If an SRP target is no longer reachable and srp_reset_host() fails to
reconnect then ib_srp will invoke scsi_remove_host(). That function
will invoke __scsi_remove_device() for each LUN. And that last
function will change the device state from SDEV_TRANSPORT_OFFLINE into
SDEV_CANCEL. Certain user space software, e.g. older versions of
multipathd, continue queueing I/O to SCSI devices that are in the
SDEV_CANCEL state.
If these I/O requests are submitted as SG_IO that means that the
REQ_PREEMPT flag will be set and hence that these requests will be
passed to srp_queuecommand(). These requests will time out. If new
requests are queued fast enough from user space these active requests
will prevent __scsi_remove_device() to finish.
Avoid this by failing I/O requests in the SDEV_CANCEL state if the
transport is offline. Introduce a new variable to keep track of the
transport state instead of failing requests if (!target->connected ||
target->qp_in_error), so that the SCSI error handler has a chance to
retry commands after a transport layer failure occurred.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: <stable@vger.kernel.org> # 3.8
Signed-off-by: Roland Dreier <roland@purestorage.com>
If a SCSI command times out it is passed to the SCSI error
handler. The SCSI error handler will try to abort the commands that
timed out. If aborting fails, a device reset will be attempted. If
the device reset also fails a host reset will be attempted. If the
host reset also fails the whole procedure will be repeated.
srp_abort() and srp_reset_device() fail for a QP in the error state.
srp_reset_host() fails after host removal has started. Hence if the
SCSI error handler gets invoked after host removal has started and
with the QP in the error state an endless loop will be triggered.
Modify the SCSI error handling functions in ib_srp as follows:
- Abort SCSI commands properly even if the QP is in the error state.
- Make srp_reset_host() reset SCSI requests even after host removal
has already started or if reconnecting fails.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dave@thedillows.org>
Cc: <stable@vger.kernel.org> # 3.8
Signed-off-by: Roland Dreier <roland@purestorage.com>
Do not send a task management function if sending will fail anyway
because either there is no RDMA/RC connection or the QP is in the
error state.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dave@thedillows.org>
Cc: <stable@vger.kernel.org> # 3.8
Signed-off-by: Roland Dreier <roland@purestorage.com>
Remove an assignment that incorrectly overwrites the connection state
update by srp_connect_target().
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dave@thedillows.org>
Cc: <stable@vger.kernel.org> # 3.8
Signed-off-by: Roland Dreier <roland@purestorage.com>
Make it possible to disconnect the IB RC connection used by the SRP
protocol to communicate with a target.
Have the SRP transport layer create a sysfs "delete" attribute for
initiator drivers that support this functionality.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Now that SRP recreates the CM ID, QP, and CQ for each connection,
there is no need to wait for the timewait state to complete.
Signed-off-by: Vu Pham <vu@mellanox.com>
Signed-off-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>
HW QP FATAL errors persist over a reset operation, but we can recover
from that by recreating the QP and associated CQs for each connection.
Creating a new QP/CQ also completely forecloses any possibility of
getting stale completions or packets on the new connection.
Signed-off-by: Ishai Rabinovitz <ishai@mellanox.co.il>
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
[ updated to current code from OFED, cleaned up commit message ]
Signed-off-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Only queue removal work after having changed the target state
into SRP_TARGET_REMOVED and not if that state was already equal
to SRP_TARGET_REMOVED. That allows us to remove the state
SRP_TARGET_DEAD. Add a call to srp_disconnect_target() in
srp_remove_target() -- due to previous changes it is now safe to
invoke that function even if the IB connection has already
been disconnected. This change allows us to replace the target
removal code in srp_remove_one() by an (indirect) call to
srp_remove_target(). Rename srp_target_port.work into
srp_target_port.remove_work to reflect its usage.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Keep track of the connection state. Only report QP errors while
connected. Only invoke ib_send_cm_dreq() when connected so that
invoking srp_disconnect_target() after having received a DREQ does not
cause an error message to be printed.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
If the RDMA RC connection is closed, tell the SCSI mid-layer to
terminate all pending commands instead of only the first.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Introduce the function srp_handle_qp_err(), change the type of
qp_in_error from int into bool and move the initialization of that
variable from srp_reconnect_target() to srp_connect_target().
