iommu/amd: Drop the lock while allocating new irq remap table

Browse source

The irq_remap_table is allocated while the iommu_table_lock is held with
interrupts disabled.
>From looking at the call sites, all callers are in the early device
initialisation (apic_bsp_setup(), pci_enable_device(),
pci_enable_msi()) so make sense to drop the lock which also enables
interrupts and try to allocate that memory with GFP_KERNEL instead
GFP_ATOMIC.

Since during the allocation the iommu_table_lock is dropped, we need to
recheck if table exists after the lock has been reacquired. I *think*
that it is impossible that the "devid" entry appears in irq_lookup_table
while the lock is dropped since the same device can only be probed once.
However I check for both cases, just to be sure.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

...

This commit is contained in:

Sebastian Andrzej Siewior 2018-03-22 16:22:40 +01:00 • committed by Joerg Roedel

parent 2fcc1e8ac4

commit 993ca6e063

1 changed files with 45 additions and 18 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

65

drivers/iommu/amd_iommu.c

View file