mainlining shenanigans
512857a795
If a SCSI device is deleted during scsi_eh host reset, we cannot get a
reference to the SCSI device anymore since scsi_device_get returns !=0 by
design. Assuming the recovery of adapter and port(s) was successful,
zfcp_erp_strategy_followup_success() attempts to trigger a LUN reset for the
half-gone SCSI device. Unfortunately, it causes the following confusing
trace record which states that zfcp will do a LUN recovery as "ERP need" is
ZFCP_ERP_ACTION_REOPEN_LUN == 1 and equals "ERP want".
Old example trace record formatted with zfcpdbf from s390-tools:
Tag: : ersfs_3 ERP, trigger, unit reopen, port reopen succeeded
LUN : 0x<FCP_LUN>
WWPN : 0x<WWPN>
D_ID : 0x<N_Port-ID>
Adapter status : 0x5400050b
Port status : 0x54000001
LUN status : 0x40000000 ZFCP_STATUS_COMMON_RUNNING
but not ZFCP_STATUS_COMMON_UNBLOCKED as it
was closed on close part of adapter reopen
ERP want : 0x01
ERP need : 0x01 misleading
However, zfcp_erp_setup_act() returns NULL as it cannot get the reference.
Hence, zfcp_erp_action_enqueue() takes an early goto out and _NO_ recovery
actually happens.
We always do want the recovery trigger trace record even if no erp_action
could be enqueued as in this case. For other cases where we did not enqueue
an erp_action, 'need' has always been zero to indicate this. In order to
indicate above goto out, introduce an eyecatcher "flag" to mark the "ERP
need" as 'not needed' but still keep the information which erp_action type,
that zfcp_erp_required_act() had decided upon, is needed. 0xc_ is chosen to
be visibly different from 0x0_ in "ERP want".
New example trace record formatted with zfcpdbf from s390-tools:
Tag: : ersfs_3 ERP, trigger, unit reopen, port reopen succeeded
LUN : 0x<FCP_LUN>
WWPN : 0x<WWPN>
D_ID : 0x<N_Port-ID>
Adapter status : 0x5400050b
Port status : 0x54000001
LUN status : 0x40000000
ERP want : 0x01
ERP need : 0xc1 would need LUN ERP, but no action set up
^
Before v2.6.38 commit
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.