RFC3270 mandates that iSCSI PDUs are padded to the closest integer
number of four byte words.  Fix the iser code to support that on both
the TX/RX flows.
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.co.il>
Signed-off-by: NRoland Dreier <roland@purestorage.com>

This pactch has iser export the address and port
of the endpoint.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

The iser connection teardown flow isn't over until the underlying
Connection Manager (e.g the IB CM) delivers a disconnected or timeout
event through the RDMA-CM.  When the remote (target) side isn't
reachable, e.g when some HW e.g port/hca/switch isn't functioning or
taken down administratively, the CM timeout flow is used and the event
may be generated only after relatively long time -- on the order of
tens of seconds.

The current iser code exposes this possibly long delay to higher
layers, specifically to the iscsid daemon and iscsi kernel stack. As a
result, the iscsi stack doesn't respond well: this low-level CM delay
is added to the fail-over time under HA schemes such as the one
provided by DM multipath through the multipathd(8) service.

This patch enhances the reference counting scheme on iser's IB
connections so that the disconnect flow initiated by iscsid from user
space (ep_disconnect) doesn't wait for the CM to deliver the
disconnect/timeout event.  (The connection teardown isn't done from
iser's view point until the event is delivered)

The iser ib (rdma) connection object is destroyed when its reference
count reaches zero.  When this happens on the RDMA-CM callback
context, extra care is taken so that the RDMA-CM does the actual
destroying of the associated ID, since doing it in the callback is
prohibited.

The reference count of iser ib connection normally reaches three,
where the <ref, deref> relations are

 1. conn <init, terminate>
 2. conn <bind, stop/destroy>
 3. cma id <create, disconnect/error/timeout callbacks>

With this patch, multipath fail-over time is about 30 seconds, while
without this patch, multipath fail-over time is about 130 seconds.
Signed-off-by: NOr Gerlitz <ogerlitz@voltaire.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

The iscsi_eh_target_reset has been modified to attempt
target reset only. If it fails, then iscsi_eh_session_reset
will be called.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJayamohan Kallickal <jayamohank@serverengines.com>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

libiscsi passthrough mode invokes the transport xmit calls directly
without first going through an internal queue, unlike the other mode,
which uses a queue and a xmitworker thread.  Now that the "cant_sleep"
prerequisite of iscsi_host_alloc is met, move to use it.  Handling
xmit errors is now done by the passthrough flow of libiscsi.  Since
the queue/worker aren't used in this mode, the code that schedules the
xmitworker is removed.
Signed-off-by: NOr Gerlitz <ogerlitz@voltaire.com>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Simplify and shrink the logic/code used for the send descriptors.
Changes include removing struct iser_dto (an unnecessary abstraction),
using struct iser_regd_buf only for handling SCSI commands, using
dma_sync instead of dma_map/unmap, etc.
Signed-off-by: NOr Gerlitz <ogerlitz@voltaire.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Currently, the recv buffer posting logic is based on the transactional
nature of iSER which allows for posting a buffer before sending a PDU.
Change this to post only when the number of outstanding recv buffers
is below a water mark and in a batched manner, thus simplifying and
optimizing the data path.  Use a pre-allocated ring of recv buffers
instead of allocating from kmem cache.  A special treatment is given
to the login response buffer whose size must be 8K unlike the size of
buffers used for any other purpose which is 128 bytes.
Signed-off-by: NOr Gerlitz <ogerlitz@voltaire.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

When iser enabled lu reset support it did not set the
bit to allow userspace to get/set the timeout. This
sets the tgt and lu reset timeout bits.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

This patch contains changes that allow iscsi_session_setup
to allocate private space for LLD's
Signed-off-by: NJayamohan Kallickal <jayamohank@serverengines.com>
Acked-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

If a task did not complete normally due to a TMF, libiscsi will
now complete the task with the state ISCSI_TASK_ABRT_TMF. Drivers
like bnx2i that need to free resources if a command did not complete normally
can then check the task state. If a driver does not need to send
a special command if we have dropped the session then they can check
for ISCSI_TASK_ABRT_SESS_RECOV.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

When we create the tcp/ip connection by calling ep_connect, we currently
just go by the routing table info.

I think there are two problems with this.

1. Some drivers do not have access to a routing table. Some drivers like
qla4xxx do not even know about other ports.

2. If you have two initiator ports on the same subnet, the user may have
set things up so that session1 was supposed to be run through port1. and
session2 was supposed to be run through port2. It looks like we could
end with both sessions going through one of the ports.

Fixes for cxgb3i from Karen Xie.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Set target can queue limit to the number of preallocated
session tasks we have.

This along with the cxgb3i can_queue patch will fix a throughput
problem where it could only queue one LU worth of data at a time.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

We do not need to have llds set the host no for the session's
parent, because we know the session's parent is going to be
the host. This removes it from the session creation callback
and converts the drivers.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

The qdepth setting was useful when we needed libiscsi to verify
the setting. Now we just need to make sure if older tools
passed in zero then we need to set some default.

