Since the original virtio_find_vqs() is no longer present, rename
virtio_find_vqs_info() back to virtio_find_vqs().
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-20-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
All callers of virtio_find_vqs() and virtio_find_vqs_ctx() were
converted to use virtio_find_vqs_info(). Remove no longer used helpers.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-19-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Instead of passing separate names and callbacks arrays
to virtio_find_vqs(), have one of virtual_queue_info structs and
pass it to virtio_find_vqs_info().
Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-18-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Instead of passing separate names and callbacks arrays
to virtio_find_vqs(), have one of virtual_queue_info structs and
pass it to virtio_find_vqs_info().
Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-17-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Instead of passing separate names and callbacks arrays
to virtio_find_vqs(), allocate one of virtual_queue_info structs and
pass it to virtio_find_vqs_info().
Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-16-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Instead of passing separate names and callbacks arrays
to virtio_find_vqs(), allocate one of virtual_queue_info structs and
pass it to virtio_find_vqs_info().
Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-15-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Instead of passing separate names and callbacks arrays
to virtio_find_vqs_ctx(), allocate one of virtual_queue_info structs
and pass it to virtio_find_vqs_info().
Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-14-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Instead of passing separate names and callbacks arrays
to virtio_find_vqs(), allocate one of virtual_queue_info structs and
pass it to virtio_find_vqs_info().
Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-13-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Instead of passing separate names and callbacks arrays
to virtio_find_vqs(), allocate one of virtual_queue_info structs and
pass it to virtio_find_vqs_info().
Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-12-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Instead of passing separate names and callbacks arrays
to virtio_find_vqs(), allocate one of virtual_queue_info structs and
pass it to virtio_find_vqs_info().
Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-11-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Since the original find_vqs() is no longer present, rename
find_vqs_info() back to find_vqs().
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-10-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
As it is no longer used, remove it.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-9-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Since there are no more implementations of find_vqs() op, call
virtio_find_vqs_info() from virtio_find_single_vq() directly.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-8-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Convert existing find_vqs() transport implementations
to use find_vqs_info() config op.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-7-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Introduce a structure virtio_queue_info to carry name, callback and ctx
together. In order to allow config implementations to accept config op
with array of virtio_queue_info structures, introduce a new
find_vqs_info() op. Do the needed conversion in virtio_find_vqs_ctx().
Note that whole virtio_find_vqs_ctx() is going to be eventually removed
at the and of this patchset.
Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-5-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
In order to prepare for conversion of virtio_find_vqs*() arguments, make
virtio_find_single_vq() to call virtio_find_vqs() instead of
op directly.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-4-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
In order to prepare for conversion of virtio_find_vqs*() arguments, make
virtio_find_vqs() to call virtio_find_vqs_ctx() instead of op directly.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-3-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Since caif uses only one queue, convert to virtio_find_single_vq()
helper which is made for this purpose.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-2-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
VQ indices in the range [cur_num_qps, max_vqs) represent queues that
have not yet been activated. .set_vq_ready should not activate these
VQs.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-24-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The vdpa device can be reset many times in sequence without any
significant state changes in between. Previously this was not a problem:
VQs were torn down only on first reset. But after VQ pre-creation was
introduced, each reset will delete and re-create the hardware VQs and
their associated resources.
To solve this problem, avoid resetting hardware VQs if the VQs are still
in a blank state.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-23-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
There are a few conditions under which the hardware VQs need a full
teardown and setup:
- VQ size changed to something else than default value. Hardware VQ size
modification is not supported.
- User turns off certain device features: mergeable buffers, checksum
virtio 1.0 compliance. In these cases, the TIR and RQT need to be
re-created.
Add a needs_teardown configuration variable and set it when detecting
the above scenarios. On next DRIVER_OK, the resources will be torn down
first.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-22-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Currently, hardware VQs are created right when the vdpa device gets into
DRIVER_OK state. That is easier because most of the VQ state is known by
then.
This patch switches to creating all VQs and their associated resources
at device creation time. The motivation is to reduce the vdpa device
live migration downtime by moving the expensive operation of creating
all the hardware VQs and their associated resources out of downtime on
the destination VM.
The VQs are now created in a blank state. The VQ configuration will
happen later, on DRIVER_OK. Then the configuration will be applied when
the VQs are moved to the Ready state.
When .set_vq_ready() is called on a VQ before DRIVER_OK, special care is
needed: now that the VQ is already created a resume_vq() will be
triggered too early when no mr has been configured yet. Skip calling
resume_vq() in this case, let it be handled during DRIVER_OK.
For virtio-vdpa, the device configuration is done earlier during
.vdpa_dev_add() by vdpa_register_device(). Avoid calling
setup_vq_resources() a second time in that case.
On a 64 CPU, 256 GB VM with 1 vDPA device of 16 VQps, the full VQ
resource creation + resume time was ~370ms. Now it's down to 60 ms
(only VQ config and resume). The measurements were done on a ConnectX6DX
based vDPA device.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-21-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Resume a VQ if it is already created when the number of VQ pairs
increases. This is done in preparation for VQ pre-creation which is
coming in a later patch. It is necessary because calling setup_vq() on
an already created VQ will return early and will not enable the queue.
For symmetry, suspend a VQ instead of tearing it down when the number of
VQ pairs decreases. But only if the resume operation is supported.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-20-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
There are a few more places modifying the VQ to Ready directly. Let's
consolidate them into resume_vq().
The redundant warnings for resume_vq() errors can also be dropped.