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Since scsi_remove_host() has been modified so that SCSI error handling
functions will no longer be invoked after scsi_remove_host() returns,
the test at the start of srp_send_tsk_mgmt() is now superfluous.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Some SCSI upper layer drivers, e.g. sd, issue SCSI commands from
inside scsi_remove_host() (see the sd_shutdown() call in sd_remove()).
Make sure that these commands have a chance to reach the SCSI device.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Block the SCSI host while reconnecting instead of representing the
reconnection activity as a distinct SRP target state. This allows us
to eliminate the target state SRP_TARGET_CONNECTING.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Increase the block layer timeout for disks so that it is above the
InfiniBand transport layer timeout.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
We need to call scsi_done() for commands after we abort them.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Cc: <stable@vger.kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>
srp_free_req() uses the scsi_cmnd structure contents to unmap
buffers, so we must invoke srp_free_req() before we release
ownership of that structure.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Cc: <stable@vger.kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Avoid a crash caused by the scmnd->scsi_done(scmnd) call in
srp_process_rsp() being invoked with scsi_done == NULL. This can
happen if a reply is received during or after a command abort.
Reported-by: Joseph Glanville <joseph.glanville@orionvm.com.au>
Reference: http://marc.info/?l=linux-rdma&m=134314367801595
Cc: <stable@vger.kernel.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Remove sysfs attributes before removing a target instead of testing
the target state in every sysfs attribute callback method. Note: it is
safe to invoke a sysfs attribute removal method like
device_remove_file() twice on the same attribute.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Use pr_fmt() and pr_xxx() instead of more verbose printk() equivalents.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>
Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SCSI scanning of a channel🆔lun triplet in Linux works as follows
(function scsi_scan_target() in drivers/scsi/scsi_scan.c):
- If lun == SCAN_WILD_CARD, send a REPORT LUNS command to the target
and process the result.
- If lun != SCAN_WILD_CARD, send an INQUIRY command to the LUN
corresponding to the specified channel🆔lun triplet to verify
whether the LUN exists.
So a SCSI driver must either take the channel and target id values in
account in its quecommand() function or it should declare that it only
supports one channel and one target id.
Currently the ib_srp driver does neither. As a result scanning the
SCSI bus via e.g. rescan-scsi-bus.sh causes many duplicate SCSI
devices to be created. For each 0:0:L device, several duplicates are
created with the same LUN number and with (C:I) != (0:0). Fix this by
declaring that the ib_srp driver only supports one channel and one
target id.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: <stable@kernel.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Fix
drivers/infiniband/ulp/srp/ib_srp.c: In function 'srp_handle_recv':
drivers/infiniband/ulp/srp/ib_srp.c:1150: warning: cast to pointer from integer of different size
drivers/infiniband/ulp/srp/ib_srp.c: In function 'srp_send_completion':
drivers/infiniband/ulp/srp/ib_srp.c🔢 warning: cast to pointer from integer of different size
by adding an intermediate cast to uintptr_t.
Signed-off-by: Roland Dreier <roland@purestorage.com>
Acked-by: David Dillow <dillowda@ornl.gov>
Now that we can get larger SG lists, we can take advantage of HCAs that
allow us to use larger FMR sizes. In many cases, we can use up to 512
entries, so start there and work our way down.
Signed-off-by: David Dillow <dillowda@ornl.gov>
This allows us to guarantee the ability to submit up to 8 MB requests
based on the current value of SCSI_MAX_SG_CHAIN_SEGMENTS. While FMR will
usually condense the requests into 8 SG entries, it is imperative that
the target support external tables in case the FMR mapping fails or is
not supported.
We add a safety valve to allow targets without the needed support to
reap the benefits of the large tables, but fail in a manner that lets
the user know that the data didn't make it to the device. The user must
add "allow_ext_sg=1" to the target parameters to indicate that the
target has the needed support.
If indirect_sg_entries is not specified in the modules options, then
the sg_tablesize for the target will default to cmd_sg_entries unless
overridden by the target options.
