[PATCH v3 0/2] libsas: rediscover improvements for linkrate/sas_addr changes

[Xingui Yang <yangxingui@huawei.com>]

When a device attached to an expander phy experiences a linkrate change
(e.g., due to cable reconnection or negotiation), the current code in
sas_rediscover_dev() treats it as "broadcast flutter" and takes no action
if the SAS address and device type remain unchanged.

This series is a new version based on John Garry's suggestion [1] to
check the linkrate and mark the device as gone and rediscover when
flutter occurs, replacing the previous v2 patch series that used lldd
callbacks.

The previous v2 approach added lldd_dev_info_update callback which John
commented as "seem fragile and too specialized" [2]. This v3 series adopts
a simpler approach that directly checks linkrate/sas_addr changes in
sas_rediscover_dev() and triggers rediscovery using libsas's standard
async discovery pattern.

This aligns with Jason Yan's earlier work [3] which was verified to
solve the linkrate change issue.

Changes from v2:
- Drop lldd_dev_info_update callback approach per John Garry's suggestion
- Drop hisi_sas specific changes (no longer needed without callback)
- Use libsas's async discovery pattern for rediscovery
- Add sas_addr change detection alongside linkrate change

[1] https://lore.kernel.org/linux-scsi/c4e4c99f-a13c-4e28-8650-48be1f96d7cf@oracle.com/
[2] https://lore.kernel.org/linux-scsi/28bd9d5b-f597-0aae-5340-bd951b2083aa@huawei.com/
[3] https://lore.kernel.org/linux-scsi/20190130082412.9357-6-yanaijie@huawei.com/

Your Name (2):
  scsi: libsas: refactor sas_ex_to_ata() using new helper
    sas_ex_to_dev()
  scsi: libsas: Add linkrate and sas_addr change detection in rediscover

 drivers/scsi/libsas/sas_expander.c | 44 ++++++++++++++++++++++++------
 drivers/scsi/libsas/sas_internal.h |  1 +
 2 files changed, 37 insertions(+), 8 deletions(-)

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2.43.0