[PATCH 5.3 159/180] scsi: qla2xxx: Fix a race condition between aborting and completing a SCSI command

Greg Kroah-Hartman
2019-12-16T18:29:14Z

From: Bart Van Assche <bvanassche@acm.org>

[ Upstream commit 85cffefa09e448906a6f0bc20f422d75a18675bd ]

Instead of allocating a struct srb dynamically from inside .queuecommand(),
set qla2xxx_driver_template.cmd_size such that struct scsi_cmnd and struct
srb are contiguous. Do not call QLA_QPAIR_MARK_BUSY() /
QLA_QPAIR_MARK_NOT_BUSY() for SRBs associated with SCSI commands. That is
safe because scsi_remove_host() is called before queue pairs are deleted
and scsi_remove_host() waits for all outstanding SCSI commands to finish.

Cc: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Himanshu Madhani <hmadhani@marvell.com>
Reviewed-by: Himanshu Madhani <hmadhani@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/qla2xxx/qla_def.h | 1 -
drivers/scsi/qla2xxx/qla_os.c | 45 ++++++----------------------------
2 files changed, 8 insertions(+), 38 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index 0eb1d5a790b26..ea1728fe2c768 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -562,7 +562,6 @@ typedef struct srb {
} srb_t;

#define GET_CMD_SP(sp) (sp->u.scmd.cmd)
-#define SET_CMD_SP(sp, cmd) (sp->u.scmd.cmd = cmd)
#define GET_CMD_CTX_SP(sp) (sp->u.scmd.ctx)

#define GET_CMD_SENSE_LEN(sp) \
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 484045e4d194f..3aa2dd43945bf 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -727,7 +727,6 @@ qla2x00_sp_compl(void *ptr, int res)
cmd->scsi_done(cmd);
if (comp)
complete(comp);
- qla2x00_rel_sp(sp);
}

void
@@ -832,7 +831,6 @@ qla2xxx_qpair_sp_compl(void *ptr, int res)
cmd->scsi_done(cmd);
if (comp)
complete(comp);
- qla2xxx_rel_qpair_sp(sp->qpair, sp);
}

static int
@@ -925,9 +923,8 @@ qla2xxx_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
else
goto qc24_target_busy;

- sp = qla2x00_get_sp(vha, fcport, GFP_ATOMIC);
- if (!sp)
- goto qc24_host_busy;
+ sp = scsi_cmd_priv(cmd);
+ qla2xxx_init_sp(sp, vha, vha->hw->base_qpair, fcport);

sp->u.scmd.cmd = cmd;
sp->type = SRB_SCSI_CMD;
@@ -948,9 +945,6 @@ qla2xxx_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
qc24_host_busy_free_sp:
sp->free(sp);

-qc24_host_busy:
- return SCSI_MLQUEUE_HOST_BUSY;
-
qc24_target_busy:
return SCSI_MLQUEUE_TARGET_BUSY;

@@ -1011,9 +1005,8 @@ qla2xxx_mqueuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd,
else
goto qc24_target_busy;

- sp = qla2xxx_get_qpair_sp(vha, qpair, fcport, GFP_ATOMIC);
- if (!sp)
- goto qc24_host_busy;
+ sp = scsi_cmd_priv(cmd);
+ qla2xxx_init_sp(sp, vha, qpair, fcport);

sp->u.scmd.cmd = cmd;
sp->type = SRB_SCSI_CMD;
@@ -1037,9 +1030,6 @@ qla2xxx_mqueuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd,
qc24_host_busy_free_sp:
sp->free(sp);

-qc24_host_busy:
- return SCSI_MLQUEUE_HOST_BUSY;
-
qc24_target_busy:
return SCSI_MLQUEUE_TARGET_BUSY;

@@ -1280,10 +1270,8 @@ qla2xxx_eh_abort(struct scsi_cmnd *cmd)
int ret;
unsigned int id;
uint64_t lun;
- unsigned long flags;
int rval;
struct qla_hw_data *ha = vha->hw;
- struct qla_qpair *qpair;

if (qla2x00_isp_reg_stat(ha)) {
ql_log(ql_log_info, vha, 0x8042,
@@ -1295,29 +1283,11 @@ qla2xxx_eh_abort(struct scsi_cmnd *cmd)
if (ret != 0)
return ret;

- sp = (srb_t *) CMD_SP(cmd);
- if (!sp)
- return SUCCESS;
+ sp = scsi_cmd_priv(cmd);

- qpair = sp->qpair;
- if (!qpair)
- return SUCCESS;
-
- spin_lock_irqsave(qpair->qp_lock_ptr, flags);
- if (sp->type != SRB_SCSI_CMD || GET_CMD_SP(sp) != cmd) {
- /* there's a chance an interrupt could clear
- the ptr as part of done & free */
- spin_unlock_irqrestore(qpair->qp_lock_ptr, flags);
- return SUCCESS;
- }
-
- /* Get a reference to the sp and drop the lock. */
- if (sp_get(sp)){
- /* ref_count is already 0 */
- spin_unlock_irqrestore(qpair->qp_lock_ptr, flags);
+ /* Return if the command has already finished. */
+ if (sp_get(sp))
return SUCCESS;
- }
- spin_unlock_irqrestore(qpair->qp_lock_ptr, flags);

id = cmd->device->id;
lun = cmd->device->lun;
@@ -7197,6 +7167,7 @@ struct scsi_host_template qla2xxx_driver_template = {

.supported_mode = MODE_INITIATOR,
.track_queue_depth = 1,
+ .cmd_size = sizeof(srb_t),
};

static const struct pci_error_handlers qla2xxx_err_handler = {
--
2.20.1