Signed-off-by: David Dillow <dillowda@ornl.gov>
Instead of forcing all of the S/G entries to fit in one FMR, and falling
back to indirect descriptors if that fails, allow the use of as many
FMRs as needed to map the request. This lays the groundwork for allowing
indirect descriptor tables that are larger than can fit in the command
IU, but should marginally improve performance now by reducing the number
of indirect descriptors needed.
We increase the minimum page size for the FMR pool to 4K, as larger
pages help increase the coverage of each FMR, and it is rare that the
kernel would send down a request with scattered 512 byte fragments.
This patch also move some of the target initialization code afte the
parsing of options, to keep it together with the new code that needs to
allocate memory based on the options given.
Signed-off-by: David Dillow <dillowda@ornl.gov>
Different configurations of target software allow differing max sizes of
the command IU. Allowing this to be changed per-target allows all
targets on an initiator to get an optimal setting.
We deprecate srp_sg_tablesize and replace it with cmd_sg_entries in
preparation for allowing more indirect descriptors than can fit in the
IU.
Signed-off-by: David Dillow <dillowda@ornl.gov>
It is unclear exactly how this code works around Mellanox SRP targets,
or if the problem is on the target side or in the HCA itself. In an
abundance of caution, we should always enable the workaround.
Signed-off-by: David Dillow <dillowda@ornl.gov>
* ib_wq is added, which is used as the common workqueue for infiniband
instead of the system workqueue. All system workqueue usages
including flush_scheduled_work() callers are converted to use and
flush ib_wq.
* cancel_delayed_work() + flush_scheduled_work() converted to
cancel_delayed_work_sync().
* qib_wq is removed and ib_wq is used instead.
This is to prepare for deprecation of flush_scheduled_work().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Merge the two tests in srp_queuecommand() of whether information unit
allocation succeeded into one. An intended side effect of this change
is that we fix the warning:
drivers/infiniband/ulp/srp/ib_srp.c: In function 'srp_queuecommand':
drivers/infiniband/ulp/srp/ib_srp.c:1116: warning: 'req' may be used uninitialized in this function
(seen with CONFIG_CC_OPTIMIZE_FOR_SIZE=y at least with gcc 4.4.4)
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Put the variables accessed together in the hot-path into common
cachelines, and separate them by RW vs RO to avoid false dirtying.
We keep a local copy of the lkey and rkey in the target to avoid
traversing pointers (and associated cache lines) to find them.
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: David Dillow <dillowda@ornl.gov>
We don't need protection against the SCSI stack, so use our own lock to
allow parallel progress on separate CPUs.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
[ broken out and small cleanups by David Dillow ]
Signed-off-by: David Dillow <dillowda@ornl.gov>
We only need the lock to cover list and credit manipulations, so push
those into srp_remove_req() and update the call chains.
We reorder the request removal and command completion in
srp_process_rsp() to avoid the SCSI mid-layer sending another command
before we've released our request and added any credits returned by the
target. This prevents us from returning HOST_BUSY unneccesarily.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
[ broken out, small cleanups, and modified to avoid potential extraneous
HOST_BUSY returns by David Dillow ]
Signed-off-by: David Dillow <dillowda@ornl.gov>
We only need locks to protect our lists and number of credits available.
By pre-consuming the credit for the request, we can reduce our lock
coverage to just those areas. If we don't actually send the request,
we'll need to put the credit back into the pool.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
[ broken out and small cleanups by David Dillow ]
Signed-off-by: David Dillow <dillowda@ornl.gov>
We use req->scmnd != NULL to indicate an active request, so there's no
need to keep a separate list for them. We can afford the array iteration
during error handling, and dropping it gives us one less item that needs
lock protection.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
[ broken out and small cleanups by David Dillow ]
Signed-off-by: David Dillow <dillowda@ornl.gov>
Only one CPU at a time will own an RX IU, so using the address of the IU
as the work request cookie allows us to avoid taking a lock. We can
similarly prepare the TX path for lockless posting by moving the free TX
IUs to a list. This also removes the requirement that the queue sizes be
a power of 2.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
[ broken out, small cleanups, and modified to avoid needing an extra field
in the IU by David Dillow]
Signed-off-by: David Dillow <dillowda@ornl.gov>
We can only have one task management comment outstanding, so move the
completion and status to the target port. This allows us to handle
resets of a LUN without a corresponding request having been sent.