There is one special case that needs to be handled for virtio-vdpa:
the initialized flag must be set to true earlier in setup_vq() so that
resume_vq() doesn't return early.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-18-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Instead of blindly calling suspend/resume_vqs(), make then return error
codes.
To keep compatibility, keep suspending or resuming VQs on error and
return the last error code. The assumption here is that the error code
would be the same.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-17-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Until now resume_vq() was used only for the suspend/resume scenario.
This change also allows calling resume_vq() to bring it from Init to
Ready state (VQ initialization).
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-16-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Based on the filled flag, create VQs that are filled or blank.
Blank VQs will be filled in later through VQ modify.
Downstream patches will make use of this to pre-create blank VQs at
vdpa device creation.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-15-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Otherwise, when virtqueues are moved from INIT to READY the latest mkey
will not be set appropriately.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-14-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Currently rqt_size is initialized during device flag configuration.
That's because it is the earliest moment when device knows if MQ
(multi queue) is on or off.
Shift this configuration earlier to device creation time. This implies
that non-MQ devices will have a larger RQT size. But the configuration
will still be correct.
This is done in preparation for the pre-creation of hardware virtqueues
at device add time. When that change will be added, RQT will be created
at device creation time so it needs to be initialized to its max size.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-13-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The virtqueue size is a pre-requisite for setting up any virtqueue
resources. For the upcoming optimization of creating virtqueues at
device add, the virtqueue size has to be configured.
The queue size check in setup_vq() will always be false. So remove it.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-12-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This is done in preparation for the pre-creation of hardware virtqueues
at device add time.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-11-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This is done in preparation for the pre-creation of hardware virtqueues
at device add time.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-10-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Function is used to set default values, so name it accordingly.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-9-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
The hardware VQ configuration is mirrored by data in struct
mlx5_vdpa_virtqueue . Instead of clearing just a few fields at reset,
fully clear the struct and initialize with the appropriate default
values.
As clear_vqs_ready() is used only during reset, get rid of it.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-8-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The virtio spec says that a vdpa device should start off with one queue
pair. The driver is already compliant.
This patch moves the initialization to device add and reset times. This
is done in preparation for the pre-creation of hardware virtqueues at
device add time.
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-7-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Use the dedicated suspend_vqs() function instead.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-6-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
No need to iterate over max number of VQs.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-5-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Originally, the second loop initialized the CVQ. But (acde392949
("vdpa/mlx5: Use consistent RQT size") initialized all the queues in the
first loop, so the second iteration in init_mvqs() is never called
because the first one will iterate up to max_vqs.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-3-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
setup_driver()/teardown_driver() are a bit vague. These functions are
used for virtqueue resources.
Same for alloc_resources()/teardown_resources(): they represent fixed
resources that are meant to exist during the device lifetime.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-1-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Currently, when the Virtio queue is full, a work item is scheduled
to execute in 1ms that retries adding the request to the queue.
This is a large amount of time on the scale on which a
virtio-fs device can operate. When using a DPU this is around
30-40us baseline without going to a remote server (4k, QD=1).
This patch changes the retrying behavior to immediately filling the
Virtio queue up again when a completion has been received.
This reduces the 99.9th percentile latencies in our tests by
60x and slightly increases the overall throughput, when using a
workload IO depth 2x the size of the Virtio queue and a
DPU-powered virtio-fs device (NVIDIA BlueField DPU).
Signed-off-by: Peter-Jan Gootzen <pgootzen@nvidia.com>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Yoray Zack <yorayz@nvidia.com>
Message-Id: <20240517190435.152096-3-pgootzen@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Currently, when the enqueueing of a request or forget operation fails
with -ENOMEM, the enqueueing is retried after a timeout. This patch
removes this behavior and treats -ENOMEM in these scenarios like any
other error. By bubbling up the error to user space in the case of a
request, and by dropping the operation in case of a forget. This
behavior matches that of the FUSE layer above, and also simplifies the
error handling. The latter will come in handy for upcoming patches that
optimize the retrying of operations in case of -ENOSPC.
Signed-off-by: Peter-Jan Gootzen <pgootzen@nvidia.com>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Yoray Zack <yorayz@nvidia.com>
Message-Id: <20240517190435.152096-2-pgootzen@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
With ARCH=x86, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/vdpa/vdpa.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/vdpa/ifcvf/ifcvf.o
Add the missing invocations of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Message-Id: <20240611-md-drivers-vdpa-v1-1-efaf2de15152@quicinc.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
With ARCH=sh, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/virtio/virtio.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/virtio/virtio_ring.o
Add the missing invocations of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Message-Id: <20240702-md-sh-drivers-virtio-v1-1-cf7325ab6ccc@quicinc.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Fix the allmodconfig 'make w=1' issue:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/vhost/vringh.o
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Message-Id: <20240516-md-vringh-v1-1-31bf37779a5a@quicinc.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
This commit changes lingshan's email from intel.com
to kernel.org.
Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Message-Id: <20240514165125.74802-1-lingshan.zhu@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
All callers of vhost_get_avail_idx() use smp_rmb() to
order the available ring entry read and avail_idx read.
Make vhost_get_avail_idx() call smp_rmb() itself whenever the avail_idx
is accessed. This way, the callers don't need to worry about the memory
barrier. As a side benefit, we also validate the index on all paths now,
which will hopefully help prevent/catch earlier future bugs.
Note that current code is inconsistent in how the errors are handled.
They are treated as an empty ring in some places, but as non-empty
ring in other places. This patch doesn't attempt to change the existing
behaviour.
No functional change intended.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Message-Id: <20240429232748.642356-1-gshan@redhat.com>
