This is another attempt to implement an acceptable implementation of async device shutdown, inspired by a previous attempt by Tanjore Suresh. For systems with many disks, async shutdown can greatly reduce shutdown times from having slow operations run in parallel. The older patches were rejected, with this new implementation attempting to fix my understanding of the flaws in the older patches. Using similar interfaces and building off the ideas of the older patches, this patchset creates an async shutdown implementation which follows the basic ordering of the shutdown list, ensuring the shutdown of any children devices complete whether synchronous or asynchronous before performing shutdown on a parent device. In addition to an implementation for asynchronous pci nvme shutdown, this patchset also adds support for async shutdown of sd devices for cache flush. As an example of the effects of the patch, one system with a large amount of disks went from over 30 seconds to shut down to less than 5. The specific driver changes are the roughest part of this patchset. But the acceptability of the core async functionality is critical. Any feedback on flaws or improvements is appreciated. David Jeffery (6): minimal async shutdown infrastructure Improve ability to perform async shutdown in parallel pci bus async shutdown support pci nvme async shutdown support scsi mid layer support for async command submit sd: async cache flush on shutdown drivers/base/base.h | 1 + drivers/base/core.c | 149 +++++++++++++++++++++++++++++++++- drivers/nvme/host/core.c | 26 ++++-- drivers/nvme/host/nvme.h | 2 + drivers/nvme/host/pci.c | 53 +++++++++++- drivers/pci/pci-driver.c | 24 +++++- drivers/scsi/scsi_lib.c | 138 ++++++++++++++++++++++++------- drivers/scsi/sd.c | 66 +++++++++++++-- drivers/scsi/sd.h | 2 + include/linux/device/bus.h | 8 +- include/linux/device/driver.h | 7 ++ include/linux/pci.h | 4 + include/scsi/scsi_device.h | 8 ++ 13 files changed, 439 insertions(+), 49 deletions(-) -- 2.43.0
