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: NVu Pham <vu@mellanox.com>
Signed-off-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NRoland 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: NIshai Rabinovitz <ishai@mellanox.co.il>
Signed-off-by: NMichael S. Tsirkin <mst@mellanox.co.il>

[ updated to current code from OFED, cleaned up commit message ]
Signed-off-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Increase the block layer timeout for disks so that it is above the
InfiniBand transport layer timeout.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

We need to call scsi_done() for commands after we abort them.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Cc: <stable@vger.kernel.org>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Cc: <stable@vger.kernel.org>
Signed-off-by: NRoland 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: NJoseph Glanville <joseph.glanville@orionvm.com.au>
Reference: http://marc.info/?l=linux-rdma&m=134314367801595
Cc: <stable@vger.kernel.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

Use pr_fmt() and pr_xxx() instead of more verbose printk() equivalents.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland 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: NArun Sharma <asharma@fb.com>
Reviewed-by: NEric 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: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

SCSI scanning of a channel:id: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:id: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: NBart Van Assche <bvanassche@acm.org>
Cc: <stable@kernel.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland 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:1234: warning: cast to pointer from integer of different size

by adding an intermediate cast to uintptr_t.
Signed-off-by: NRoland Dreier <roland@purestorage.com>
Acked-by: NDavid 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: NDavid 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: NDavid 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: NDavid 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: NDavid Dillow <dillowda@ornl.gov>

This is to clean up prior to further changes.
Signed-off-by: NDavid 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: NDavid 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: NTejun Heo <tj@kernel.org>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Acked-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NDavid 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: NBart Van Assche <bvanassche@acm.org>
[ broken out and small cleanups by David Dillow ]
Signed-off-by: NDavid 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: NBart Van Assche <bvanassche@acm.org>
[ broken out, small cleanups, and modified to avoid potential extraneous
  HOST_BUSY returns by David Dillow ]
Signed-off-by: NDavid 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: NBart Van Assche <bvanassche@acm.org>
[ broken out and small cleanups by David Dillow ]
Signed-off-by: NDavid 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: NBart Van Assche <bvanassche@acm.org>
[ broken out and small cleanups by David Dillow ]
Signed-off-by: NDavid 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: NBart 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: NDavid Dillow <dillowda@ornl.gov>

Signed-off-by: NBart Van Assche <bvanassche@acm.org>
[ broken out and small cleanups by David Dillow ]
Signed-off-by: NDavid 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=13893Reported-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NDavid 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: NJeff Garzik <jgarzik@redhat.com>
Acked-by: NJames Bottomley <James.Bottomley@suse.de>
Signed-off-by: NLinus 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: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland 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: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Signed-off-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>