Commit Graph

494135 Commits

Author SHA1 Message Date
Roland Dreier
a7cfef21e3 Merge branches 'core', 'cxgb4', 'ipoib', 'iser', 'mlx4', 'ocrdma', 'odp' and 'srp' into for-next 2014-12-15 18:19:20 -08:00
Haggai Eran
b4cfe447d4 IB/mlx5: Implement on demand paging by adding support for MMU notifiers
* Implement the relevant invalidation functions (zap MTTs as needed)
* Implement interlocking (and rollback in the page fault handlers) for
  cases of a racing notifier and fault.
* With this patch we can now enable the capability bits for supporting RC
  send/receive/RDMA read/RDMA write, and UD send.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:19:04 -08:00
Haggai Eran
eab668a6d0 IB/mlx5: Add support for RDMA read/write responder page faults
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:19:03 -08:00
Haggai Eran
7bdf65d411 IB/mlx5: Handle page faults
This patch implement a page fault handler (leaving the pages pinned as
of time being).  The page fault handler handles initiator and responder
page faults for UD/RC transports, for send/receive operations, as well
as RDMA read/write initiator support.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:19:03 -08:00
Haggai Eran
6aec21f6a8 IB/mlx5: Page faults handling infrastructure
* Refactor MR registration and cleanup, and fix reg_pages accounting.
* Create a work queue to handle page fault events in a kthread context.
* Register a fault handler to get events from the core for each QP.

The registered fault handler is empty in this patch, and only a later
patch implements it.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:19:03 -08:00
Haggai Eran
832a6b06ab IB/mlx5: Add mlx5_ib_update_mtt to update page tables after creation
The new function allows updating the page tables of a memory region
after it was created. This can be used to handle page faults and page
invalidations.

Since mlx5_ib_update_mtt will need to work from within page invalidation,
so it must not block on memory allocation. It employs an atomic memory
allocation mechanism that is used as a fallback when kmalloc(GFP_ATOMIC) fails.

In order to reuse code from mlx5_ib_populate_pas, the patch splits
this function and add the needed parameters.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:19:02 -08:00
Haggai Eran
cc149f751b IB/mlx5: Changes in memory region creation to support on-demand paging
This patch wraps together several changes needed for on-demand paging support
in the mlx5_ib_populate_pas function, and when registering memory regions.

* Instead of accepting a UMR bit telling the function to enable all
  access flags, the function now accepts the access flags themselves.
* For on-demand paging memory regions, fill the memory tables from the
  correct list, and enable/disable the access flags per-page according
  to whether the page is present.
* A new bit is set to enable writing of access flags when using the
  firmware create_mkey command.
* Disable contig pages when on-demand paging is enabled.

In addition the patch changes the UMR code to use PTR_ALIGN instead of
our own macro.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:19:02 -08:00
Haggai Eran
8cdd312cfe IB/mlx5: Implement the ODP capability query verb
The patch adds infrastructure to query ODP capabilities in the mlx5
driver. The code will read the capabilities from the device, and
enable only those capabilities that both the driver and the device
supports.  At this point ODP is not supported, so no capability is
copied from the device, but the patch exposes the global ODP device
capability bit.

Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:19:02 -08:00
Haggai Eran
e420f0c0f3 mlx5_core: Add support for page faults events and low level handling
* Add a handler function pointer in the mlx5_core_qp struct for page
  fault events. Handle page fault events by calling the handler
  function, if not NULL.
* Add on-demand paging capability query command.
* Export command for resuming QPs after page faults.
* Add various constants related to paging support.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:18:59 -08:00
Roland Dreier
6cb7ff3dcf mlx5_core: Re-add MLX5_DEV_CAP_FLAG_ON_DMND_PG flag
In commit 0c7aac854f ("net/mlx5_core: Remove unused dev cap enum
fields"), the flag MLX5_DEV_CAP_FLAG_ON_DMND_PG was removed.
Unfortunately the on-demand paging changes actually use it, so re-add
the missing flag.

Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:18:58 -08:00
Sagi Grimberg
7dcf9c193b IB/srp: Allow newline separator for connection string
In case the last argument of the connection string is processed as a
string (destination GID for example).

