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mpt3sas: Eliminate conditional locking in mpt3sas_scsih_issue_tm()
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This flag that conditionally acquires the mutex is confusing and prone
to bugginess: refactor it into two separate function calls, and make the
unlocked one complain if it's called outside the mutex.

Signed-off-by: Calvin Owens <calvinowens@fb.com>
Acked-by: Chaitra P B <chaitra.basappa@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Calvin Owens authored and Martin K. Petersen committed Aug 9, 2016
1 parent 310c8e4 commit 9690283
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Showing 3 changed files with 38 additions and 49 deletions.
16 changes: 5 additions & 11 deletions drivers/scsi/mpt3sas/mpt3sas_base.h
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Original file line number Diff line number Diff line change
Expand Up @@ -794,16 +794,6 @@ struct reply_post_struct {
dma_addr_t reply_post_free_dma;
};

/**
* enum mutex_type - task management mutex type
* @TM_MUTEX_OFF: mutex is not required becuase calling function is acquiring it
* @TM_MUTEX_ON: mutex is required
*/
enum mutex_type {
TM_MUTEX_OFF = 0,
TM_MUTEX_ON = 1,
};

typedef void (*MPT3SAS_FLUSH_RUNNING_CMDS)(struct MPT3SAS_ADAPTER *ioc);
/**
* struct MPT3SAS_ADAPTER - per adapter struct
Expand Down Expand Up @@ -1291,7 +1281,11 @@ void mpt3sas_scsih_reset_handler(struct MPT3SAS_ADAPTER *ioc, int reset_phase);

int mpt3sas_scsih_issue_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle,
uint channel, uint id, uint lun, u8 type, u16 smid_task,
ulong timeout, enum mutex_type m_type);
ulong timeout);
int mpt3sas_scsih_issue_locked_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle,
uint channel, uint id, uint lun, u8 type, u16 smid_task,
ulong timeout);

void mpt3sas_scsih_set_tm_flag(struct MPT3SAS_ADAPTER *ioc, u16 handle);
void mpt3sas_scsih_clear_tm_flag(struct MPT3SAS_ADAPTER *ioc, u16 handle);
void mpt3sas_expander_remove(struct MPT3SAS_ADAPTER *ioc, u64 sas_address);
Expand Down
5 changes: 2 additions & 3 deletions drivers/scsi/mpt3sas/mpt3sas_ctl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1001,10 +1001,9 @@ _ctl_do_mpt_command(struct MPT3SAS_ADAPTER *ioc, struct mpt3_ioctl_command karg,
ioc->name,
le16_to_cpu(mpi_request->FunctionDependent1));
mpt3sas_halt_firmware(ioc);
mpt3sas_scsih_issue_tm(ioc,
mpt3sas_scsih_issue_locked_tm(ioc,
le16_to_cpu(mpi_request->FunctionDependent1), 0, 0,
0, MPI2_SCSITASKMGMT_TASKTYPE_TARGET_RESET, 0, 30,
TM_MUTEX_ON);
0, MPI2_SCSITASKMGMT_TASKTYPE_TARGET_RESET, 0, 30);
} else
mpt3sas_base_hard_reset_handler(ioc, CAN_SLEEP,
FORCE_BIG_HAMMER);
Expand Down
66 changes: 31 additions & 35 deletions drivers/scsi/mpt3sas/mpt3sas_scsih.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2201,7 +2201,6 @@ mpt3sas_scsih_clear_tm_flag(struct MPT3SAS_ADAPTER *ioc, u16 handle)
* @type: MPI2_SCSITASKMGMT_TASKTYPE__XXX (defined in mpi2_init.h)
* @smid_task: smid assigned to the task
* @timeout: timeout in seconds
* @m_type: TM_MUTEX_ON or TM_MUTEX_OFF
* Context: user
*
* A generic API for sending task management requests to firmware.
Expand All @@ -2212,8 +2211,7 @@ mpt3sas_scsih_clear_tm_flag(struct MPT3SAS_ADAPTER *ioc, u16 handle)
*/
int
mpt3sas_scsih_issue_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle, uint channel,
uint id, uint lun, u8 type, u16 smid_task, ulong timeout,
enum mutex_type m_type)
uint id, uint lun, u8 type, u16 smid_task, ulong timeout)
{
Mpi2SCSITaskManagementRequest_t *mpi_request;
Mpi2SCSITaskManagementReply_t *mpi_reply;
Expand All @@ -2224,21 +2222,19 @@ mpt3sas_scsih_issue_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle, uint channel,
int rc;
u16 msix_task = 0;

