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[SCSI] target: Fix bug with task_sg chained transport_free_dev_tasks release 

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 <nab@linux-iscsi.org>
Cc: stable@kernel.org
Signed-off-by: James Bottomley <jbottomley@parallels.com>
This commit is contained in:
Nicholas Bellinger 2011-05-19 20:19:11 -07:00 committed by James Bottomley
parent 53ab6709b4
commit f436677262
3 changed files with 14 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/target/target_core_transport.c
View File

@ -762,7 +762,6 @@ 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);
@ -2058,6 +2057,13 @@ 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;
@ -5301,6 +5307,8 @@ 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);
}
@ -6136,6 +6144,9 @@ static int transport_processing_thread(void *param)
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;

1
include/target/target_core_base.h
View File

@ -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 */

1
include/target/target_core_transport.h
View File

@ -172,6 +172,7 @@ 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,