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>

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

Export req_lim via sysfs for debugging.
Signed-off-by: NBart Van Assche <bart.vanassche@gmail.com>
Acked-by: NDavid Dillow <dave@thedillows.org>
Signed-off-by: NRoland 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: NBart Van Assche <bart.vanassche@gmail.com>
Acked-by: NDavid Dillow <dave@thedillows.org>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Replace an open-coded dump of the receive buffer with a call to
print_hex_dump().
Signed-off-by: NBart Van Assche <bart.vanassche@gmail.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Instead of repeating the error unwinding steps in each place an error
can be detected, use the common idiom of gotos into an error flow.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

We can reduce the number of IB interrupts from two interrupts per
srp_queuecommand() call to one by using separate CQs for send and
receive completions and processing send completions by polling every
time a TX IU is allocated.

Receive completion events still trigger an interrupt.
Signed-off-by: NBart Van Assche <bart.vanassche@gmail.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Acked-by: NRoland Dreier <rolandd@cisco.com>
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is a much better version of a previous patch to make the parser
tables constant. Rather than changing the typedef, we put the "const" in
all the various places where its required, allowing the __initconst
exception for nfsroot which was the cause of the previous trouble.

This was posted for review some time ago and I believe its been in -mm
since then.
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>
Cc: Alexander Viro <aviro@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

They don't get updated by git and so they're worse than useless.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

The SRP initiator is currently using ib_find_cached_pkey() and
ib_get_cached_gid() in situations where the uncached ib_find_pkey()
and ib_query_gid() functions serve just as well: sleeping is allowed
and performance is not an issue.  Since we want to eliminate the
cached operations in the long term, convert SRP to use the uncached
variants.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

It's big, but there doesn't seem to be a way to split it up smaller...
Signed-off-by: NTony Jones <tonyj@suse.de>
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Cc: Roland Dreier <rolandd@cisco.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This sets us up to be able to convert the srp_host to use a struct
device instead of a class_device.

Based on a original patch from Tony Jones, but split up into this piece
by Greg.
Signed-off-by: NTony Jones <tonyj@suse.de>
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Reviewed-by: NRoland Dreier <rolandd@cisco.com>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The current SRP initiator will allow unlimited s/g entries in the
indirect descriptors lists, but the entry count field in the SRP_CMD
request is 8 bits, so setting srp_sg_tablesize too large will open the
possibility of wrapping the count and generating invalid requests.

Clamp srp_sg_tablesize to the protocol limits to prevent surprises.

Reported by Martin W. Schlining III <mschlining@datadirectnet.com>.
Signed-off-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

When a host just goes away (crash, power loss, etc.) without tearing
down its IB connections, it can get stale connection errors when it
tries to reconnect to targets upon rebooting.  Retrying the connection
a few times will prevent sysadmins from playing the "which disk(s)
went missing?" game.

This would have made things slightly quicker when tracking down some
of the recent bugs, but it also helps quite a bit when you've got a
large number of targets hanging off a wedged server.
Signed-off-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

With the sg table code, every SCSI driver is now either chain capable
or broken (or has sg_tablesize set so chaining is never activated), so
there's no need to have a check in the host template.

Also tidy up the code by moving the scatterlist size defines into the
SCSI includes and permit the last entry of the scatterlist pools not
to be a power of two.
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

When you have multiple targets, it gets really confusing when you try
to track down who did a reset when there is no identifying information
in the log message, especially when the same extension ID is mapped
through two different local IB ports.  So, add an identifier that can
be used to track back to which local IB port/remote target pair is the
one having problems.
Signed-off-by: NDavid Dillow <dillowda@ornl.gov>
Acked-by: NPete Wyckoff <pw@osc.edu>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

By default, the SCSI mid-layer seems to send down 512KB requests
(sg_tablesize = 256), with some requests occasionally combined. By
allowing the mid-layer to chain requests, we can easily grow to 1024KB
or larger -- I've tested 4096KB I/O requests with no problems.

