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RDMA/bnxt_re: post destroy_ah for delayed completion of AH creation 

AH create may be called from interrpt context and driver has a special
timeout (8 sec) for this command. This is to avoid soft lockups when
the FW command takes more time. Driver returns -ETIMEOUT and fail
create AH, without waiting for actual completion from firmware.
When FW completion is received, use is_waiter_alive flag to avoid
a regular completion path.

If create_ah opcode is detected in completion path which does not have
waiter alive, driver will fetch ah_id from successful firmware
completion in the interrupt context and sends destroy_ah command
for same ah_id. This special post is done in quick manner using helper
function __send_message_no_waiter.

timeout_send is only used for debugging purposes.
If timeout_send value keeps incrementing, it indicates out of sync
active ah counter between driver and firmware. This is a limitation
but graceful handling is possible in future.

Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Link: https://lore.kernel.org/r/1686308514-11996-13-git-send-email-selvin.xavier@broadcom.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
This commit is contained in:
Kashyap Desai 2023-06-09 04:01:49 -07:00 committed by Leon Romanovsky
parent b6c7256688
commit 84911cf3b2
2 changed files with 110 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

108
drivers/infiniband/hw/bnxt_re/qplib_rcfw.c
View File

@ -175,6 +175,73 @@ static int __block_for_resp(struct bnxt_qplib_rcfw *rcfw, u16 cookie, u8 opcode)
return -ETIMEDOUT;
};
/* __send_message_no_waiter - get cookie and post the message.
* @rcfw - rcfw channel instance of rdev
* @msg - qplib message internal
*
* This function will just post and don't bother about completion.
* Current design of this function is -
* user must hold the completion queue hwq->lock.
* user must have used existing completion and free the resources.
* this function will not check queue full condition.
* this function will explicitly set is_waiter_alive=false.
* current use case is - send destroy_ah if create_ah is return
* after waiter of create_ah is lost. It can be extended for other
* use case as well.
*
* Returns: Nothing
*
*/
static void __send_message_no_waiter(struct bnxt_qplib_rcfw *rcfw,
struct bnxt_qplib_cmdqmsg *msg)
{
struct bnxt_qplib_cmdq_ctx *cmdq = &rcfw->cmdq;
struct bnxt_qplib_hwq *hwq = &cmdq->hwq;
struct bnxt_qplib_crsqe *crsqe;
struct bnxt_qplib_cmdqe *cmdqe;
u32 sw_prod, cmdq_prod;
u16 cookie, cbit;
u32 bsize;
u8 *preq;
cookie = cmdq->seq_num & RCFW_MAX_COOKIE_VALUE;
cbit = cookie % rcfw->cmdq_depth;
set_bit(cbit, cmdq->cmdq_bitmap);
__set_cmdq_base_cookie(msg->req, msg->req_sz, cpu_to_le16(cookie));
crsqe = &rcfw->crsqe_tbl[cbit];
/* Set cmd_size in terms of 16B slots in req. */
bsize = bnxt_qplib_set_cmd_slots(msg->req);
/* GET_CMD_SIZE would return number of slots in either case of tlv
* and non-tlv commands after call to bnxt_qplib_set_cmd_slots()
*/
crsqe->is_internal_cmd = true;
crsqe->is_waiter_alive = false;
crsqe->req_size = __get_cmdq_base_cmd_size(msg->req, msg->req_sz);
preq = (u8 *)msg->req;
do {
/* Locate the next cmdq slot */
sw_prod = HWQ_CMP(hwq->prod, hwq);
cmdqe = bnxt_qplib_get_qe(hwq, sw_prod, NULL);
/* Copy a segment of the req cmd to the cmdq */
