From: Kashyap Desai kashyap.desai@broadcom.com
[ Upstream commit 65288a22ddd81422a2a2a10c15df976a5332e41b ]
Whenever there is a fast path IO and create/destroy resources from the slow path is happening in parallel, we may notice high latency of slow path command completion.
Introduces a shadow queue depth to prevent the outstanding requests to the FW. Driver will not allow more than #RCFW_CMD_NON_BLOCKING_SHADOW_QD non-blocking commands to the Firmware.
Shadow queue depth is a soft limit only for non-blocking commands. Blocking commands will be posted to the firmware as long as there is a free slot.
Signed-off-by: Kashyap Desai kashyap.desai@broadcom.com Signed-off-by: Selvin Xavier selvin.xavier@broadcom.com Link: https://lore.kernel.org/r/1686308514-11996-8-git-send-email-selvin.xavier@br... Signed-off-by: Leon Romanovsky leon@kernel.org Stable-dep-of: 29900bf351e1 ("RDMA/bnxt_re: Fix hang during driver unload") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/hw/bnxt_re/qplib_rcfw.c | 60 +++++++++++++++++++++- drivers/infiniband/hw/bnxt_re/qplib_rcfw.h | 3 ++ 2 files changed, 61 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c index bfa0f29c7abf4..42484a1149c7c 100644 --- a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c +++ b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.c @@ -281,8 +281,21 @@ static int __send_message(struct bnxt_qplib_rcfw *rcfw, return 0; }
-int bnxt_qplib_rcfw_send_message(struct bnxt_qplib_rcfw *rcfw, - struct bnxt_qplib_cmdqmsg *msg) +/** + * __bnxt_qplib_rcfw_send_message - qplib interface to send + * and complete rcfw command. + * @rcfw - rcfw channel instance of rdev + * @msg - qplib message internal + * + * This function does not account shadow queue depth. It will send + * all the command unconditionally as long as send queue is not full. + * + * Returns: + * 0 if command completed by firmware. + * Non zero if the command is not completed by firmware. + */ +static int __bnxt_qplib_rcfw_send_message(struct bnxt_qplib_rcfw *rcfw, + struct bnxt_qplib_cmdqmsg *msg) { struct creq_qp_event *evnt = (struct creq_qp_event *)msg->resp; u16 cookie; @@ -331,6 +344,48 @@ int bnxt_qplib_rcfw_send_message(struct bnxt_qplib_rcfw *rcfw,
return rc; } + +/** + * bnxt_qplib_rcfw_send_message - qplib interface to send + * and complete rcfw command. + * @rcfw - rcfw channel instance of rdev + * @msg - qplib message internal + * + * Driver interact with Firmware through rcfw channel/slow path in two ways. + * a. Blocking rcfw command send. In this path, driver cannot hold + * the context for longer period since it is holding cpu until + * command is not completed. + * b. Non-blocking rcfw command send. In this path, driver can hold the + * context for longer period. There may be many pending command waiting + * for completion because of non-blocking nature. + * + * Driver will use shadow queue depth. Current queue depth of 8K + * (due to size of rcfw message there can be actual ~4K rcfw outstanding) + * is not optimal for rcfw command processing in firmware. + * + * Restrict at max #RCFW_CMD_NON_BLOCKING_SHADOW_QD Non-Blocking rcfw commands. + * Allow all blocking commands until there is no queue full. + * + * Returns: + * 0 if command completed by firmware. + * Non zero if the command is not completed by firmware. + */ +int bnxt_qplib_rcfw_send_message(struct bnxt_qplib_rcfw *rcfw, + struct bnxt_qplib_cmdqmsg *msg) +{ + int ret; + + if (!msg->block) { + down(&rcfw->rcfw_inflight); + ret = __bnxt_qplib_rcfw_send_message(rcfw, msg); + up(&rcfw->rcfw_inflight); + } else { + ret = __bnxt_qplib_rcfw_send_message(rcfw, msg); + } + + return ret; +} + /* Completions */ static int bnxt_qplib_process_func_event(struct bnxt_qplib_rcfw *rcfw, struct creq_func_event *func_event) @@ -937,6 +992,7 @@ int bnxt_qplib_enable_rcfw_channel(struct bnxt_qplib_rcfw *rcfw, return rc; }
+ sema_init(&rcfw->rcfw_inflight, RCFW_CMD_NON_BLOCKING_SHADOW_QD); bnxt_qplib_start_rcfw(rcfw);
return 0; diff --git a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.h b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.h index 92f7a25533d3b..675c388348827 100644 --- a/drivers/infiniband/hw/bnxt_re/qplib_rcfw.h +++ b/drivers/infiniband/hw/bnxt_re/qplib_rcfw.h @@ -67,6 +67,8 @@ static inline void bnxt_qplib_rcfw_cmd_prep(struct cmdq_base *req, req->cmd_size = cmd_size; }
+/* Shadow queue depth for non blocking command */ +#define RCFW_CMD_NON_BLOCKING_SHADOW_QD 64 #define RCFW_CMD_WAIT_TIME_MS 20000 /* 20 Seconds timeout */
/* CMDQ elements */ @@ -201,6 +203,7 @@ struct bnxt_qplib_rcfw { u64 oos_prev; u32 init_oos_stats; u32 cmdq_depth; + struct semaphore rcfw_inflight; };
struct bnxt_qplib_cmdqmsg {