Meanwhile, we don't need to play games with host_scribble, just use it
as the pointer it is.
This fixes a crash when we issue a bus reset using sg_reset.
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=13893
Reported-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: David Dillow <dillowda@ornl.gov>
Move the mid-layer's ->queuecommand() invocation from being locked
with the host lock to being unlocked to facilitate speeding up the
critical path for drivers who don't need this lock taken anyway.
The patch below presents a simple SCSI host lock push-down as an
equivalent transformation. No locking or other behavior should change
with this patch. All existing bugs and locking orders are preserved.
Additionally, add one parameter to queuecommand,
struct Scsi_Host *
and remove one parameter from queuecommand,
void (*done)(struct scsi_cmnd *)
Scsi_Host* is a convenient pointer that most host drivers need anyway,
and 'done' is redundant to struct scsi_cmnd->scsi_done.
Minimal code disturbance was attempted with this change. Most drivers
needed only two one-line modifications for their host lock push-down.
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Acked-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
srp_send_tsk_mgmt() was missing the proper DMA sync calls before posting
the buffer to the device.
Signed-off-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Use the list_first_entry() macro in ib_srp instead of open-coding the equivalent,
which makes the source code slightly more descriptive. The list_first_entry()
macro itself was introduced in kernel 2.6.22.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
As proposed by the SRP (draft) standard, ib_srp reserves one ring
element for SRP_TSK_MGMT requests. This patch makes sure that the SCSI
mid-layer never tries to queue more than (SRP request limit) - 1 SCSI
commands to ib_srp. This improves performance for targets whose request
limit is less than or equal to SRP_NORMAL_REQ_SQ_SIZE by reducing the
number of BUSY responses reported by ib_srp to the SCSI mid-layer.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This patch adds support for SRP_CRED_REQ to avoid a lockup by targets
that use that mechanism to return credits to the initiator. This
prevents a lockup observed in the field where we would never add the
credits from the SRP_CRED_REQ to our current count, and would therefore
never send another command to the target.
Minimal support for SRP_AER_REQ is also added, as these messages can
also be used to convey additional credits to the initiator.
Based upon extensive debugging and code by Bart Van Assche and a bug
report by Chris Worley.
Signed-off-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
The transmit ring in ib_srp (srp_target.tx_ring) is currently only used
for allocating requests sent by the initiator to the target. This patch
prepares using that ring for allocation of both requests and responses.
Also, this patch differentiates the uses of SRP_SQ_SIZE, increases the
size of the IB send completion queue by one element and reserves one
transmit ring slot for SRP_TSK_MGMT requests.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Export req_lim via sysfs for debugging.
Signed-off-by: Bart Van Assche <bart.vanassche@gmail.com>
Acked-by: David Dillow <dave@thedillows.org>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
The current strategy in ib_srp for posting receive buffers is:
* Post one buffer after channel establishment.
* Post one buffer before sending an SRP_CMD or SRP_TSK_MGMT to the target.
As a result, only the first non-SRP_RSP information unit from the
target will be processed. If that first information unit is an
SRP_T_LOGOUT, it will be processed. On the other hand, if the
initiator receives an SRP_CRED_REQ or SRP_AER_REQ before it receives a
SRP_T_LOGOUT, the SRP_T_LOGOUT won't be processed.
We can fix this inconsistency by changing the strategy for posting
receive buffers to:
* Post all receive buffers after channel establishment.
* After a receive buffer has been consumed and processed, post it again.
A side effect is that the ib_post_recv() call is moved out of the SCSI
command processing path. Since __srp_post_recv() is not called
directly any more, get rid of it and move the code directly into
srp_post_recv(). Also, move srp_post_recv() up in the file to avoid a
forward declaration.
Signed-off-by: Bart Van Assche <bart.vanassche@gmail.com>
Acked-by: David Dillow <dave@thedillows.org>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
