fbnic: Add additional handling of IRQs

We have two issues that need to be addressed in our IRQ handling.

One is the fact that we can end up double-freeing IRQs in the event of an
exception handling error such as a PCIe reset/recovery that fails. To
prevent that from becoming an issue we can use the msix_vector values to
indicate that we have successfully requested/freed the IRQ by only setting
or clearing them when we have completed the given action.

The other issue is that we have several potential races in our IRQ path due
to us manipulating the mask before the vector has been truly disabled. In
order to handle that in the case of the FW mailbox we need to not
auto-enable the IRQ and instead will be enabling/disabling it separately.
In the case of the PCS vector we can mitigate this by unmapping it and
synchronizing the IRQ before we clear the mask.

The general order of operations after this change is now to request the
interrupt, poll the FW mailbox to ready, and then enable the interrupt. For
the shutdown we do the reverse where we disable the interrupt, flush any
pending Tx, and then free the IRQ. I am renaming the enable/disable to
request/free to be equivilent with the IRQ calls being used. We may see
additions in the future to enable/disable the IRQs versus request/free them
for certain use cases.

Fixes: da3cde08209e ("eth: fbnic: Add FW communication mechanism")
Fixes: 69684376eed5 ("eth: fbnic: Add link detection")
Signed-off-by: Alexander Duyck <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Reviewed-by: Jacob Keller <[email protected]>
Link: https://patch.msgid.link/174654719271.499179.3634535105127848325.stgit@ahduyck-xeon-server.home.arpa
Reviewed-by: Jakub Kicinski <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>

0 files changed, 0 insertions, 0 deletions