4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tomer Tayar <tomer.ta...@cavium.com>

[ Upstream commit eaa50fc59e5841910987e90b0438b2643041f508 ]

The MFW manages an internal lock to prevent concurrent hardware
(de)initialization of different PFs.
This, together with the busy-waiting for the MFW's responses for commands,
might lead to a deadlock during concurrent load or unload of PFs.
This patch adds the option to sleep within the busy-waiting, and uses it
for the (un)load requests (which are not sent from an interrupt context) to
prevent the possible deadlock.

Signed-off-by: Tomer Tayar <tomer.ta...@cavium.com>
Signed-off-by: Ariel Elior <ariel.el...@cavium.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Sasha Levin <alexander.le...@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/net/ethernet/qlogic/qed/qed_mcp.c |   43 +++++++++++++++++++++---------
 drivers/net/ethernet/qlogic/qed/qed_mcp.h |   21 +++++++++-----
 2 files changed, 44 insertions(+), 20 deletions(-)

--- a/drivers/net/ethernet/qlogic/qed/qed_mcp.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
@@ -47,7 +47,7 @@
 #include "qed_reg_addr.h"
 #include "qed_sriov.h"
 
-#define CHIP_MCP_RESP_ITER_US 10
+#define QED_MCP_RESP_ITER_US   10
 
 #define QED_DRV_MB_MAX_RETRIES (500 * 1000)    /* Account for 5 sec */
 #define QED_MCP_RESET_RETRIES  (50 * 1000)     /* Account for 500 msec */
@@ -316,7 +316,7 @@ static void qed_mcp_reread_offsets(struc
 
 int qed_mcp_reset(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt)
 {
-       u32 org_mcp_reset_seq, seq, delay = CHIP_MCP_RESP_ITER_US, cnt = 0;
+       u32 org_mcp_reset_seq, seq, delay = QED_MCP_RESP_ITER_US, cnt = 0;
        int rc = 0;
 
        /* Ensure that only a single thread is accessing the mailbox */
@@ -448,10 +448,10 @@ static int
 _qed_mcp_cmd_and_union(struct qed_hwfn *p_hwfn,
                       struct qed_ptt *p_ptt,
                       struct qed_mcp_mb_params *p_mb_params,
-                      u32 max_retries, u32 delay)
+                      u32 max_retries, u32 usecs)
 {
+       u32 cnt = 0, msecs = DIV_ROUND_UP(usecs, 1000);
        struct qed_mcp_cmd_elem *p_cmd_elem;
-       u32 cnt = 0;
        u16 seq_num;
        int rc = 0;
 
@@ -474,7 +474,11 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *
                        goto err;
 
                spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);
-               udelay(delay);
+
+               if (QED_MB_FLAGS_IS_SET(p_mb_params, CAN_SLEEP))
+                       msleep(msecs);
+               else
+                       udelay(usecs);
        } while (++cnt < max_retries);
 
        if (cnt >= max_retries) {
@@ -503,7 +507,11 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *
                 * The spinlock stays locked until the list element is removed.
                 */
 
-               udelay(delay);
+               if (QED_MB_FLAGS_IS_SET(p_mb_params, CAN_SLEEP))
+                       msleep(msecs);
+               else
+                       udelay(usecs);
+
                spin_lock_bh(&p_hwfn->mcp_info->cmd_lock);
 
                if (p_cmd_elem->b_is_completed)
@@ -538,7 +546,7 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *
                   "MFW mailbox: response 0x%08x param 0x%08x [after %d.%03d 
ms]\n",
                   p_mb_params->mcp_resp,
                   p_mb_params->mcp_param,
-                  (cnt * delay) / 1000, (cnt * delay) % 1000);
+                  (cnt * usecs) / 1000, (cnt * usecs) % 1000);
 