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Acked-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:15:23 -08:00
Haggai Eran
882214e2b1 IB/core: Implement support for MMU notifiers regarding on demand paging regions
* Add an interval tree implementation for ODP umems. Create an
  interval tree for each ucontext (including a count of the number of
  ODP MRs in this context, semaphore, etc.), and register ODP umems in
  the interval tree.
* Add MMU notifiers handling functions, using the interval tree to
  notify only the relevant umems and underlying MRs.
* Register to receive MMU notifier events from the MM subsystem upon
  ODP MR registration (and unregister accordingly).
* Add a completion object to synchronize the destruction of ODP umems.
* Add mechanism to abort page faults when there's a concurrent invalidation.

The way we synchronize between concurrent invalidations and page
faults is by keeping a counter of currently running invalidations, and
a sequence number that is incremented whenever an invalidation is
caught. The page fault code checks the counter and also verifies that
the sequence number hasn't progressed before it updates the umem's
page tables. This is similar to what the kvm module does.

In order to prevent the case where we register a umem in the middle of
an ongoing notifier, we also keep a per ucontext counter of the total
number of active mmu notifiers. We only enable new umems when all the
running notifiers complete.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Yuval Dagan <yuvalda@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:13:36 -08:00
Shachar Raindel
8ada2c1c0c IB/core: Add support for on demand paging regions
* Extend the umem struct to keep the ODP related data.
* Allocate and initialize the ODP related information in the umem
  (page_list, dma_list) and freeing as needed in the end of the run.
* Store a reference to the process PID struct in the ucontext.  Used to
  safely obtain the task_struct and the mm during fault handling,
  without preventing the task destruction if needed.
* Add 2 helper functions: ib_umem_odp_map_dma_pages and
  ib_umem_odp_unmap_dma_pages. These functions get the DMA addresses
  of specific pages of the umem (and, currently, pin them).
* Support for page faults only - IB core will keep the reference on
  the pages used and call put_page when freeing an ODP umem
  area. Invalidations support will be added in a later patch.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Majd Dibbiny <majd@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:13:36 -08:00
Sagi Grimberg
860f10a799 IB/core: Add flags for on demand paging support
* Add a configuration option for enable on-demand paging support in
  the infiniband subsystem (CONFIG_INFINIBAND_ON_DEMAND_PAGING). In a
  later patch, this configuration option will select the MMU_NOTIFIER
  configuration option to enable mmu notifiers.
* Add a flag for on demand paging (ODP) support in the IB device capabilities.
* Add a flag to request ODP MR in the access flags to reg_mr.
* Fail registrations done with the ODP flag when the low-level driver
  doesn't support this.
* Change the conditions in which an MR will be writable to explicitly
  specify the access flags.  This is to avoid making an MR writable just
  because it is an ODP MR.
* Add a ODP capabilities to the extended query device verb.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:13:35 -08:00
Eli Cohen
5a77abf9a9 IB/core: Add support for extended query device caps
Add extensible query device capabilities verb to allow adding new features.
ib_uverbs_ex_query_device is added and copy_query_dev_fields is used to
copy capability fields to be used by both ib_uverbs_query_device and
ib_uverbs_ex_query_device.

Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:13:35 -08:00
Haggai Eran
c1395a2a8c IB/mlx5: Add function to read WQE from user-space
Add a helper function mlx5_ib_read_user_wqe to read information from
user-space owned work queues.  The function will be used in a later
patch by the page-fault handling code in mlx5_ib.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>

[ Add stub for ib_umem_copy_from() for CONFIG_INFINIBAND_USER_MEM=n
  - Roland ]

Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:13:35 -08:00
Haggai Eran
c5d76f130b IB/core: Add umem function to read data from user-space
In some drivers there's a need to read data from a user space area
that was pinned using ib_umem when running from a different process
context.

The ib_umem_copy_from function allows reading data from the physical
pages pinned in the ib_umem struct.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:13:35 -08:00
Haggai Eran
406f9e5fa9 IB/core: Replace ib_umem's offset field with a full address
In order to allow umems that do not pin memory, we need the umem to
keep track of its region's address.

