enhance dmaengine core to support DMA device hotplug
Quoted 12 lines · Jiang Liu
Quoted 10 lines
From: Jiang Liu <liuj97@xxxxxxxxx>
This patchset tries to enhance the dmaengine and its clients to support hot-removal of DMA devices at runtime, especially for IOAT devices.
When hot-removing IOH (PCI host bridge) on Intel Nehalem/Westmere platform, we need to remove all IOAT devices embedded in the IOH. For future Intel processor with IIO (Embedded IOH), we need to remove IOAT devices even when hot-removing a physical processor. But current dmaengine implementation doesn't support hot-removal of IOAT devices at runtime.
Quoted 4 lines
Removal of the host bridge means several devices disappear at once. Is it safe to assume that this action is coordinated by userspace? I.e. is the kernel given a chance to shut everything down and remove drivers, or is this a "surprise" unplug?
Hi Dan,
Sorry for late reply! I just noticed this mail by browsing the linux-pci
mail list web archive just now.
Yes, it will be coordinated by user/kernel hotplug manager. We don't
plan to support surprisingly removal yet. It seems a little craze to support that.
Thanks!
Gerry