        /* Clear the sequence number from the MFW response */
        p_mb_params->mcp_resp &= FW_MSG_CODE_MASK;
@@ -556,7 +564,7 @@ static int qed_mcp_cmd_and_union(struct
 {
        size_t union_data_size = sizeof(union drv_union_data);
        u32 max_retries = QED_DRV_MB_MAX_RETRIES;
-       u32 delay = CHIP_MCP_RESP_ITER_US;
+       u32 usecs = QED_MCP_RESP_ITER_US;
 
        /* MCP not initialized */
        if (!qed_mcp_is_init(p_hwfn)) {
@@ -573,8 +581,13 @@ static int qed_mcp_cmd_and_union(struct
                return -EINVAL;
        }
 
+       if (QED_MB_FLAGS_IS_SET(p_mb_params, CAN_SLEEP)) {
+               max_retries = DIV_ROUND_UP(max_retries, 1000);
+               usecs *= 1000;
+       }
+
        return _qed_mcp_cmd_and_union(p_hwfn, p_ptt, p_mb_params, max_retries,
-                                     delay);
+                                     usecs);
 }
 
 int qed_mcp_cmd(struct qed_hwfn *p_hwfn,
@@ -763,6 +776,7 @@ __qed_mcp_load_req(struct qed_hwfn *p_hw
        mb_params.data_src_size = sizeof(load_req);
        mb_params.p_data_dst = &load_rsp;
        mb_params.data_dst_size = sizeof(load_rsp);
+       mb_params.flags = QED_MB_FLAG_CAN_SLEEP;
 
        DP_VERBOSE(p_hwfn, QED_MSG_SP,
                   "Load Request: param 0x%08x [init_hw %d, drv_type %d, 
hsi_ver %d, pda 0x%04x]\n",
@@ -984,7 +998,8 @@ int qed_mcp_load_req(struct qed_hwfn *p_
 
 int qed_mcp_unload_req(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt)
 {
-       u32 wol_param, mcp_resp, mcp_param;
+       struct qed_mcp_mb_params mb_params;
+       u32 wol_param;
 
        switch (p_hwfn->cdev->wol_config) {
        case QED_OV_WOL_DISABLED:
@@ -1002,8 +1017,12 @@ int qed_mcp_unload_req(struct qed_hwfn *
                wol_param = DRV_MB_PARAM_UNLOAD_WOL_MCP;
        }
 
-       return qed_mcp_cmd(p_hwfn, p_ptt, DRV_MSG_CODE_UNLOAD_REQ, wol_param,
-                          &mcp_resp, &mcp_param);
+       memset(&mb_params, 0, sizeof(mb_params));
+       mb_params.cmd = DRV_MSG_CODE_UNLOAD_REQ;
+       mb_params.param = wol_param;
+       mb_params.flags = QED_MB_FLAG_CAN_SLEEP;
+
+       return qed_mcp_cmd_and_union(p_hwfn, p_ptt, &mb_params);
 }
 
 int qed_mcp_unload_done(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt)
--- a/drivers/net/ethernet/qlogic/qed/qed_mcp.h
+++ b/drivers/net/ethernet/qlogic/qed/qed_mcp.h
@@ -565,14 +565,19 @@ struct qed_mcp_info {
 };
 
 struct qed_mcp_mb_params {
-       u32                     cmd;
-       u32                     param;
-       void                    *p_data_src;
-       u8                      data_src_size;
-       void                    *p_data_dst;
-       u8                      data_dst_size;
-       u32                     mcp_resp;
-       u32                     mcp_param;
+       u32 cmd;
+       u32 param;
+       void *p_data_src;
+       void *p_data_dst;
+       u8 data_src_size;
+       u8 data_dst_size;
+       u32 mcp_resp;
+       u32 mcp_param;
+       u32 flags;
+#define QED_MB_FLAG_CAN_SLEEP  (0x1 << 0)
+#define QED_MB_FLAGS_IS_SET(params, flag) \
+       ({ typeof(params) __params = (params); \
+          (__params && (__params->flags & QED_MB_FLAG_ ## flag)); })
 };
 
 /**


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