tmfifo_virtio_reset(struct virtio_device *vdev) tm_vdev->status = 0; } +static void mlxbf_tmfifo_virtio_synchronize_cbs(struct virtio_device *vdev) +{ + struct mlxbf_tmfifo_vdev *tm_vdev = mlxbf_vdev_to_tmfifo(vdev); + struct mlxbf_tmfifo *fifo = tm_vdev->vrings[0].fifo; + unsigned long flags; + int i; + + for (i = 0; i < ARRAY_SIZE(fifo->spin_lock); i++) { + spin_lock_irqsave(&fifo->spin_lock[i], flags); + spin_unlock_irqrestore(&fifo->spin_lock[i], flags); + } +} + /* Read the value of a configuration field. */ static void mlxbf_tmfifo_virtio_get(struct virtio_device *vdev, unsigned int offset, @@ -1179,6 +1192,7 @@ static const struct virtio_config_ops mlxbf_tmfifo_virtio_config_ops = { .find_vqs = mlxbf_tmfifo_virtio_find_vqs, .del_vqs = mlxbf_tmfifo_virtio_del_vqs, .reset = mlxbf_tmfifo_virtio_reset, + .synchronize_cbs = mlxbf_tmfifo_virtio_synchronize_cbs, .set_status = mlxbf_tmfifo_virtio_set_status, .get_status = mlxbf_tmfifo_virtio_get_status, .get = mlxbf_tmfifo_virtio_get, diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c index 1ed406714849..1b139d25ab2b 100644 --- a/drivers/remoteproc/remoteproc_core.c +++ b/drivers/remoteproc/remoteproc_core.c @@ -2410,6 +2410,7 @@ static void rproc_type_release(struct device *dev) dev_info(&rproc->dev, "releasing %s\n", rproc->name); + cleanup_srcu_struct(&rproc->vq_srcu); idr_destroy(&rproc->notifyids); if (rproc->index >= 0) @@ -2507,6 +2508,11 @@ struct rproc *rproc_alloc(struct device *dev, const char *name, if (!rproc) return NULL; + if (init_srcu_struct(&rproc->vq_srcu)) { + kfree(rproc); + return NULL; + } + rproc->priv = &rproc[1]; rproc->auto_boot = true; rproc->elf_class = ELFCLASSNONE; @@ -2571,6 +2577,8 @@ EXPORT_SYMBOL(rproc_alloc); * * If no one holds any reference to rproc anymore, then its refcount would * now drop to zero, and it would be freed. + * + * Context: May sleep if this drops the last reference. */ void rproc_free(struct rproc *rproc) { @@ -2586,6 +2594,8 @@ EXPORT_SYMBOL(rproc_free); * * If no one holds any reference to rproc anymore, then its refcount would * now drop to zero, and it would be freed. + * + * Context: May sleep if this drops the last reference. */ void rproc_put(struct rproc *rproc) { diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c index d5e9ff045a28..ecc022e354db 100644 --- a/drivers/remoteproc/remoteproc_virtio.c +++ b/drivers/remoteproc/remoteproc_virtio.c @@ -23,6 +23,7 @@ #include <linux/err.h> #include <linux/kref.h> #include <linux/slab.h> +#include <linux/srcu.h> #include "remoteproc_internal.h" @@ -89,14 +90,19 @@ static bool rproc_virtio_notify(struct virtqueue *vq) irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid) { struct rproc_vring *rvring; + int srcu_idx; + irqreturn_t ret; + + srcu_idx = srcu_read_lock(&rproc->vq_srcu); dev_dbg(&rproc->dev, "vq index %d is interrupted\n", notifyid); rvring = idr_find(&rproc->notifyids, notifyid); - if (!rvring || !rvring->vq) - return IRQ_NONE; + ret = rvring && rvring->vq ? vring_interrupt(0, rvring->vq) : IRQ_NONE; + + srcu_read_unlock(&rproc->vq_srcu, srcu_idx); - return vring_interrupt(0, rvring->vq); + return ret; } EXPORT_SYMBOL(rproc_vq_interrupt); @@ -242,6 +248,13 @@ static void rproc_virtio_reset(struct virtio_device *vdev) dev_dbg(&vdev->dev, "reset !