Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759395AbcCVLHP (ORCPT ); Tue, 22 Mar 2016 07:07:15 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56754 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758789AbcCVKmb (ORCPT ); Tue, 22 Mar 2016 06:42:31 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Quinn Tran , Himanshu Madhani , Sagi Grimberg , Christoph Hellwig , Hannes Reinecke , Andy Grover , Mike Christie , Nicholas Bellinger , Luis Henriques Subject: [PATCH 3.16.y-ckt 075/142] target: Fix race with SCF_SEND_DELAYED_TAS handling Date: Tue, 22 Mar 2016 10:40:04 +0000 Message-Id: <1458643271-4227-76-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1458643271-4227-1-git-send-email-luis.henriques@canonical.com> References: <1458643271-4227-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4856 Lines: 144 3.16.7-ckt26 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Nicholas Bellinger commit 310d3d314be7f0a84011ebdc4bdccbcae9755a87 upstream. This patch fixes a race between setting of SCF_SEND_DELAYED_TAS in transport_send_task_abort(), and check of the same bit in transport_check_aborted_status(). It adds a __transport_check_aborted_status() version that is used by target_execute_cmd() when se_cmd->t_state_lock is held, and a transport_check_aborted_status() wrapper for all other existing callers. Also, it handles the case where the check happens before transport_send_task_abort() gets called. For this, go ahead and set SCF_SEND_DELAYED_TAS early when necessary, and have transport_send_task_abort() send the abort. Cc: Quinn Tran Cc: Himanshu Madhani Cc: Sagi Grimberg Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Andy Grover Cc: Mike Christie Signed-off-by: Nicholas Bellinger [ luis: backported to 3.16: based on Nicholas' backport to 3.14 ] Signed-off-by: Luis Henriques --- drivers/target/target_core_transport.c | 55 ++++++++++++++++++++++++++-------- 1 file changed, 42 insertions(+), 13 deletions(-) diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 3128b718ff73..f787e53e12e8 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1758,19 +1758,21 @@ static bool target_handle_task_attr(struct se_cmd *cmd) return true; } +static int __transport_check_aborted_status(struct se_cmd *, int); + void target_execute_cmd(struct se_cmd *cmd) { /* - * If the received CDB has aleady been aborted stop processing it here. - */ - if (transport_check_aborted_status(cmd, 1)) - return; - - /* * Determine if frontend context caller is requesting the stopping of * this command for frontend exceptions. + * + * If the received CDB has aleady been aborted stop processing it here. */ spin_lock_irq(&cmd->t_state_lock); + if (__transport_check_aborted_status(cmd, 1)) { + spin_unlock_irq(&cmd->t_state_lock); + return; + } if (cmd->transport_state & CMD_T_STOP) { pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08x\n", __func__, __LINE__, @@ -2951,28 +2953,50 @@ after_reason: } EXPORT_SYMBOL(transport_send_check_condition_and_sense); -int transport_check_aborted_status(struct se_cmd *cmd, int send_status) +static int __transport_check_aborted_status(struct se_cmd *cmd, int send_status) + __releases(&cmd->t_state_lock) + __acquires(&cmd->t_state_lock) { + assert_spin_locked(&cmd->t_state_lock); + WARN_ON_ONCE(!irqs_disabled()); + if (!(cmd->transport_state & CMD_T_ABORTED)) return 0; - /* * If cmd has been aborted but either no status is to be sent or it has * already been sent, just return */ - if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS)) + if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS)) { + if (send_status) + cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS; return 1; + } - pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB: 0x%02x ITT: 0x%08x\n", - cmd->t_task_cdb[0], cmd->se_tfo->get_task_tag(cmd)); + pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB:" + " 0x%02x ITT: 0x%08x\n", cmd->t_task_cdb[0], + cmd->se_tfo->get_task_tag(cmd)); cmd->se_cmd_flags &= ~SCF_SEND_DELAYED_TAS; cmd->scsi_status = SAM_STAT_TASK_ABORTED; trace_target_cmd_complete(cmd); + + spin_unlock_irq(&cmd->t_state_lock); cmd->se_tfo->queue_status(cmd); + spin_lock_irq(&cmd->t_state_lock); return 1; } + +int transport_check_aborted_status(struct se_cmd *cmd, int send_status) +{ + int ret; + + spin_lock_irq(&cmd->t_state_lock); + ret = __transport_check_aborted_status(cmd, send_status); + spin_unlock_irq(&cmd->t_state_lock); + + return ret; +} EXPORT_SYMBOL(transport_check_aborted_status); void transport_send_task_abort(struct se_cmd *cmd) @@ -2994,12 +3018,17 @@ void transport_send_task_abort(struct se_cmd *cmd) */ if (cmd->data_direction == DMA_TO_DEVICE) { if (cmd->se_tfo->write_pending_status(cmd) != 0) { - cmd->transport_state |= CMD_T_ABORTED; + spin_lock_irqsave(&cmd->t_state_lock, flags); + if (cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS) { + spin_unlock_irqrestore(&cmd->t_state_lock, flags); + goto send_abort; + } cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS; - smp_mb__after_atomic(); + spin_unlock_irqrestore(&cmd->t_state_lock, flags); return; } } +send_abort: cmd->scsi_status = SAM_STAT_TASK_ABORTED; transport_lun_remove_cmd(cmd);