This makes the offset field redundant, and so this patch removes it.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:13:35 -08:00
Haggai Eran
968e78dd96 IB/mlx5: Enhance UMR support to allow partial page table update
The current UMR interface doesn't allow partial updates to a memory
region's page tables. This patch changes the interface to allow that.

It also changes the way the UMR operation validates the memory
region's state.  When set, IB_SEND_UMR_FAIL_IF_FREE will cause the UMR
operation to fail if the MKEY is in the free state. When it is
unchecked the operation will check that it isn't in the free state.

Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:13:35 -08:00
Haggai Eran
21af2c3ebf IB/mlx5: Remove per-MR pas and dma pointers
Since UMR code now uses its own context struct on the stack, the pas
and dma pointers for the UMR operation that remained in the mlx5_ib_mr
struct are not necessary.  This patch removes them.

Fixes: a74d24168d ("IB/mlx5: Refactor UMR to have its own context struct")
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:13:35 -08:00
Devesh Sharma
e5f0508d43 RDMA/ocrdma: Always resolve destination mac from GRH for UD QPs
For user applications that use UD QPs, always resolve destination MAC
from the GRH.  This is to avoid failure due to any garbage value in
the attr->dmac.

Signed-off-by: Selvin Xavier <selvin.xavier@emulex.com>
Signed-off-by: Devesh Sharma <devesh.sharma@emulex.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:13:09 -08:00
Mitesh Ahuja
95bf0093a9 RDMA/ocrdma: Fix ocrdma_query_qp() to report q_key value for UD QPs
Signed-off-by: Mitesh Ahuja <mitesh.ahuja@emulex.com>
Signed-off-by: Devesh Sharma <devesh.sharma@emulex.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:13:09 -08:00
Yuval Shaia
0b9976577c mlx4_core: Check for DPDP violation only when DPDP is not supported
Move check for DPDP out of the loop to make the code more readable.

Signed-off-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:12:29 -08:00
Jack Morgenstein
9f35e8995b IB/mlx4: Fix an incorrectly shadowed variable in mlx4_ib_rereg_user_mr
This error was detected by sparse static checker:

    drivers/infiniband/hw/mlx4/mr.c:226:21: warning: symbol 'err' shadows an earlier one
    drivers/infiniband/hw/mlx4/mr.c:197:13: originally declared here

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:12:29 -08:00
Or Gerlitz
056da88f2e IB/iser: Bump version to 1.5
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:47 -08:00
Sagi Grimberg
5bb6e543d2 IB/iser: DIX update
Following few recent Block integrity updates, we align the iSER data
integrity offload settings with:

- Deprecate pi_guard module param
- Expose support for DIX type 0.
- Use scsi_transfer_length for the transfer length
- Get pi_interval, ref_tag, ref_remap, bg_type and
  check_mask setting from scsi_cmnd

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:46 -08:00
Sagi Grimberg
06c7fb6776 IB/iser: Micro-optimize iser_handle_wc
Use likely() for wc.status == IB_WC_SUCCESS

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:46 -08:00
Sagi Grimberg
60e20908c5 IB/iser: Micro-optimize iser logging
And fix a checkpatch warning.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:46 -08:00
Sagi Grimberg
da64bdb25b IB/iser: Use more completion queues
No reason to settle with four, can use the min between device max comp
vectors and number of cores.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:45 -08:00
Sagi Grimberg
7e1fd4d1e3 IB/iser: Remove redundant is_mr indicator
It is enough to check mem_h pointer assignment, mem_h == NULL will
indicate that buffer is not registered using mr.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:45 -08:00
Sagi Grimberg
a11b3e6935 IB/iser: Centralize memory region invalidation to a function
Eliminates code duplication.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:45 -08:00
Sagi Grimberg
f0caef6d40 IB/iser: Terminate connection before cleaning inflight tasks
When closing the connection, we should first terminate the connection
(in case it was not previously terminated) to guarantee the QP is in
error state and we are done with servicing IO. Only then go ahead with
tasks cleanup via iscsi_conn_stop.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:44 -08:00
Sagi Grimberg
7414dde0a6 IB/iser: Fix race between iser connection teardown and scsi TMFs
In certain scenarios (target kill with live IO) scsi TMFs may race
with iser RDMA teardown, which might cause NULL dereference on iser IB
device handle (which might have been freed). In this case we take a
conditional lock for TMFs and check the connection state (avoid
introducing lock contention in the IO path). This is indeed best
effort approach, but sufficient to survive multi targets sudden death
while heavy IO is inflight.