if (m_type == TM_MUTEX_ON)
mutex_lock(&ioc->tm_cmds.mutex);
lockdep_assert_held(&ioc->tm_cmds.mutex);

if (ioc->tm_cmds.status != MPT3_CMD_NOT_USED) {
pr_info(MPT3SAS_FMT "%s: tm_cmd busy!!!\n",
__func__, ioc->name);
rc = FAILED;
goto err_out;
return FAILED;
}

if (ioc->shost_recovery || ioc->remove_host ||
ioc->pci_error_recovery) {
pr_info(MPT3SAS_FMT "%s: host reset in progress!\n",
__func__, ioc->name);
rc = FAILED;
goto err_out;
return FAILED;
}

ioc_state = mpt3sas_base_get_iocstate(ioc, 0);
Expand All @@ -2247,25 +2243,22 @@ mpt3sas_scsih_issue_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle, uint channel,
"unexpected doorbell active!\n", ioc->name));
rc = mpt3sas_base_hard_reset_handler(ioc, CAN_SLEEP,
FORCE_BIG_HAMMER);
rc = (!rc) ? SUCCESS : FAILED;
goto err_out;
return (!rc) ? SUCCESS : FAILED;
}

if ((ioc_state & MPI2_IOC_STATE_MASK) == MPI2_IOC_STATE_FAULT) {
mpt3sas_base_fault_info(ioc, ioc_state &
MPI2_DOORBELL_DATA_MASK);
rc = mpt3sas_base_hard_reset_handler(ioc, CAN_SLEEP,
FORCE_BIG_HAMMER);
rc = (!rc) ? SUCCESS : FAILED;
goto err_out;
return (!rc) ? SUCCESS : FAILED;
}

smid = mpt3sas_base_get_smid_hpr(ioc, ioc->tm_cb_idx);
if (!smid) {
pr_err(MPT3SAS_FMT "%s: failed obtaining a smid\n",
ioc->name, __func__);
rc = FAILED;
goto err_out;
return FAILED;
}

if (type == MPI2_SCSITASKMGMT_TASKTYPE_ABORT_TASK)
Expand Down Expand Up @@ -2302,9 +2295,7 @@ mpt3sas_scsih_issue_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle, uint channel,
rc = mpt3sas_base_hard_reset_handler(ioc, CAN_SLEEP,
FORCE_BIG_HAMMER);
rc = (!rc) ? SUCCESS : FAILED;
ioc->tm_cmds.status = MPT3_CMD_NOT_USED;
mpt3sas_scsih_clear_tm_flag(ioc, handle);
goto err_out;
goto out;
}
}

Expand Down Expand Up @@ -2356,17 +2347,23 @@ mpt3sas_scsih_issue_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle, uint channel,
break;
}

out:
mpt3sas_scsih_clear_tm_flag(ioc, handle);
ioc->tm_cmds.status = MPT3_CMD_NOT_USED;
if (m_type == TM_MUTEX_ON)
mutex_unlock(&ioc->tm_cmds.mutex);

return rc;
}

err_out:
if (m_type == TM_MUTEX_ON)
mutex_unlock(&ioc->tm_cmds.mutex);
return rc;
int mpt3sas_scsih_issue_locked_tm(struct MPT3SAS_ADAPTER *ioc, u16 handle,
uint channel, uint id, uint lun, u8 type, u16 smid_task, ulong timeout)
{
int ret;

