mbox series

[v2,00/13] cpumask: cleanup cpumask_next_wrap() implementation and usage

Message ID 20250128164646.4009-1-yury.norov@gmail.com
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Series cpumask: cleanup cpumask_next_wrap() implementation and usage | expand

Message

Yury Norov Jan. 28, 2025, 4:46 p.m. UTC 
cpumask_next_wrap() is overly complicated, comparing to it's generic
version find_next_bit_wrap(), not mentioning it duplicates the above.
It roots to the times when the function was used in the implementation
of for_each_cpu_wrap() iterator. The function has 2 additional parameters
that were used to catch loop termination condition for the iterator.
(Although, only one is needed.)

Since 4fe49b3b97c262 ("lib/bitmap: introduce for_each_set_bit_wrap()
macro"), for_each_cpu_wrap() is wired to corresponding generic
wrapping bitmap iterator, and additional complexity of
cpumask_next_wrap() is not needed anymore.

All existing users call cpumask_next_wrap() in a manner that makes
it possible to turn it to a straight and simple alias to
find_next_bit_wrap().

This series replaces historical 4-parameter cpumask_next_wrap() with a
thin 2-parameter wrapper around find_next_bit_wrap().

Where it's possible to use for_each_cpu_wrap() iterator, the code is
switched to use it because it's always preferable to use iterators over
open loops.

This series touches various scattered subsystems and To-list for the
whole series is quite a long. To minimize noise, I send cover-letter and
key patches #5 and 6 to every person involved. All other patches are sent
individually to those pointed by scripts/get_maintainers.pl.

I'd like to move the series with my bitmap-for-next branch as a whole.

v1: https://lore.kernel.org/netdev/20241228184949.31582-1-yury.norov@gmail.com/T/
v2:
 - rebase on top of today's origin/master;
 - drop #v1-10: not needed since v6.14 @ Sagi Grinberg;
 - #2, #3: fix picking next unused CPU @ Nick Child;
 - fix typos, cleanup comments @ Bjorn Helgaas, Alexander Gordeev;
 - CC Christoph Hellwig for the whole series.

Yury Norov (13):
  objpool: rework objpool_pop()
  virtio_net: simplify virtnet_set_affinity()
  ibmvnic: simplify ibmvnic_set_queue_affinity()
  powerpc/xmon: simplify xmon_batch_next_cpu()
  cpumask: deprecate cpumask_next_wrap()
  cpumask: re-introduce cpumask_next{,_and}_wrap()
  cpumask: use cpumask_next_wrap() where appropriate
  padata: switch padata_find_next() to using cpumask_next_wrap()
  s390: switch stop_machine_yield() to using cpumask_next_wrap()
  scsi: lpfc: switch lpfc_irq_rebalance() to using cpumask_next_wrap()
  scsi: lpfc: rework lpfc_next_{online,present}_cpu()
  PCI: hv: Switch hv_compose_multi_msi_req_get_cpu() to using
    cpumask_next_wrap()
  cpumask: drop cpumask_next_wrap_old()

 arch/powerpc/xmon/xmon.c            |  6 +--
 arch/s390/kernel/processor.c        |  2 +-
 drivers/net/ethernet/ibm/ibmvnic.c  | 18 +++++---
 drivers/net/virtio_net.c            | 12 ++---
 drivers/pci/controller/pci-hyperv.c |  3 +-
 drivers/scsi/lpfc/lpfc.h            | 23 +++-------
 drivers/scsi/lpfc/lpfc_init.c       |  2 +-
 include/linux/cpumask.h             | 69 ++++++++++++++++++++---------
 include/linux/objpool.h             |  7 ++-
 kernel/padata.c                     |  2 +-
 lib/cpumask.c                       | 37 +---------------
 11 files changed, 81 insertions(+), 100 deletions(-)