From dd8ae59d48790d5c25f47ebbe502c8ca379fdde0 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Sat, 30 Jul 2011 05:03:58 -0700 Subject: target: Fix bug for transport_generic_wait_for_tasks with direct operation This patch fixes a bug in transport_handle_cdb_direct() usage with target_core where transport_generic_wait_for_tasks() was bypassing active I/O + usage of cmd->t_transport_stop_comp because cmd->t_transport_active=1 was not being set before dispatching with transport_generic_new_cmd(). The fix follows existing usage in transport_generic_handle_cdb*() -> transport_add_cmd_to_queue() and set these directly, as well as handle transport_generic_new_cmd() exceptions for QUEUE_FULL and CHECK_CONDITION instead of propigating up to RX context fabric code. The bug was manifesting itself with the following SLUB poison overwritten warnings with iscsi-target v4.1 LUNs using the new process context direct operation during session reinstatement with active I/O exception handling: [885410.498267] ============================================================================= [885410.621622] BUG lio_cmd_cache: Poison overwritten [885410.621791] ----------------------------------------------------------------------------- [885410.621792] [885410.623420] INFO: 0xffff880000cf3750-0xffff880000cf378d. First byte 0x6a instead of 0x6b [885410.626332] INFO: Allocated in iscsit_allocate_cmd+0x1c/0xd4 [iscsi_target_mod] age=345 cpu=1 pid=22554 [885411.855189] INFO: Freed in iscsit_release_cmd+0x208/0x217 [iscsi_target_mod] age=1410 cpu=1 pid=22554 [885411.856048] INFO: Slab 0xffffea000002d480 objects=22 used=0 fp=0xffff880000cf7300 flags=0x4080 [885411.856368] INFO: Object 0xffff880000cf33c0 @offset=13248 fp=0xffff880000cf6780 [885411.955678] Pid: 22554, comm: iscsi_trx Not tainted 3.0.0-rc7+ #30 [885411.956040] Call Trace: [885411.957029] [] print_trailer+0x12e/0x137 [885412.752879] [] check_bytes_and_report+0xb9/0xfd [885412.754933] [] check_object+0xb5/0x192 [885412.755099] [] __free_slab+0x96/0x13a [885412.757008] [] discard_slab+0x41/0x43 [885412.758171] [] __slab_free+0xf3/0xfe [885412.761027] [] ? iscsit_release_cmd+0x208/0x217 [iscsi_target_mod] [885412.761354] [] kmem_cache_free+0x6f/0xac [885412.761536] [] iscsit_release_cmd+0x208/0x217 [iscsi_target_mod] [885412.762056] [] ? iblock_free_task+0x34/0x39 [target_core_iblock] [885412.762368] [] lio_release_cmd+0x10/0x12 [iscsi_target_mod] [885412.764129] [] transport_release_cmd+0x2f/0x33 [target_core_mod] [885412.805024] [] transport_generic_remove+0xb6/0xc3 [target_core_mod] [885412.806424] [] ? try_to_wake_up+0x1bd/0x1bd [885412.809033] [] transport_generic_free_cmd+0x75/0x7d [target_core_mod] [885412.810066] [] transport_generic_wait_for_tasks+0x21c/0x22b [target_core_mod] [885412.811056] [] ? mutex_lock+0x11/0x32 [885412.813059] [] ? mutex_lock+0x11/0x32 [885412.813200] [] iscsit_close_connection+0x1d5/0x63a [iscsi_target_mod] [885412.813517] [] iscsit_take_action_for_connection_exit+0xdb/0xe0 [iscsi_target_mod] [885412.813851] [] iscsi_target_rx_thread+0x11f6/0x1221 [iscsi_target_mod] [885412.829024] [] ? pick_next_task_fair+0xbe/0x10e [885412.831010] [] ? iscsit_handle_scsi_cmd+0x91d/0x91d [iscsi_target_mod] [885412.833011] [] ? iscsit_handle_scsi_cmd+0x91d/0x91d [iscsi_target_mod] [885412.835010] [] kthread+0x7d/0x85 [885412.837022] [] kernel_thread_helper+0x4/0x10 [885412.838008] [] ? kthread_worker_fn+0x145/0x145 [885412.840047] [] ? gs_change+0x13/0x13 [885412.842007] FIX lio_cmd_cache: Restoring 0xffff880000cf3750-0xffff880000cf378d=0x6 Cc: Christoph Hellwig Cc: Andy Grover Signed-off-by: Nicholas Bellinger --- drivers/target/target_core_transport.c | 31 +++++++++++++++++++++++++++++-- 1 file changed, 29 insertions(+), 2 deletions(-) (limited to 'drivers/target') diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index ff7fcf8366a0..89760329d5d0 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1747,6 +1747,8 @@ int transport_generic_handle_cdb( } EXPORT_SYMBOL(transport_generic_handle_cdb); +static void transport_generic_request_failure(struct se_cmd *, + struct se_device *, int, int); /* * Used by fabric module frontends to queue tasks directly. * Many only be used from process context only @@ -1754,6 +1756,8 @@ EXPORT_SYMBOL(transport_generic_handle_cdb); int transport_handle_cdb_direct( struct se_cmd *cmd) { + int ret; + if (!cmd->se_lun) { dump_stack(); pr_err("cmd->se_lun is NULL\n"); @@ -1765,8 +1769,31 @@ int transport_handle_cdb_direct( " from interrupt context\n"); return -EINVAL; } - - return transport_generic_new_cmd(cmd); + /* + * Set TRANSPORT_NEW_CMD state and cmd->t_transport_active=1 following + * transport_generic_handle_cdb*() -> transport_add_cmd_to_queue() + * in existing usage to ensure that outstanding descriptors are handled + * correctly during shutdown via transport_generic_wait_for_tasks() + * + * Also, we don't take cmd->t_state_lock here as we only expect + * this to be called for initial descriptor submission. + */ + cmd->t_state = TRANSPORT_NEW_CMD; + atomic_set(&cmd->t_transport_active, 1); + /* + * transport_generic_new_cmd() is already handling QUEUE_FULL, + * so follow TRANSPORT_NEW_CMD processing thread context usage + * and call transport_generic_request_failure() if necessary.. + */ + ret = transport_generic_new_cmd(cmd); + if (ret == -EAGAIN) + return 0; + else if (ret < 0) { + cmd->transport_error_status = ret; + transport_generic_request_failure(cmd, NULL, 0, + (cmd->data_direction != DMA_TO_DEVICE)); + } + return 0; } EXPORT_SYMBOL(transport_handle_cdb_direct); -- cgit v1.2.3