[PATCH v5 0/3] SCSI: Fix issues between removing device and error handle

[Wenchao Hao]

2 issues are triggered because devices in removing would be skipped
when calling shost_for_each_device(), these issues are mainly in error
recovery path, which are:

1. statistic info printed at beginning of scsi_error_handler is wrong;
2. device reset is not triggered. drivers like smartpqi only implement
   eh_device_reset_handler, if device reset is skipped, the commands
   which had been sent to firmware or devices hardware are not cleared.
   The error handle would flush all these commands in scsi_unjam_host().
   When the commands are finished by hardware, use after free issue is
   triggered.
   The issue first happened with smartpqi devices, and can be reproduced
   with scsi_debug. I did not see any description about SDEV_DEL state
   can not perform device, so this is should be addressed.

A new macro shost_for_each_device_include_deleted() is added to address
these issues. The newly added macro would not skip scsi_device which is
in removing when iterate host's scsi_device and is called when statistic
host's error info and trying to reset scsi_device in error recovery path.

V5:
 - Rewrite cover letter and add fixes tag to each patch

V4:
 - Remove the forth patch which fix IO hang when device removing
   becaust the issue is fixed by commit '6df0e077d76bd (scsi: core:
   Kick the requeue list after inserting when flushing)'

V3:
  - Update patch description
  - Update comments of functions added

V2:
  - Fix IO hang by run all devices' queue after error handler
  - Do not modify shost_for_each_device() directly but add a new
    helper to iterate devices but do not skip devices in removing

Wenchao Hao (3):
  scsi: core: Add new helper to iterate all devices of host
  scsi: scsi_error: Fix wrong statistic when print error info
  scsi: scsi_error: Fix device reset is not triggered

 drivers/scsi/scsi.c        | 46 ++++++++++++++++++++++++++------------
 drivers/scsi/scsi_error.c  |  4 ++--
 include/scsi/scsi_device.h | 25 ++++++++++++++++++---
 3 files changed, 56 insertions(+), 19 deletions(-)

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2.38.1