The cxlflash driver supports performing a write-same16 to scrub virtual
luns when they are released by a user. To date, AFUs for adapters that
are supported by cxlflash do not have the capability to unmap as part of
the WS operation. This can lead to fragmented flash devices which results
in performance degradation.
Future AFUs can optionally support unmap write-same commands and reflects
this support via the context control register. This provides userspace
applications with direct visibility such that they need not depend on a
host API.
Detect unmap support during cxlflash initialization by reading the context
control register associated with the primary hardware queue. Update the
existing write_same16() routine to set the unmap bit in the CDB when unmap
is supported by the host.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
AFU sync operations are not currently evaluated for failure. This is
acceptable for paths where there is not a dependency on the AFU being
consistent with the host. Examples include link reset events and LUN
cleanup operations. On paths where there is a dependency, such as a LUN
open, a sync failure should be acted upon.
In the event of AFU sync failures, either log or cleanup as appropriate for
operations that are dependent on a successful sync completion.
Update documentation to reflect behavior in the event of an AFU sync
failure.
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
As staging to support FC-related updates to the SISlite specification,
introduce helper routines to obtain references to FC resources that exist
within the global map. This will allow changes to the underlying global map
structure without impacting existing code paths.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
At present, the cxlflash driver only supports hardware with two FC ports. The
code was initially designed with this assumption and is dependent on having
two FC ports - adding more ports will break logic within the driver.
To mitigate this issue, remove the existing port assumptions and transition
the code to support more than two ports. As a side effect, clarify the
interpretation of the DK_CXLFLASH_ALL_PORTS_ACTIVE flag.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
All but one caller want the decoded sense header, so offer the existing
__scsi_execute helper as the public scsi_execute API to simply the
callers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The usage of prints within the cxlflash driver is inconsistent. This
hinders debug and makes the driver source and log output appear sloppy.
The following cleanups help unify the prints within cxlflash:
- move all prints to dev-* where possible
- transition all hex prints to lowercase
- standardize variable prints in debug output
- derive pointers in a consistent manner
- change int to bool where appropriate
- remove superfluous data from prints and print statements that do not
make sense
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Caching the adapter file descriptor and performing a close on behalf of
an application is a poor design. This is due to the fact that once a
file descriptor in installed, it is free to be altered without the
knowledge of the cxlflash driver. This can lead to inconsistencies
between the application and kernel. Furthermore, the nature of the
former design is more exploitable and thus should be abandoned.
To support applications performing a close on the adapter file that is
associated with a context, a new flag is introduced to the user API to
indicate to applications that they are responsible for the close
following the cleanup (detach) of a context. The documentation is also
updated to reflect this change in behavior.
Inspired-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Acked-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Applications which use virtual LUN's that are backed by a physical LUN
over both adapter ports may experience an I/O failure in the event of a
link loss (e.g. cable pull).
Virtual LUNs may be accessed through one or both ports of the adapter.
This access is encoded in the translation entries that comprise the
virtual LUN and used by the AFU for load-balancing I/O and handling
failover scenarios. In a link loss scenario, even though the AFU is able
to maintain connectivity to the LUN, it is up to the application to
retry the failed I/O. When applications are unaware of the virtual LUN's
underlying topology, they are unable to make a sound decision of when to
retry an I/O and therefore are forced to make their reaction to a failed
I/O absolute. The result is either a failure to retry I/O or increased
latency for scenarios where a retry is pointless.
To remedy this scenario, provide feedback back to the application on
virtual LUN creation as to which ports the LUN may be accessed. LUN's
spanning both ports are candidates for a retry in a presence of an I/O
failure.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Acked-by: Manoj Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Ioctl threads that use scsi_execute() can run for an excessive amount
of time due to the fact that they have lengthy timeouts and retry logic
built in. Under normal operation this is not an issue. However, once EEH
enters the picture, a long execution time coupled with the possibility
that a timeout can trigger entry to the driver via registered reset
callbacks becomes a liability.
In particular, a deadlock can occur when an EEH event is encountered
while in running in scsi_execute(). As part of the recovery, the EEH
handler drains all currently running ioctls, waiting until they have
completed before proceeding with a reset. As the scsi_execute()'s are
situated on the ioctl path, the EEH handler will wait until they (and
the remainder of the ioctl handler they're associated with) have
completed. Normally this would not be much of an issue aside from the
longer recovery period. Unfortunately, the scsi_execute() triggers a
reset when it times out. The reset handler will see that the device is
already being reset and wait until that reset completed. This creates
a condition where the EEH handler becomes stuck, infinitely waiting for
the ioctl thread to complete.
To avoid this behavior, temporarily unmark the scsi_execute() threads
as an ioctl thread by releasing the ioctl read semaphore. This allows
the EEH handler to proceed with a recovery while the thread is still
running. Once the scsi_execute() returns, the ioctl read semaphore is
reacquired and the adapter state is rechecked in case it changed while
inside of scsi_execute(). The state check will wait if the adapter is
still being recovered or returns a failure if the recovery failed. In
the event that the adapter reset failed, the failure is simply returned
as the ioctl would be unable to continue.
Reported-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
There are several spelling and grammar mistakes throughout the
driver. Additionally there are a handful of places where there
are extra lines and unnecessary variables/statements. These are
a nuisance and pollute the driver.
Fix spelling and grammar issues. Update some comments for clarity and
consistency. Remove extra lines and a few unneeded variables/statements.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
Sparse uncovered several errors with MMIO operations (accessing
directly) and handling endianness. These can cause issues when
running in different environments.
Introduce __iomem and proper endianness tags/swaps where
appropriate to make driver sparse clean.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
If the same virtual LUN is accessed over multiple cards, only accesses
made over the first card will be valid. Accesses made over the second
card will go to the wrong LUN causing data corruption.
This is because the global LUN's mode word was being used to determine
whether the LUN table for that card needs to be programmed. The mode
word would be setup by the first card, causing the LUN table for the
second card to not be programmed.
By unconditionally initializing the LUN table (not depending on the
mode word), the problem is avoided.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
The timeout value for read capacity is too small. Certain devices
may take longer to respond and thus the command may prematurely
timeout. Additionally the literal used for the timeout is stale.
Update the timeout to 30 seconds (matches the value used in sd.c)
and rework the timeout literal to a more appropriate description.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
Magic numbers are not meaningful and can create confusion. As a
remedy, replace them with descriptive literals.
Replace 512 with literal MAX_SECTOR_UNIT.
Replace 5 with literal CMD_RETRIES.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
Add support for physical LUN segmentation (virtual LUNs) to device
driver supporting the IBM CXL Flash adapter. This patch allows user
space applications to virtually segment a physical LUN into N virtual
LUNs, taking advantage of the translation features provided by this
adapter.
Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Michael Neuling <mikey@neuling.org>
Reviewed-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
