scsi: fcoe: Add a local_lock to fcoe_percpu

fcoe_get_paged_crc_eof() relies on the caller having preemption disabled to
ensure the per-CPU fcoe_percpu context remains valid throughout the
call. This is done by either holding spinlocks (such as bnx2fc_global_lock
or qedf_global_lock) or the get_cpu() from fcoe_alloc_paged_crc_eof(). This
last one breaks PREEMPT_RT semantics as there can be memory allocation and
end up sleeping in atomic contexts.

Introduce a local_lock_t to struct fcoe_percpu that will keep the non-RT
case the same, mapping to preempt_disable/enable, while RT will use a
per-CPU spinlock allowing the region to be preemptible but still maintain
CPU locality. The other users of fcoe_percpu are already safe in this
regard and do not require local_lock()ing.

Link: https://lore.kernel.org/r/[email protected]
Link: https://lore.kernel.org/r/[email protected]
Acked-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Davidlohr Bueso <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

0 files changed, 0 insertions, 0 deletions