shutdown_post_sync event. For adashutdown, this causes problems
because we need to poll for completion of the commands, but we're not
yet officially dumping yet, so the code from r326964 assumed we could
use the interrupt-driven commands rather than the polled ones. This
lead to a hang. Prevent this by also checking to see if the scheduler
is stopped to do the polling.
Reported by: markj@
Sponsored by: Netflix
Differential Review: https://reviews.freebsd.org/D13845
from the ada and da dump routines. This avoids difficult locking
problems from needing to be handled. While it might seem like this
would leave the periphs unprotected during dump, they were aleady
at risk of unexpected removal due to the dump functions not
keeping refcount state across the many calls that come in during
a dump. This is an exercise for future work.
Obtained from: Netflix
changed worked to capture dumps for me. However, the test for
SCHEDULER_STOPPED() isn't right. We can also call the dump routine
from ddb, in which case the scheduler is still running. This leads to
an assertion panic that we're sleeping when we shouldn't. Instead, use
the proper test for dumping or not. This brings us in line with other
places that do special things while we're doing polled I/O like this.
Noticed by: pho@
Differential Revision: https://reviews.freebsd.org/D13531
This provides a nice wrarpper around the XPT_PATH_INQ ccb creation and
calling.
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D13387
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
the IO type (Admin or NVM) using XPT op-codes XPT_NVME_ADMIN or
XPT_NVME_IO.
Submitted by: Chuck Tuffli <chuck@tuffli.net>
Differential Revision: https://reviews.freebsd.org/D10247
Implement the MMC/SD/SDIO protocol within a CAM framework. CAM's
flexible queueing will make it easier to write non-storage drivers
than the legacy stack. SDIO drivers from both the kernel and as
userland daemons are possible, though much of that functionality will
come later.
Some of the CAM integration isn't complete (there are sleeps in the
device probe state machine, for example), but those minor issues can
be improved in-tree more easily than out of tree and shouldn't gate
progress on other fronts. Appologies to reviews if specific items
have been overlooked.
Submitted by: Ilya Bakulin
Reviewed by: emaste, imp, mav, adrian, ian
Differential Review: https://reviews.freebsd.org/D4761
merge with first commit, various compile hacks.
If a peripheral driver (e.g. da, sa, cd) is added or removed from the
peripheral driver list while an unrelated peripheral driver instance (e.g.
da0, sa5, cd2) is going away and is inside camperiphfree(), we could
dereference an invalid pointer.
When peripheral drivers are added or removed (see periphdriver_register()
and periphdriver_unregister()), the peripheral driver array is resized
and existing entries are moved.
Although we hold the topology lock while we traverse the peripheral driver
list, we retain a pointer to the location of the peripheral driver pointer
and then drop the topology lock. So we are still vulnerable to the list
getting moved around while the lock is dropped.
To solve the problem, cache a copy of the peripheral driver pointer. If
its storage location in the list changes while we have the lock dropped, it
won't have any effect.
This doesn't solve the issue that peripheral drivers ("da", "cd", as opposed
to individual instances like "da0", "cd0") are not generally part of a
reference counting scheme to guard against deregistering them while there
are instances active. The caller (generally the person unloading a module)
has to be aware of active drivers and not unload something that is in use.
sys/cam/cam_periph.c:
In camperiphfree(), cache a pointer to the peripheral driver
instance to avoid holding a pointer to an invalid memory location
in the event that the peripheral driver list changes while we have
the topology lock dropped.
PR: kern/219701
Submitted by: avg
MFC after: 3 days
Sponsored by: Spectra Logic
using a driver-supplied sbuf for printing device discovery
announcements. This helps ensure that messages to the console
will be properly serialized (through sbuf_putbuf) and not be
truncated and interleaved with other messages. The
infrastructure mirrors the existing xpt_announce_periph()
entry point and is opt-in for now. No content or formatting
changes are visible to the operator other than the new coherency.
While here, eliminate the stack usage of the temporary
announcement buffer in some of the drivers. It's moved to the
softc for now, but future work will eliminate it entirely by
making the code flow more linear. Future work will also address
locking so that the sbufs can be dynamically sized.
The scsi_da, scs_cd, scsi_ses, and ata_da drivers are converted
at this point, other drivers can be converted at a later date.
A tunable+sysctl, kern.cam.announce_nosbuf, exists for testing
purposes but will be removed later.
TODO:
Eliminate all of the code duplication and temporary buffers. The
old printf-based methods will be retired, and xpt_announce_periph()
will just be a wrapper that uses a dynamically sized sbuf. This
requires that the register and deregister paths be made malloc-safe,
which they aren't currently.
Sponsored by: Netflix
For now it allows to unload CTL kernel module if there are no target-capable
SIMs in CAM. As next step full teardown of CAM targets can be implemented.
Upstream the BUF_TRACKING and FULL_BUF_TRACKING buffer debugging code.
This can be handy in tracking down what code touched hung bios and bufs
last. The full history is especially useful, but adds enough bloat that
it shouldn't be enabled in release builds.
