From: Nicholas Bellinger Date: Fri, 20 May 2011 03:19:11 +0000 (-0700) Subject: target: Fix bug with task_sg chained transport_free_dev_tasks release X-Git-Url: http://git.alex.org.uk target: Fix bug with task_sg chained transport_free_dev_tasks release BugLink: http://bugs.launchpad.net/bugs/793702 commit f436677262a5b524ac87675014c6d4e8ee153029 upstream. This patch addresses a bug in the target core release path for HW operation where transport_free_dev_tasks() was incorrectly being called from transport_lun_remove_cmd() while releasing a se_cmd reference and calling struct target_core_fabric_ops->queue_data_in(). This would result in a OOPs with HW target mode when the release of se_task->task_sg[] would happen before pci_unmap_sg() can be called in HW target mode fabric module code. This patch addresses the issue by moving transport_free_dev_tasks() from transport_lun_remove_cmd() into transport_generic_free_cmd(), and adding TRANSPORT_FREE_CMD_INTR and transport_generic_free_cmd_intr() to allow se_cmd descriptor release to happen fromfrom within transport_processing_thread() process context when release of se_cmd is not possible from HW interrupt context. Signed-off-by: Nicholas Bellinger Signed-off-by: James Bottomley Signed-off-by: Greg Kroah-Hartman Signed-off-by: Tim Gardner --- diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index a0ad2f4..0ddcc26 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -765,7 +765,6 @@ static void transport_lun_remove_cmd(struct se_cmd *cmd) transport_all_task_dev_remove_state(cmd); spin_unlock_irqrestore(&T_TASK(cmd)->t_state_lock, flags); - transport_free_dev_tasks(cmd); check_lun: spin_lock_irqsave(&lun->lun_cmd_lock, flags); @@ -2062,6 +2061,13 @@ int transport_generic_handle_tmr( } EXPORT_SYMBOL(transport_generic_handle_tmr); +void transport_generic_free_cmd_intr( + struct se_cmd *cmd) +{ + transport_add_cmd_to_queue(cmd, TRANSPORT_FREE_CMD_INTR); +} +EXPORT_SYMBOL(transport_generic_free_cmd_intr); + static int transport_stop_tasks_for_cmd(struct se_cmd *cmd) { struct se_task *task, *task_tmp; @@ -5302,6 +5308,8 @@ void transport_generic_free_cmd( if (wait_for_tasks && cmd->transport_wait_for_tasks) cmd->transport_wait_for_tasks(cmd, 0, 0); + transport_free_dev_tasks(cmd); + transport_generic_remove(cmd, release_to_pool, session_reinstatement); } @@ -6142,6 +6150,9 @@ get_cmd: case TRANSPORT_REMOVE: transport_generic_remove(cmd, 1, 0); break; + case TRANSPORT_FREE_CMD_INTR: + transport_generic_free_cmd(cmd, 0, 1, 0); + break; case TRANSPORT_PROCESS_TMR: transport_generic_do_tmr(cmd); break; diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index 0828b6c..95c9d98 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -98,6 +98,7 @@ enum transport_state_table { TRANSPORT_REMOVE = 14, TRANSPORT_FREE = 15, TRANSPORT_NEW_CMD_MAP = 16, + TRANSPORT_FREE_CMD_INTR = 17, }; /* Used for struct se_cmd->se_cmd_flags */ diff --git a/include/target/target_core_transport.h b/include/target/target_core_transport.h index 2e8ec51..379ae61 100644 --- a/include/target/target_core_transport.h +++ b/include/target/target_core_transport.h @@ -170,6 +170,7 @@ extern int transport_generic_handle_cdb_map(struct se_cmd *); extern int transport_generic_handle_data(struct se_cmd *); extern void transport_new_cmd_failure(struct se_cmd *); extern int transport_generic_handle_tmr(struct se_cmd *); +extern void transport_generic_free_cmd_intr(struct se_cmd *); extern void __transport_stop_task_timer(struct se_task *, unsigned long *); extern unsigned char transport_asciihex_to_binaryhex(unsigned char val[2]); extern int transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *, u32,