I looked through the DMA paths on the hardware drivers to ensure they
could take advantage of the SG chaining, and it seems that every one
except ipath uses the system's DMA routines, which have been converted
to handle chaining.  ipath looks like it should be OK, but I have no
way to test it.
Signed-off-by: NDavid Dillow <dillowda@ornl.gov>

[ Tested on ipath.  - Roland ]
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

The current SRP initiator will send requests even if it has no credits
available.  The results of sending extra requests are vendor specific,
but on some devices, overrunning credits will cost 85% of peak
performance -- e.g. 100 MB/s vs 720 MB/s.  Other devices may just drop
the requests.

This patch will tell the SCSI midlayer to queue requests if there are
fewer than two credits remaining, and will not issue a task management
request if there are no credits remaining.  The mid-layer will retry
the queued command once an outstanding command completes.

The patch also removes the unlikely() in __srp_get_tx_iu(), as it is
not at all unlikely to hit this limit under heavy load.
Signed-off-by: NDavid Dillow <dillowda@ornl.gov>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

The documented call sequence for removing a host is to call the
transport xxx_remove_host() prior to scsi_remove_host(). The SRP
transport used to crash when that order was followed, but as it is now
fixed, use the documented order.
Signed-off-by: NDavid Dillow <dillowda@ornl.gov>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add a missing call to srp_remove_host() in srp_remove_one() so that we 
don't leak SRP transport class list entries.
Tested-by: NDavid Dillow <dillowda@ornl.gov>
Acked-by: NFUJITA Tomonori <tomof@acm.org>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

This adds a 'roles' attribute to rport like transport_fc. The role can
be initiator or target. That is, the initiator driver creates target
remote ports and the target driver creates initiator remote ports.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

This converts ib_srp to use the srp transport class.

I don't have ib hardware so I've not tested this patch.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Provide the target service ID when performing a path record query to
support optional QoS capability.  QoS requires support from the SA.
Signed-off-by: NSean Hefty <sean.hefty@intel.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

New Cisco IB SRP targets use the Cisco OUI 00-1b-0d but still need the
Topspin workarounds.  Add this OUI to srp_target_is_topspin().
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Wrap the checking for Mellanox and Topspin OUIs to decide whether to
use a workaround into helper functions.  This will make it cleaner to
add a new OUI to check (as we need to do now that some targets with a
Cisco OUI still need the Topspin workarounds).
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

- remove the unnecessary map_single path.

- convert to use the new accessors for the sg lists and the
parameters.

Jens Axboe <jens.axboe@oracle.com> did the for_each_sg cleanup.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: NRoland Dreier <rdreier@cisco.com>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Add a num_comp_vectors member to struct ib_device and extend
ib_create_cq() to pass in a comp_vector parameter -- this parallels
the userspace libibverbs API.  Update all hardware drivers to set
num_comp_vectors to 1 and have all ULPs pass 0 for the comp_vector
value.  Pass the value of num_comp_vectors to userspace rather than
hard-coding a value of 1.

We want multiple CQ event vector support (via MSI-X or similar for
adapters that can generate multiple interrupts), but it's not clear
how many vectors we want, or how we want to deal with policy issues
such as how to decide which vector to use or how to set up interrupt
affinity.  This patch is useful for experimenting, since no core
changes will be necessary when updating a driver to support multiple
vectors, and we know that we want to make at least these changes
anyway.
Signed-off-by: NMichael S. Tsirkin <mst@dev.mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add an orig_dgid attribute in sysfs for SRP scsi_hosts, so that
userspace can tell what the original dgid value written to the
add_target file was, even if the connection is redirected to a
different port while connecting.
Signed-off-by: NIshai Rabinovitz <ishai@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

When there is a call to send_tsk_mgmt SRP posts a send and waits for 5
seconds to get a response.

When the QP is in the error state it is obvious that there will be no
response so it is quite useless to wait.  In fact, the timeout causes
SRP to wait a long time to reconnect when a QP error occurs. (Each
abort and each reset_device calls send_tsk_mgmt, which waits for the
timeout).  The following patch solves this problem by identifying the
failure and returning an immediate error code.
Signed-off-by: NIshai Rabinovitz <ishai@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Checks if the kmalloc in match_strdup() was successful, and bail out
on looking at the token if it failed.
Signed-off-by: NIshai Rabinovitz <ishai@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>