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be2iscsi: Fix soft lockup in mgmt_get_all_if_id path using bmbx 

We are taking mbox_lock spinlock which disables pre-emption before we
poll for mbox completion. Waiting there with spinlock held in excess of
20s will cause soft lockup.

Actual fix is to change mbox_lock to mutex. The changes are done in
phases. This is the first part.

1. Changed mgmt_get_all_if_id to use MCC where after posting lock is
released.

2. Changed be_mbox_db_ready_wait to busy wait for 12s max and removed
wait_event_timeout. Added error handling code for IO reads.
OPCODE_COMMON_QUERY_FIRMWARE_CONFIG mbox command takes 8s time when
unreachable boot targets configured.

Signed-off-by: Jitendra Bhivare <jitendra.bhivare@avagotech.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Jitendra Bhivare 2016-01-20 14:10:45 +05:30 committed by Martin K. Petersen
parent 420eb6d7ef
commit 6ac999efee
2 changed files with 52 additions and 42 deletions
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62
drivers/scsi/be2iscsi/be_cmds.c
View File

@ -587,47 +587,42 @@ int be_mcc_notify_wait(struct beiscsi_hba *phba)
**/
static int be_mbox_db_ready_wait(struct be_ctrl_info *ctrl)
{
#define BEISCSI_MBX_RDY_BIT_TIMEOUT 4000 /* 4sec */
#define BEISCSI_MBX_RDY_BIT_TIMEOUT 12000 /* 12sec */
void __iomem *db = ctrl->db + MPU_MAILBOX_DB_OFFSET;
struct beiscsi_hba *phba = pci_get_drvdata(ctrl->pdev);
unsigned long timeout;
bool read_flag = false;
int ret = 0, i;
u32 ready;
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(rdybit_check_q);
if (beiscsi_error(phba))
return -EIO;
timeout = jiffies + (HZ * 110);
/*
* This BMBX busy wait path is used during init only.
* For the commands executed during init, 5s should suffice.
*/
timeout = jiffies + msecs_to_jiffies(BEISCSI_MBX_RDY_BIT_TIMEOUT);
do {
for (i = 0; i < BEISCSI_MBX_RDY_BIT_TIMEOUT; i++) {
ready = ioread32(db) & MPU_MAILBOX_DB_RDY_MASK;
if (ready) {
read_flag = true;
break;
}
mdelay(1);
}
if (beiscsi_error(phba))
return -EIO;
if (!read_flag) {
wait_event_timeout(rdybit_check_q,
(read_flag != true),
HZ * 5);
}
} while ((time_before(jiffies, timeout)) && !read_flag);
ready = ioread32(db);
if (ready == 0xffffffff)
return -EIO;
if (!read_flag) {
beiscsi_log(phba, KERN_ERR,
BEISCSI_LOG_CONFIG | BEISCSI_LOG_MBOX,
"BC_%d : FW Timed Out\n");
phba->fw_timeout = true;
beiscsi_ue_detect(phba);
ret = -EBUSY;
}
ready &= MPU_MAILBOX_DB_RDY_MASK;
if (ready)
return 0;
return ret;
if (time_after(jiffies, timeout))
break;
mdelay(1);
} while (!ready);
beiscsi_log(phba, KERN_ERR,
BEISCSI_LOG_CONFIG | BEISCSI_LOG_MBOX,
"BC_%d : FW Timed Out\n");
phba->fw_timeout = true;
beiscsi_ue_detect(phba);
return -EBUSY;
}
/*
@ -674,6 +669,9 @@ int be_mbox_notify(struct be_ctrl_info *ctrl)
if (status)
return status;
/* RDY is set; small delay before CQE read. */
udelay(1);
if (be_mcc_compl_is_new(compl)) {
status = be_mcc_compl_process(ctrl, &mbox->compl);
be_mcc_compl_use(compl);

32
drivers/scsi/be2iscsi/be_mgmt.c
View File

@ -809,27 +809,39 @@ int mgmt_open_connection(struct beiscsi_hba *phba,
unsigned int mgmt_get_all_if_id(struct beiscsi_hba *phba)
{
struct be_ctrl_info *ctrl = &phba->ctrl;
struct be_mcc_wrb *wrb = wrb_from_mbox(&ctrl->mbox_mem);
struct be_cmd_get_all_if_id_req *req = embedded_payload(wrb);
struct be_cmd_get_all_if_id_req *pbe_allid = req;
struct be_mcc_wrb *wrb;
struct be_cmd_get_all_if_id_req *req;
struct be_cmd_get_all_if_id_req *pbe_allid;
unsigned int tag;
int status = 0;
memset(wrb, 0, sizeof(*wrb));
spin_lock(&ctrl->mbox_lock);
tag = alloc_mcc_tag(phba);
if (!tag) {
spin_unlock(&ctrl->mbox_lock);
return -ENOMEM;
}
wrb = wrb_from_mccq(phba);
req = embedded_payload(wrb);
wrb->tag0 |= tag;
be_wrb_hdr_prepare(wrb, sizeof(*req), true, 0);
be_cmd_hdr_prepare(&req->hdr, CMD_SUBSYSTEM_ISCSI,
OPCODE_COMMON_ISCSI_NTWK_GET_ALL_IF_ID,
sizeof(*req));
status = be_mbox_notify(ctrl);
if (!status)
phba->interface_handle = pbe_allid->if_hndl_list[0];
else {
be_mcc_notify(phba);
spin_unlock(&ctrl->mbox_lock);
status = beiscsi_mccq_compl(phba, tag, &wrb, NULL);
if (status) {
beiscsi_log(phba, KERN_WARNING, BEISCSI_LOG_CONFIG,
"BG_%d : Failed in mgmt_get_all_if_id\n");
return -EBUSY;
}
spin_unlock(&ctrl->mbox_lock);
pbe_allid = embedded_payload(wrb);
phba->interface_handle = pbe_allid->if_hndl_list[0];
return status;
}