memset(cmdqe, 0, sizeof(*cmdqe));
memcpy(cmdqe, preq, min_t(u32, bsize, sizeof(*cmdqe)));
preq += min_t(u32, bsize, sizeof(*cmdqe));
bsize -= min_t(u32, bsize, sizeof(*cmdqe));
hwq->prod++;
} while (bsize > 0);
cmdq->seq_num++;
cmdq_prod = hwq->prod;
atomic_inc(&rcfw->timeout_send);
/* ring CMDQ DB */
wmb();
writel(cmdq_prod, cmdq->cmdq_mbox.prod);
writel(RCFW_CMDQ_TRIG_VAL, cmdq->cmdq_mbox.db);
}
static int __send_message(struct bnxt_qplib_rcfw *rcfw,
struct bnxt_qplib_cmdqmsg *msg)
{
@ -219,6 +286,7 @@ static int __send_message(struct bnxt_qplib_rcfw *rcfw,
crsqe->free_slots = free_slots;
crsqe->resp = (struct creq_qp_event *)msg->resp;
crsqe->resp->cookie = cpu_to_le16(cookie);
crsqe->is_internal_cmd = false;
crsqe->is_waiter_alive = true;
crsqe->req_size = __get_cmdq_base_cmd_size(msg->req, msg->req_sz);
if (__get_cmdq_base_resp_size(msg->req, msg->req_sz) && msg->sb) {
@ -343,6 +411,26 @@ static int __send_message_basic_sanity(struct bnxt_qplib_rcfw *rcfw,
return 0;
}
/* This function will just post and do not bother about completion */
static void __destroy_timedout_ah(struct bnxt_qplib_rcfw *rcfw,
struct creq_create_ah_resp *create_ah_resp)
{
struct bnxt_qplib_cmdqmsg msg = {};
struct cmdq_destroy_ah req = {};
bnxt_qplib_rcfw_cmd_prep((struct cmdq_base *)&req,
CMDQ_BASE_OPCODE_DESTROY_AH,
sizeof(req));
req.ah_cid = create_ah_resp->xid;
msg.req = (struct cmdq_base *)&req;
msg.req_sz = sizeof(req);
__send_message_no_waiter(rcfw, &msg);
dev_info_ratelimited(&rcfw->pdev->dev,
"From %s: ah_cid = %d timeout_send %d\n",
__func__, req.ah_cid,
atomic_read(&rcfw->timeout_send));
}
/**
* __bnxt_qplib_rcfw_send_message - qplib interface to send
* and complete rcfw command.
@ -563,6 +651,8 @@ static int bnxt_qplib_process_qp_event(struct bnxt_qplib_rcfw *rcfw,
if (!test_and_clear_bit(cbit, rcfw->cmdq.cmdq_bitmap))
dev_warn(&pdev->dev,
"CMD bit %d was not requested\n", cbit);
if (crsqe->is_internal_cmd && !qp_event->status)
atomic_dec(&rcfw->timeout_send);
if (crsqe->is_waiter_alive) {
if (crsqe->resp)
@ -579,6 +669,24 @@ static int bnxt_qplib_process_qp_event(struct bnxt_qplib_rcfw *rcfw,
crsqe->resp = NULL;
hwq->cons += req_size;
/* This is a case to handle below scenario -
* Create AH is completed successfully by firmware,
* but completion took more time and driver already lost
* the context of create_ah from caller.
* We have already return failure for create_ah verbs,
* so let's destroy the same address vector since it is
* no more used in stack. We don't care about completion
* in __send_message_no_waiter.
* If destroy_ah is failued by firmware, there will be AH
* resource leak and relatively not critical + unlikely
* scenario. Current design is not to handle such case.
*/
if (!is_waiter_alive && !qp_event->status &&
qp_event->event == CREQ_QP_EVENT_EVENT_CREATE_AH)
__destroy_timedout_ah(rcfw,
(struct creq_create_ah_resp *)
qp_event);
spin_unlock_irqrestore(&hwq->lock, flags);
}
*num_wait += wait_cmds;

2
drivers/infiniband/hw/bnxt_re/qplib_rcfw.h
View File

@ -153,6 +153,7 @@ struct bnxt_qplib_crsqe {
/* Free slots at the time of submission */
u32 free_slots;
bool is_waiter_alive;
bool is_internal_cmd;
};
struct bnxt_qplib_rcfw_sbuf {
@ -225,6 +226,7 @@ struct bnxt_qplib_rcfw {
u32 cmdq_depth;
atomic_t rcfw_intr_enabled;
struct semaphore rcfw_inflight;
atomic_t timeout_send;
};
struct bnxt_qplib_cmdqmsg {