On Thu, Nov 23, 2023 at 02:49:27PM -0500, Stefan Hajnoczi wrote: > The SCSI subsystem uses the AioContext lock to protect internal state. This is > necessary because the main loop and the IOThread can access SCSI state in > parallel. This inter-thread access happens during scsi_device_purge_requests() > and scsi_dma_restart_cb(). > > This patch series modifies the code so SCSI state is only accessed from the > IOThread that is executing requests. Once this has been achieved the > AioContext > lock is no longer necessary. > > Note that a few aio_context_acquire()/aio_context_release() calls still remain > after this series. They surround API calls that invoke AIO_WAIT_WHILE() and > therefore still rely on the AioContext lock for now. > > Stefan Hajnoczi (4): > scsi: only access SCSIDevice->requests from one thread > virtio-scsi: don't lock AioContext around > virtio_queue_aio_attach_host_notifier() > scsi: don't lock AioContext in I/O code path > dma-helpers: don't lock AioContext in dma_blk_cb() > > include/hw/scsi/scsi.h | 7 +- > hw/scsi/scsi-bus.c | 174 ++++++++++++++++++++++---------- > hw/scsi/scsi-disk.c | 23 ----- > hw/scsi/scsi-generic.c | 20 +--- > hw/scsi/virtio-scsi-dataplane.c | 8 +- > system/dma-helpers.c | 7 +- > 6 files changed, 130 insertions(+), 109 deletions(-)
CCing Kevin and qemu-block > > -- > 2.42.0 >
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