\n"); } +static void rproc_virtio_synchronize_cbs(struct virtio_device *vdev) +{ + struct rproc *rproc = vdev_to_rproc(vdev); + + synchronize_srcu(&rproc->vq_srcu); +} + /* provide the vdev features as retrieved from the firmware */ static u64 rproc_virtio_get_features(struct virtio_device *vdev) { @@ -330,6 +343,7 @@ static const struct virtio_config_ops rproc_virtio_config_ops = { .find_vqs = rproc_virtio_find_vqs, .del_vqs = rproc_virtio_del_vqs, .reset = rproc_virtio_reset, + .synchronize_cbs = rproc_virtio_synchronize_cbs, .set_status = rproc_virtio_set_status, .get_status = rproc_virtio_get_status, .get = rproc_virtio_get, diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c index de2af696de6c..4f9e70c1332e 100644 --- a/drivers/virtio/virtio_vdpa.c +++ b/drivers/virtio/virtio_vdpa.c @@ -27,6 +27,7 @@ struct virtio_vdpa_device { struct virtio_device vdev; struct vdpa_device *vdpa; + rwlock_t callback_lock; u64 features; }; @@ -123,8 +124,24 @@ static irqreturn_t virtio_vdpa_config_cb(void *private) static irqreturn_t virtio_vdpa_virtqueue_cb(void *private) { struct virtqueue *vq = private; + struct virtio_vdpa_device *vd_dev; + unsigned long flags; + irqreturn_t ret; - return vring_interrupt(0, vq); + vd_dev = to_virtio_vdpa_device(vq->vdev); + read_lock_irqsave(&vd_dev->callback_lock, flags); + ret = vring_interrupt(0, vq); + read_unlock_irqrestore(&vd_dev->callback_lock, flags); + + return ret; +} + +static void virtio_vdpa_synchronize_cbs(struct virtio_device *vdev) +{ + struct virtio_vdpa_device *vd_dev = to_virtio_vdpa_device(vdev); + + write_lock_irq(&vd_dev->callback_lock); + write_unlock_irq(&vd_dev->callback_lock); } static struct virtqueue * @@ -439,6 +456,7 @@ static const struct virtio_config_ops virtio_vdpa_config_ops = { .reset = virtio_vdpa_reset, .find_vqs = virtio_vdpa_find_vqs, .del_vqs = virtio_vdpa_del_vqs, + .synchronize_cbs = virtio_vdpa_synchronize_cbs, .get_features = virtio_vdpa_get_features, .finalize_features = virtio_vdpa_finalize_features, .bus_name = virtio_vdpa_bus_name, @@ -472,6 +490,7 @@ static int virtio_vdpa_probe(struct vdpa_device *vdpa) vd_dev->vdev.config = &virtio_vdpa_config_ops; vd_dev->vdev.map = vdpa->map; vd_dev->vdpa = vdpa; + rwlock_init(&vd_dev->callback_lock); vd_dev->vdev.id.device = ops->get_device_id(vdpa); if (vd_dev->vdev.id.device == 0) diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h index a44368737b39..ad6bccbdfabc 100644 --- a/include/linux/remoteproc.h +++ b/include/linux/remoteproc.h @@ -11,6 +11,7 @@ #include <linux/types.h> #include <linux/mutex.h> #include <linux/spinlock.h> +#include <linux/srcu.h> #include <linux/virtio.h> #include <linux/cdev.h> #include <linux/completion.h> @@ -230,6 +231,7 @@ enum rproc_features { * @rvdevs: list of remote virtio devices * @subdevs: list of subdevices, to following the running state * @notifyids: idr for dynamically assigning rproc-wide unique notify ids + * @vq_srcu: SRCU domain for virtqueue callbacks * @index: index of this rproc device * @attach_work: workqueue for attaching rproc * @crash_handler: workqueue for handling a crash @@ -276,6 +278,7 @@ struct rproc { struct list_head rvdevs; struct list_head subdevs; struct idr notifyids; + struct srcu_struct vq_srcu; int index; struct work_struct attach_work; struct work_struct crash_handler; -- 2.39.5 (Apple Git-154)