While we are on it, add a nice kernel-doc style documentation.

Reported-by: Ariel Nahum <arieln@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:44 -08:00
Ariel Nahum
3f562a0b8f IB/iser: Fix possible NULL derefernce ib_conn->device in session_create
If rdma_cm error event comes after ep_poll but before conn_bind, we
should protect against dereferncing the device (which may have been
terminated) in session_create and conn_create (already protected)
callbacks.

Signed-off-by: Ariel Nahum <arieln@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:44 -08:00
Sagi Grimberg
49df2781b1 IB/iser: Fix sparse warnings
Use uintptr_t to handle wr_id casting, which was found by Kbuild test
robot and smatch.  Also remove an internal definition of variable which
potentially shadows an external one (and make sparse happy).

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:44 -08:00
Max Gurtovoy
6ec9d4d231 IB/iser: Fix possible SQ overflow
Fix a regression was introduced in commit 6df5a128f0 ("IB/iser:
Suppress scsi command send completions").

The sig_count was wrongly set to be static variable, thus it is
possible that we won't reach to (sig_count % ISER_SIGNAL_BATCH) == 0
condition (due to races) and the send queue will be overflowed.

Instead keep sig_count per connection. We don't need it to be atomic
as we are safe under the iscsi session frwd_lock taken by libiscsi on
the queuecommand path.

Fixes: 6df5a128f0 ("IB/iser: Suppress scsi command send completions")
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:44 -08:00
Sagi Grimberg
93acb7bbc7 IB/iser: Decrement CQ's active QPs accounting when QP creation fails
When creating a connection QP we choose the least used CQ and inc the
number of active QPs on that. If we fail to create the QP, we need to
decrement the active QPs counter.

Reported-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:44 -08:00
Ariel Nahum
5426b1711f IB/iser: Collapse cleanup and disconnect handlers
No real need to wait for TIMEWAIT_EXIT before we destroy the RDMA
resources (also TIMEAWAIT_EXIT is not guarenteed to always arrive).  As
for the cma_id, only destroy it if the state is not DOWN where in this
case, conn_release is already running and we don't want to compete.

Signed-off-by: Ariel Nahum <arieln@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:44 -08:00
Sagi Grimberg
16df2a26fb IB/iser: Fix catastrophic error flow hang
In case of the HCA going into catasrophic error flow, the
beacon post_send is likely to fail, so surely there will
be no completion for it.

In this case, use a best effort approach and don't wait for beacon
completion if we failed to post the send.

Reported-by: Alex Tabachnik <alext@mellanox.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:44 -08:00
Minh Tran
f4641ef701 IB/iser: Re-adjust CQ and QP send ring sizes to HW limits
Re-adjust max CQEs per CQ and max send_wr per QP according
to the resource limits supported by underlying hardware.

Signed-off-by: Minh Tran <minhduc.tran@emulex.com>
Signed-off-by: Jayamohan Kallickal <jayamohan.kallickal@emulex.com>
Acked-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:44 -08:00
Doug Ledford
ce347ab90e IPoIB: No longer use flush as a parameter
Various places in the IPoIB code had a deadlock related to flushing
the ipoib workqueue.  Now that we have per device workqueues and a
specific flush workqueue, there is no longer a deadlock issue with
flushing the device specific workqueues and we can do so unilaterally.

Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:15 -08:00
Doug Ledford
bb42a6dd02 IPoIB: Make ipoib_mcast_stop_thread flush the workqueue
We used to pass a flush variable to mcast_stop_thread to indicate if
we should flush the workqueue or not.  This was due to some code
trying to flush a workqueue that it was currently running on which is
a no-no.  Now that we have per-device work queues, and now that
ipoib_mcast_restart_task has taken the fact that it is queued on a
single thread workqueue with all of the ipoib_mcast_join_task's and
therefore has no need to stop the join task while it runs, we can do
away with the flush parameter and unilaterally flush always.

Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:15 -08:00
Doug Ledford
5141861cd5 IPoIB: Use dedicated workqueues per interface
During my recent work on the rtnl lock deadlock in the IPoIB driver, I
saw that even once I fixed the apparent races for a single device, as
soon as that device had any children, new races popped up.  It turns
out that this is because no matter how well we protect against races
on a single device, the fact that all devices use the same workqueue,
and flush_workqueue() flushes *everything* from that workqueue, we can
have one device in the middle of a down and holding the rtnl lock and
another totally unrelated device needing to run mcast_restart_task,
which wants the rtnl lock and will loop trying to take it unless is
sees its own FLAG_ADMIN_UP flag go away.  Because the unrelated
interface will never see its own ADMIN_UP flag drop, the interface
going down will deadlock trying to flush the queue.  There are several
possible solutions to this problem:

Make carrier_on_task and mcast_restart_task try to take the rtnl for
some set period of time and if they fail, then bail.  This runs the
real risk of dropping work on the floor, which can end up being its
own separate kind of deadlock.

Set some global flag in the driver that says some device is in the
middle of going down, letting all tasks know to bail.  Again, this can
drop work on the floor.  I suppose if our own ADMIN_UP flag doesn't go
away, then maybe after a few tries on the rtnl lock we can queue our
own task back up as a delayed work and return and avoid dropping work
on the floor that way.  But I'm not 100% convinced that we won't cause
other problems.

Or the method this patch attempts to use, which is when we bring an
interface up, create a workqueue specifically for that interface, so
that when we take it back down, we are flushing only those tasks
associated with our interface.  In addition, keep the global
workqueue, but now limit it to only flush tasks.  In this way, the
flush tasks can always flush the device specific work queues without
having deadlock issues.

Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:15 -08:00
Doug Ledford
3bcce487fd IPoIB: change init sequence ordering
In preparation for using per device work queues, we need to move the
start of the neighbor thread task to after ipoib_ib_dev_init and move
the destruction of the neighbor task to before ipoib_ib_dev_cleanup.
Otherwise we will end up freeing our workqueue with work possibly
still on it.

Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:15 -08:00
Doug Ledford
e5d1dcf1b0 IPoIB: fix mcast_dev_flush/mcast_restart_task race
Our mcast_dev_flush routine and our mcast_restart_task can race
against each other.  In particular, they both hold the priv->lock
while manipulating the rbtree and while removing mcast entries from
the multicast_list and while adding entries to the remove_list, but
they also both drop their locks prior to doing the actual removes.
The mcast_dev_flush routine is run entirely under the rtnl lock and so
has at least some locking.  The actual race condition is like this:

Thread 1                                Thread 2
ifconfig ib0 up
  start multicast join for broadcast
  multicast join completes for broadcast
  start to add more multicast joins
    call mcast_restart_task to add new entries
                                        ifconfig ib0 down
					  mcast_dev_flush
					    mcast_leave(mcast A)
    mcast_leave(mcast A)

As mcast_leave calls ib_sa_multicast_leave, and as member in
core/multicast.c is ref counted, we run into an unbalanced refcount
issue.  To avoid stomping on each others removes, take the rtnl lock
specifically when we are deleting the entries from the remove list.

Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:14 -08:00
Doug Ledford
016d9fb25c IPoIB: fix MCAST_FLAG_BUSY usage
Commit a9c8ba5884 ("IPoIB: Fix usage of uninitialized multicast
objects") added a new flag MCAST_JOIN_STARTED, but was not very strict
in how it was used.  We didn't always initialize the completion struct
before we set the flag, and we didn't always call complete on the
completion struct from all paths that complete it.  This made it less
than totally effective, and certainly made its use confusing.  And in
the flush function we would use the presence of this flag to signal
that we should wait on the completion struct, but we never cleared
this flag, ever.  This is further muddied by the fact that we overload
the MCAST_FLAG_BUSY flag to mean two different things: we have a join
in flight, and we have succeeded in getting an ib_sa_join_multicast.

In order to make things clearer and aid in resolving the rtnl deadlock
bug I've been chasing, I cleaned this up a bit.