So this patch just has us use the sht->cmd_per_lun or if
for LLD does a host per session then we can set it on per
host basis.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

We were using the shost work queue which ended up being
a little akward since all iscsi hosts need a thread for
scanning, but only drivers hooked into libiscsi need
a workqueue for transmitting. So this patch moves the
xmit workqueue to the lib.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

There is no need to cap the queue depth in the modules. We set
this in userspace and can do that there. For performance testing
with ram based targets, this is helpful since we can have very
high queue depths.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

iser has its own logging inrfastrucutre. Convert it to use
it instead of libiscsi.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

We do not need to allocate a itt for data_out, so this
passes the opcode to the alloc_pdu callout.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This just converts iser to new alloc_pdu api. It still
preallocates the pdu, so there is no difference.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

I had this in my patchset to add target reset support, but
it got dropped due to patching conflicts. This initial patch
just renames the function and users. We are actually just
dropping the session, and so this does not have anything to do
with the host exactly. It does for software iscsi because
we allocate a host per session, but for cxgb3i this makes no
sense.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

If the driver knows when hardware is removed like with cxgb3i,
bnx2i, qla4xxx and iser then we will want to remove the sessions/devices
that are bound to that device before removing the host.

cxgb3i and in the future bnx2i will remove the host and that will
remove all the sessions on the hba. iser can call iscsi_kill_session
when it gets an event that indicates that a hca is removed.
And when qla4xxx is hooked in to the lib (it is only hooked into
the class right now) it can call iscsi remove host like the
partial offload card drivers.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

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

This patch fixes two bugs that are related.

1. Old tools did not set can_queue/cmds_max. This patch modifies
libiscsi so that when we add the host we catch this and set it
to the default.

2. iscsi_tcp thought that the scsi command that was passed to
the eh functions needed a iscsi_cmd_task allocated for it. It
only needed a mgmt task, and now it does not matter since it
all comes from the same pool and libiscsi handles this for the
drivers. ib_iser had copied iscsi_tcp's code and set can_queue
to its max - 1 to handle this. So this patch removes the max -1,
and just sets it to the max.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

The recv lock was defined so the iscsi layer could block
the recv path from processing IO during recovery. It
turns out iser just set a lock to that pointer which was pointless.

We now disconnect the transport connection before doing recovery
so we do not need the recv lock. For iscsi_tcp we still stop
the recv path incase older tools are being used.

This patch also has iscsi_itt_to_ctask user grab the session lock
and has the caller access the task with the lock or get a ref
to it in case the target is broken and sends a tmf success response
then sends data or a response for the command that was supposed to
be affected bty the tmf.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This adds two new attrs used for creating initiator ports and
binding sessions to hardware.

The session level initiatorname:

Since bnx2i does a scsi_host per host device, we need to add the
iface initiator port settings on the session, so we can create
multiple initiator ports (each with different inames) per device/scsi_host.

The current iname reflects that qla4xxx can have one iname per hba, and we are
allocating a host per session for software. The iname on the host will
remain so we can export and set the hba level qla4xxx setting.

The ifacename attr:

To bind a session to a some peice of hardware in userspace we maintain
some mappings, but during boot or iscsid restart (iscsid contains the user
space part of the driver) we need to be able to figure out which of those
host mappings abstractions maps to certain sessions. This patch adds
a ifacename attr, which userspace can set to id the host side of the
endpoint across pivot_roots and iscsid restarts.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This hooks iser into the iscsi endpoint code. Previously it handled the
lookup and allocation. This has been made generic so bnx2i and iser can
share it. It also allows us to pass iser the leading conn's ep, so we
know the ib_deivce being used and can set it as the scsi_host's parent.
And that allows scsi-ml to set the dma_mask based on those values.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Currently we duplicate the list of sessions, because we were using the
test for if a session was on the host list to indicate if the session
was bound or unbound. We can instead use the target_id and fix up
the class so that drivers like bnx2i do not have to manage the target id
space.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This handles the iscsi_cmd_task rename and renames
the iser cmd task to iser task.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Convert ib_iser to support merged tasks.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Currently to get a ctask from the session cmd array, you have to
know to use the itt modifier. To make this easier on LLDs and
so in the future we can easilly kill the session array and use
the host shared map instead, this patch adds a nice wrapper
to strip the itt into a session->cmds index and return a ctask.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

After the stop_conn callback has returned the LLD should not
touch the scsi cmds. iscsi_tcp and libiscsi use the
conn->recv_lock and suspend_rx field to halt recv path
processing, but iser does not have any protection.

This patch modifies iser so that userspace can just
call the ep_disconnect callback, which will halt
all recv IO, before calling the stop_conn callback so
we do not have to worry about the conn->recv_lock and
suspend rx field. iser just needs to stop the send side
from accessing the ib conn.

Fixup to handle when the ep poll fails and ep disconnect
is called from Erez.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This removes the session and conn data_size fields from the iscsi_transport.
Just pass in the value like with host allocation. This patch also makes
it so the LLD iscsi_conn data is allocated with the iscsi_cls_conn.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This finishes the host/session unbinding, by adding some helpers
to add and remove hosts and the session they manage.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

bnx2i allocates a host per netdevice but will use libiscsi,
so this unbinds the session from the host in that code.

This will also be useful for the iser parent device dma settings
fixes.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

max_cmd_len and max_conn are not really used. max_cmd_len is
always 16 and can be set by the LLD. max_conn is always one
since we do not support MCS.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

iscsi offload (bnx2i and qla4xx) allocate a scsi host per hba,
so the session creation path needs a shost/host_no argument.
Software iscsi/iser will follow the same behabior as before
where it allcoates a host per session, but in the future iser
will probably look more like bnx2i where the host's parent is
the hardware (rnic for iser and for bnx2i it is the nic), because
it does not use a socket layer like how iscsi_tcp does.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Count FMR alignment violations per session as part of the iscsi
statistics.
Signed-off-by: NEli Dorfman <elid@voltaire.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

Add a .change_queue_depth handler to the scsi_host_template in the
iSER driver.  iscsi_change_queue_depth was added to iscsi_tcp in order
to solve the problem of queue depth which was too high for some
targets.  It is also applicable for iSER.
Signed-off-by: NErez Zilber <erezz@voltaire.com>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>

eh_device_reset_handler was already added to scsi_host_template
in iscsi_tcp, and is now added also for iscsi_iser.
Signed-off-by: NErez Zilber <erezz@voltaire.com>
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>