When the user's login time is newer than the cache's timestamp,
the original entry in the RB-tree will be replaced by a new entry.
Currently, the timestamp is only set if the entry is not found in
the RB-tree, which can cause the timestamp to be undefined when
the entry exists. This may result in a significant increase in
ACCESS operations if the timestamp is set to zero.
Signed-off-by: Chengen Du <email address hidden>
Fixes: 0eb43812c027 ("NFS: Clear the file access cache upon login”)
Reviewed-by: Benjamin Coddington <email address hidden>
Signed-off-by: Anna Schumaker <email address hidden>
(back-ported from commit 21fd9e8700de86d1169f6336e97d7a74916ed04a linux-next)
Signed-off-by: Chengen Du <email address hidden>
Acked-by: Dimitri John Ledkov <email address hidden>
Acked-by: Kleber Sacilotto de Souza <email address hidden>
Signed-off-by: Kleber Sacilotto de Souza <email address hidden>
Signed-off-by: Brad Figg <email address hidden>
To save the vgic LPI pending state with GICv4.1, the VPEs must all be
unmapped from the ITSs so that the sGIC caches can be flushed.
The opposite is done once the state is saved.
This is all done by using the activate/deactivate irqdomain callbacks
directly from the vgic code. Crutially, this is done without holding
the irqdesc lock for the interrupts that represent the VPE. And these
callbacks are changing the state of the irqdesc. What could possibly
go wrong?
If a doorbell fires while we are messing with the irqdesc state,
it will acquire the lock and change the interrupt state concurrently.
Since we don't hole the lock, curruption occurs in on the interrupt
state. Oh well.
While acquiring the lock would fix this (and this was Shanker's
initial approach), this is still a layering violation we could do
without. A better approach is actually to free the VPE interrupt,
do what we have to do, and re-request it.
It is more work, but this usually happens only once in the lifetime
of the VM and we don't really care about this sort of overhead.
Fixes: f66b7b151e00 ("KVM: arm64: GICv4.1: Try to save VLPI state in save_pending_tables")
Reported-by: Shanker Donthineni <email address hidden>
Signed-off-by: Marc Zyngier <email address hidden>
Cc: <email address hidden>
Link: https://<email address hidden>
Signed-off-by: Shanker Donthineni <email address hidden>
Acked-by: Brad Figg <email address hidden>
Acked-by: Ian May <email address hidden>
Acked-by: Jacob Martin <email address hidden>
Signed-off-by: Brad Figg <email address hidden>