 1) Remove the MCAST_JOIN_STARTED flag entirely
 2) Un-overload MCAST_FLAG_BUSY so it now only means a join is in-flight
 3) Test on mcast->mc directly to see if we have completed
    ib_sa_join_multicast (using IS_ERR_OR_NULL)
 4) Make sure that before setting MCAST_FLAG_BUSY we always initialize
    the mcast->done completion struct
 5) Make sure that before calling complete(&mcast->done), we always clear
    the MCAST_FLAG_BUSY bit
 6) Take the mcast_mutex before we call ib_sa_multicast_join and also
    take the mutex in our join callback.  This forces
    ib_sa_multicast_join to return and set mcast->mc before we process
    the callback.  This way, our callback can safely clear mcast->mc
    if there is an error on the join and we will do the right thing as
    a result in mcast_dev_flush.
 7) Because we need the mutex to synchronize mcast->mc, we can no
    longer call mcast_sendonly_join directly from mcast_send and
    instead must add sendonly join processing to the mcast_join_task

A number of different races are resolved with these changes.  These
races existed with the old MCAST_FLAG_BUSY usage, the
MCAST_JOIN_STARTED flag was an attempt to address them, and while it
helped, a determined effort could still trip things up.

One race looks something like this:

Thread 1                             Thread 2
ib_sa_join_multicast (as part of running restart mcast task)
  alloc member
  call callback
                                     ifconfig ib0 down
				     wait_for_completion
    callback call completes
                                     wait_for_completion in
				     mcast_dev_flush completes
				       mcast->mc is PTR_ERR_OR_NULL
				       so we skip ib_sa_leave_multicast
    return from callback
  return from ib_sa_join_multicast
set mcast->mc = return from ib_sa_multicast

We now have a permanently unbalanced join/leave issue that trips up the
refcounting in core/multicast.c

Another like this:

Thread 1                   Thread 2         Thread 3
ib_sa_multicast_join
                                            ifconfig ib0 down
					    priv->broadcast = NULL
                           join_complete
			                    wait_for_completion
			   mcast->mc is not yet set, so don't clear
return from ib_sa_join_multicast and set mcast->mc
			   complete
			   return -EAGAIN (making mcast->mc invalid)
			   		    call ib_sa_multicast_leave
					    on invalid mcast->mc, hang
					    forever

By holding the mutex around ib_sa_multicast_join and taking the mutex
early in the callback, we force mcast->mc to be valid at the time we
run the callback.  This allows us to clear mcast->mc if there is an
error and the join is going to fail.  We do this before we complete
the mcast.  In this way, mcast_dev_flush always sees consistent state
in regards to mcast->mc membership at the time that the
wait_for_completion() returns.

Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:14 -08:00
Doug Ledford
67d7209e1f IPoIB: Make the carrier_on_task race aware
We blindly assume that we can just take the rtnl lock and that will
prevent races with downing this interface.  Unfortunately, that's not
the case.  In ipoib_mcast_stop_thread() we will call flush_workqueue()
in an attempt to clear out all remaining instances of ipoib_join_task.
But, since this task is put on the same workqueue as the join task,
the flush_workqueue waits on this thread too.  But this thread is
deadlocked on the rtnl lock.  The better thing here is to use trylock
and loop on that until we either get the lock or we see that
FLAG_ADMIN_UP has been cleared, in which case we don't need to do
anything anyway and we just return.

Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:14 -08:00
Doug Ledford
afe1de664e IPoIB: Consolidate rtnl_lock tasks in workqueue
Setting the MTU can safely be moved to the carrier_on_task, which keeps
us from needing to take the rtnl lock in the join_finish section.

Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:11:14 -08:00
Hariprasad S
e6b11163d4 RDMA/cxgb4: Handle NET_XMIT return codes
cxgb4_create_server() and cxgb4_create_server6() return NET_XMIT_*
values or a negative errno. iw_cxgb4 need to handle this correctly.

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:10:46 -08:00
Steve Wise
5b34180883 RDMA/cxgb4: Wake up waiters after flushing the qp
When transitioning into ERROR state, the QP was getting flushed after
waking up any waiters.  This can cause applications to miss flushed work
requests which can stall an NFS mount.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2014-12-15 18:10:46 -08:00