mutex_lock(&ioc->tm_cmds.mutex);
ret = mpt3sas_scsih_issue_tm(ioc, handle, channel, id, lun, type,
smid_task, timeout);
mutex_unlock(&ioc->tm_cmds.mutex);

return ret;
}

/**
Expand Down Expand Up @@ -2482,9 +2479,9 @@ scsih_abort(struct scsi_cmnd *scmd)
mpt3sas_halt_firmware(ioc);

handle = sas_device_priv_data->sas_target->handle;
r = mpt3sas_scsih_issue_tm(ioc, handle, scmd->device->channel,
r = mpt3sas_scsih_issue_locked_tm(ioc, handle, scmd->device->channel,
scmd->device->id, scmd->device->lun,
MPI2_SCSITASKMGMT_TASKTYPE_ABORT_TASK, smid, 30, TM_MUTEX_ON);
MPI2_SCSITASKMGMT_TASKTYPE_ABORT_TASK, smid, 30);

out:
sdev_printk(KERN_INFO, scmd->device, "task abort: %s scmd(%p)\n",
Expand Down Expand Up @@ -2541,9 +2538,9 @@ scsih_dev_reset(struct scsi_cmnd *scmd)
goto out;
}

r = mpt3sas_scsih_issue_tm(ioc, handle, scmd->device->channel,
r = mpt3sas_scsih_issue_locked_tm(ioc, handle, scmd->device->channel,
scmd->device->id, scmd->device->lun,
MPI2_SCSITASKMGMT_TASKTYPE_LOGICAL_UNIT_RESET, 0, 30, TM_MUTEX_ON);
MPI2_SCSITASKMGMT_TASKTYPE_LOGICAL_UNIT_RESET, 0, 30);

out:
sdev_printk(KERN_INFO, scmd->device, "device reset: %s scmd(%p)\n",
Expand Down Expand Up @@ -2603,9 +2600,9 @@ scsih_target_reset(struct scsi_cmnd *scmd)
goto out;
}

r = mpt3sas_scsih_issue_tm(ioc, handle, scmd->device->channel,
r = mpt3sas_scsih_issue_locked_tm(ioc, handle, scmd->device->channel,
scmd->device->id, 0, MPI2_SCSITASKMGMT_TASKTYPE_TARGET_RESET, 0,
30, TM_MUTEX_ON);
30);

out:
starget_printk(KERN_INFO, starget, "target reset: %s scmd(%p)\n",
Expand Down Expand Up @@ -6089,8 +6086,7 @@ _scsih_sas_broadcast_primitive_event(struct MPT3SAS_ADAPTER *ioc,

spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags);
r = mpt3sas_scsih_issue_tm(ioc, handle, 0, 0, lun,
MPI2_SCSITASKMGMT_TASKTYPE_QUERY_TASK, smid, 30,
TM_MUTEX_OFF);
MPI2_SCSITASKMGMT_TASKTYPE_QUERY_TASK, smid, 30);
if (r == FAILED) {
sdev_printk(KERN_WARNING, sdev,
"mpt3sas_scsih_issue_tm: FAILED when sending "
Expand Down Expand Up @@ -6130,8 +6126,8 @@ _scsih_sas_broadcast_primitive_event(struct MPT3SAS_ADAPTER *ioc,
goto out_no_lock;

r = mpt3sas_scsih_issue_tm(ioc, handle, sdev->channel, sdev->id,
sdev->lun, MPI2_SCSITASKMGMT_TASKTYPE_ABORT_TASK, smid, 30,
TM_MUTEX_OFF);
sdev->lun, MPI2_SCSITASKMGMT_TASKTYPE_ABORT_TASK, smid,
30);
if (r == FAILED) {
sdev_printk(KERN_WARNING, sdev,
"mpt3sas_scsih_issue_tm: ABORT_TASK: FAILED : "
Expand Down

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