[SCSI] libsas: close error handling vs sas_ata_task_done() race

Since sas_ata does not implement ->freeze(), completions for scmds and
internal commands can still arrive concurrent with
ata_scsi_cmd_error_handler() and sas_ata_post_internal() respectively.
By the time either of those is called libata has committed to completing
the qc, and the ATA_PFLAG_FROZEN flag tells sas_ata_task_done() it has
lost the race.

In the sas_ata_post_internal() case we take on the additional
responsibility of freeing the sas_task to close the race with
sas_ata_task_done() freeing the the task while sas_ata_post_internal()
is in the process of invoking ->lldd_abort_task().

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h
index 9c13a5c0bb3a..10eb2ea74431 100644
--- a/include/scsi/libsas.h
+++ b/include/scsi/libsas.h
@@ -662,7 +662,6 @@ void sas_unregister_dev(struct asd_sas_port *port, struct domain_device *);
 void sas_init_dev(struct domain_device *);
 
 void sas_task_abort(struct sas_task *);
-int __sas_task_abort(struct sas_task *);
 int sas_eh_device_reset_handler(struct scsi_cmnd *cmd);
 int sas_eh_bus_reset_handler(struct scsi_cmnd *cmd);