Messages in this thread | | | Date | Wed, 5 Dec 2018 16:50:12 +0100 | From | Joerg Roedel <> | Subject | Re: [PATCH v5 02/12] iommu/vt-d: Manage scalalble mode PASID tables |
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On Tue, Dec 04, 2018 at 01:58:06PM +0800, Lu Baolu wrote: > This function is called in an unsleepable context. > > spin_lock(&lock) > [...] > if (pasid_table_is_necessary) > allocate_pasid_table(dev) > [...] > spin_unlock(&lock) > > We can move it out of the lock range. > > How about > > if (pasid_table_is_necessary) > pasid_table = allocate_pasid_table(dev) > > spin_lock(&lock) > [...] > if (pasid_table_is_necessary) > set_up_pasid_table(pasid_table) > [...] > spin_unlock(&lock)
Hmm, so when the IOMMU is configured in scalable mode we can just allocate a pasid-table for the device when we set it up, right?
Scalable mode is a boot-time decision, so we know for sure whether we need a pasid-table on device-setup time. And the device-setup code it preemptable, so I think it this allocation should be outside of any spin-locked section.
Joerg
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