[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>
This commit is contained in:
Dan Williams
2011-11-28 12:08:22 -08:00
committed by James Bottomley
parent e500a34b02
commit 3dff5721e4
3 changed files with 75 additions and 54 deletions

View File

@@ -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);