Function names (or arbitrary string constants) are tracked in a
fixed-size ring in bufs. Bios gain a pointer to the upper buf for
tracking. SCSI CCBs gain a pointer to the upper bio for tracking.
Reviewed by: markj
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D8366
In cam_periph_runccb, cam_periph_ccbwait was using the value of the ccb
pinfo.index and status fields to determine whether the ccb was done,
but these fields are updated without a contending lock and could glitch
into states that would be erroneously interpreted as done. Instead,
have cam_periph_ccbwait look for the explicit result of the function
cam_periph_done.
Submitted by: Ryan Libby <rlibby@gmail.com>
Reviewed by: mav
MFC after: 3 weeks
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D8020
Some statuses, such as "ATA pass through information available", are part
part of absolutely normal operation and do not worth reporting.
MFC after: 2 weeks
transactions, but that value isn't used. It's bogusly used to report
in devstat, due to a cut and paste error from SCSI. Mark it as unused
in cam_fill_ataio. Reclaim the memory as a new ata_flags. In addition,
tag_id and init_id are completely unused, so reclaim those as 'unused'
now too. These were needlessly copied when ata was split from scsi.
This allows us, in the future, to create structures that can
communicate AUXILIARY regsiter to the SIMs, which cannot be done now.
Differential Revision: https://reviews.freebsd.org/D5598
periph level. When a relevant error is reported to the periph, some
amplifying information is gathered, and the error and information are fed
to devctl with the attributes / keys system=CAM, subsystem=periph. The
'type' key will be either 'error' or 'timeout', and based on this, various
other keys are also populated.
The purpose of this is to provide a concise mechanism for error reporting
that is less noisy than the system console but higher in resolution and
fidelity than simple sysctl counters. We will be using it at Netflix to
populate a structured log and database to track errors and error trends
across our world-wide population of drives.
Submitted by: imp, scottl
Approved by: kenm
MFC after: 3 days
Sponsored by: Netflix
Differential Revision: D5943
- Use pointer assignment rather than a combination of pointers and
flags to switch buffers between unmapped and mapped. This eliminates
multiple flags and generally simplifies the logic.
- Eliminate b_saveaddr since it is only used with pager bufs which have
their b_data re-initialized on each allocation.
- Gather up some convenience routines in the buffer cache for
manipulating buf space and buf malloc space.
- Add an inline, buf_mapped(), to standardize checks around unmapped
buffers.
In collaboration with: mlaier
Reviewed by: kib
Tested by: pho (many small revisions ago)
Sponsored by: EMC / Isilon Storage Division
tracking.
It is important to subtract the residual from the requested
transfer size to see how much data was actually transferred. With
tape drives in particular, it is common to request more data than is
returned.
Also, add I/O latency tracking for CAM requests issued by
cam_periph_runccb().
If the caller supplies a struct devstat, and the I/O is a SCSI or
ATA I/O, we will track the elapsed time to provide I/O latency
statistics for the request.
sys/cam/scsi/cam_periph.c:
In cam_periph_runccb(), subtract the residual when reporting I/O
totals to devstat(9) for SCSI and ATA passthrough requests.
In cam_periph_runccb(), grab the I/O start time and supply
the start time to devstat_end_transaction() so that it can
calculate the elapsed I/O time.
Sponsored by: Spectra Logic
MFC after: 1 week
VMware returns BUSY status when storage has transient connectivity issues.
It is often better to wait and let VM admin fix the problem then crash.
Discussed with: ken
MFC after: 1 week
we're now back to the pre-r228483 level of default verbosity. This in
turn again typically allows for reading information that userland might
have printed on the screen before initiating a halt, but still permits
to debug potential device shutdown problems on system shutdown via
CAM_DEBUG etc.
Reviewed by: mav
MFC after: 3 days
Sponsored by: Bally Wulff Games & Entertainment GmbH
reduce lock congestion and improve SMP scalability of the SCSI/ATA stack,
preparing the ground for the coming next GEOM direct dispatch support.
Replace big per-SIM locks with bunch of smaller ones:
- per-LUN locks to protect device and peripheral drivers state;
- per-target locks to protect list of LUNs on target;
- per-bus locks to protect reference counting;
- per-send queue locks to protect queue of CCBs to be sent;
- per-done queue locks to protect queue of completed CCBs;
- remaining per-SIM locks now protect only HBA driver internals.
While holding LUN lock it is allowed (while not recommended for performance
reasons) to take SIM lock. The opposite acquisition order is forbidden.
All the other locks are leaf locks, that can be taken anywhere, but should
not be cascaded. Many functions, such as: xpt_action(), xpt_done(),
xpt_async(), xpt_create_path(), etc. are no longer require (but allow) SIM
lock to be held.
To keep compatibility and solve cases where SIM lock can't be dropped, all
xpt_async() calls in addition to xpt_done() calls are queued to completion
threads for async processing in clean environment without SIM lock held.
Instead of single CAM SWI thread, used for commands completion processing
before, use multiple (depending on number of CPUs) threads. Load balanced
between them using "hash" of the device B:T:L address.
