Commit Graph

7 Commits

Author SHA1 Message Date
Roland Dreier d5627acba9 iscsi-target: Fix missed wakeup race in TX thread
The sleeping code in iscsi_target_tx_thread() is susceptible to the classic
missed wakeup race:

 - TX thread finishes handle_immediate_queue() and handle_response_queue(),
   thinks both queues are empty.
 - Another thread adds a queue entry and does wake_up_process(), which does
   nothing because the TX thread is still awake.
 - TX thread does schedule_timeout() and sleeps forever.

In practice this can kill an iSCSI connection if for example an initiator
does single-threaded writes and the target misses the wakeup window when
queueing an R2T; in this case the connection will be stuck until the
initiator loses patience and does some task management operation (or kills
the connection entirely).

Fix this by converting to wait_event_interruptible(), which does not
suffer from this sort of race.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: Andy Grover <agrover@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-11-01 00:38:44 -07:00
Christoph Hellwig 50e5c87de4 iscsit: proper endianess conversions
Make sure all on the wire types are use as big endian and big endian only so
that sparse can verify all the conversions are done right.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-10-03 14:39:22 -07:00
Christoph Hellwig 66c7db6876 iscsit: use the itt_t abstract type
Use the special itt_t type defined by the iscsi headers and the initiator
to make sure it's an opaque value.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-10-03 14:21:50 -07:00
Andy Grover 4334e49bca target/iscsi: Fold _decide_list_to_build into _build_pdu_and_seq_lists
Rename iscsit_build_pdu_and_seq_list to iscsit_do_build_pdu_and_seq_lists

Rename iscsit_do_build_list to iscsit_build_pdu_and_seq_lists

Move code from iscsit_decide_list_to_build into _seq_pdu_list.c, seems
a better fit.

Also update some comments in pdu/seq code for correctness and whitespace.

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-04-14 17:40:38 -07:00
Andy Grover d28b11692e target/iscsi: Inline iscsit_allocate_se_cmd and *_for_tmr
Trying to move a bunch of stuff around so iscsi can use target_submit_cmd
someday, and so stuff needs to be in that function directly instead of
hidden, so it can be reordered etc.

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-04-14 17:40:37 -07:00
Nicholas Bellinger d270190a75 iscsi-target: Remove SCF_SE_LUN_CMD flag abuses
This patch removes a number of SCF_SE_LUN_CMD flag abuses within iscsi-target
code to determine when iscsit_release_cmd() or transport_generic_free_cmd()
should be called while releasing an individual iscsi_cmd descriptor.

In the place of SCF_SE_LUN_CMD checks, this patch converts existing code to
use a new iscsit_free_cmd() that inspects iscsi_cmd->iscsi_opcode types to
determine which of the above functions should be invoked.  It also removes the
now unnecessary special case checking in iscsit_release_commands_from_conn().

(hch: Use iscsit_free_cmd instead of open-coded alternative)

Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2011-10-24 03:20:56 +00:00
Nicholas Bellinger e48354ce07 iscsi-target: Add iSCSI fabric support for target v4.1
The Linux-iSCSI.org target module is a full featured in-kernel
software implementation of iSCSI target mode (RFC-3720) for the
current WIP mainline target v4.1 infrastructure code for the v3.1
kernel.  More information can be found here:

http://linux-iscsi.org/wiki/ISCSI

This includes support for:

   * RFC-3720 defined request / response state machines and support for
     all defined iSCSI operation codes from Section 10.2.1.2 using libiscsi
     include/scsi/iscsi_proto.h PDU definitions
   * Target v4.1 compatible control plane using the generic layout in
     target_core_fabric_configfs.c and fabric dependent attributes
     within /sys/kernel/config/target/iscsi/ subdirectories.
   * Target v4.1 compatible iSCSI statistics based on RFC-4544 (iSCSI MIBS)
   * Support for IPv6 and IPv4 network portals in M:N mapping to TPGs
   * iSCSI Error Recovery Hierarchy support
   * Per iSCSI connection RX/TX thread pair scheduling affinity
   * crc32c + crc32c_intel SSEv4 instruction offload support using libcrypto
   * CHAP Authentication support using libcrypto
   * Conversion to use internal SGl allocation with iscsit_alloc_buffs() ->
     transport_generic_map_mem_to_cmd()

(nab: Fix iscsi_proto.h struct scsi_lun usage from linux-next in commit:
      iscsi: Use struct scsi_lun in iscsi structs instead of u8[8])
(nab: Fix 32-bit compile warnings)

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andy Grover <agrover@redhat.com>
Acked-by: Roland Dreier <roland@kernel.org>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
2011-07-26 09:16:43 +00:00