HBA drivers that can drop SIM lock during completion processing and have
sufficient number of completion threads to efficiently scale to multiple
CPUs can use new function xpt_done_direct() to avoid extra context switch.
Make ahci(4) driver to use this mechanism depending on hardware setup.
Sponsored by: iXsystems, Inc.
MFC after: 2 months
"Logical unit not supported" errors. First initiates specific target rescan,
second -- destroys specific LUN. That allows to automatically detect changes
in list of device LUNs. This mechanism doesn't work when target is completely
idle, but probably that is all what can be done without active polling.
Reviewed by: ken
Sponsored by: iXsystems, Inc.
Give periph validity flag own periph reference. That slightly simplifies
the release logic and covers hypothetical case if lock is dropped inside
the periph_oninval() method.
r248917, r248918, r248978, r249001, r249014, r249030:
Remove multilevel freezing mechanism, implemented to handle specifics of
the ATA/SATA error recovery, when post-reset recovery commands should be
allocated when queues are already full of payload requests. Instead of
removing frozen CCBs with specified range of priorities from the queue
to provide free openings, use simple hack, allowing explicit CCBs over-
allocation for requests with priority higher (numerically lower) then
CAM_PRIORITY_OOB threshold.
Simplify CCB allocation logic by removing SIM-level allocation queue.
After that SIM-level queue manages only CCBs execution, while allocation
logic is localized within each single device.
Suggested by: gibbs
r249017:
Some cosmetic things:
- Unify device to target insertion inside xpt_alloc_device() instead of
duplicating it three times.
- Remove extra checks for empty lists of devices and targets on release
since zero refcount check also implies it.
- Reformat code to reduce indentation.
r249103:
- Add lock assertions to every point where reference counters are modified.
- When reference counters are reaching zero, add assertions that there are
no children items left.
- Add a bit more locking to the xptpdperiphtraverse().
The problem was a race condition between the EDT traversal used by
things like 'camcontrol devlist', and CAM peripheral driver
removal.
The EDT traversal code holds the CAM topology lock, and wants
to show devices that have been invalidated. It acquires a
reference to the peripheral to make sure the peripheral it is
examining doesn't go away.
However, because the peripheral removal code in camperiphfree()
drops the CAM topology lock to call the peripheral's destructor
routine, we can run into a situation where the EDT traversal
increments the peripheral reference count after free process is
already in progress. At that point, the reference count is
ignored, because it was 0 when we started the process.
Fix this race by setting a flag, CAM_PERIPH_FREE, that I previously
added and checked in xptperiphtraverse() and xptpdperiphtravsere(),
but failed to use. If the EDT traversal code sees that flag,
it will know that the peripheral free process has already started,
and that it should not access that peripheral.
Also, fix an inconsistency in the locking between
xptpdperiphtraverse() and xptperiphtraverse(). They now both
hold the CAM topology lock while calling the peripheral traversal
function.
cam_xpt.c: Change xptperiphtraverse() to hold the CAM topology
lock across calls to the traversal function.
Take out the comment in xptpdperiphtraverse() that
referenced the locking inconsistency.
cam_periph.c: Set the CAM_PERIPH_FREE flag when we are in the
process of freeing a peripheral driver.
Sponsored by: Spectra Logic Corporation
MFC after: 1 week
System time is set later on boot process then initial bus scan by CAM.
Until that moment microtime() is equal to microuptime(), and if system
boots quickly, the value can be close to zero. That causes settle time
waiting even for buses that don't use reset during probe.
On my test system this reduces boot time by 1 second if USB enabled, or
by 4 seconds if USB disabled. CAM waited for ctl2cam0 bus "settle".
It includes three parts:
1) Modifications to CAM to detect media media changes and report them to
disk(9) layer. For modern SATA (and potentially UAS) devices it utilizes
Asynchronous Notification mechanism to receive events from hardware.
Active polling with TEST UNIT READY commands with 3 seconds period is used
for incapable hardware. After that both CD and DA drivers work the same way,
detecting two conditions: "NOT READY: Medium not present" after medium was
detected previously, and "UNIT ATTENTION: Not ready to ready change, medium
may have changed". First one reported to disk(9) as media removal, second
as media insert/change. To reliably receive second event new
AC_UNIT_ATTENTION async added to make UAs broadcasted to all periphs by
generic error handling code in cam_periph_error().
2) Modifications to GEOM core to handle media remove and change events.
Media removal handled by spoiling all consumers attached to the provider.
Media change event also schedules provider retaste after spoiling to probe
new media. New flag G_CF_ORPHAN was added to consumers to reflect that
consumer is in process of destruction. It allows retaste to create new
geom instance of the same class, while previous one is still dying.
3) Modifications to some GEOM classes: DEV -- to report media change
events to devd; VFS -- to handle spoiling same as orphan to prevent
accessing replaced media. PART class already handles spoiling alike to
orphan.
Reviewed by: silence on geom@ and scsi@
Tested by: avg
Sponsored by: iXsystems, Inc. / PC-BSD
MFC after: 2 months
