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Commit eaa50fc5 authored by Tomer Tayar's avatar Tomer Tayar Committed by David S. Miller
Browse files

qed: Prevent a possible deadlock during driver load and unload 



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: default avatarTomer Tayar <Tomer.Tayar@cavium.com>
Signed-off-by: default avatarAriel Elior <Ariel.Elior@cavium.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 76271809

drivers/net/ethernet/qlogic/qed/qed_mcp.c

+31 −12
Original line number Diff line number Diff line
@@ -48,7 +48,7 @@ 
#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 */
@@ -317,7 +317,7 @@ static void qed_mcp_reread_offsets(struct qed_hwfn *p_hwfn, 


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 */
@@ -449,10 +449,10 @@ 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;
@@ -475,7 +475,11 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *p_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) {
@@ -504,7 +508,11 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *p_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)
@@ -539,7 +547,7 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *p_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;
@@ -557,7 +565,7 @@ static int qed_mcp_cmd_and_union(struct qed_hwfn *p_hwfn, 
{

	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)) {
@@ -574,8 +582,13 @@ static int qed_mcp_cmd_and_union(struct qed_hwfn *p_hwfn, 
		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,
@@ -793,6 +806,7 @@ __qed_mcp_load_req(struct qed_hwfn *p_hwfn, 
	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",
@@ -1014,7 +1028,8 @@ int qed_mcp_load_req(struct qed_hwfn *p_hwfn, 


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:
@@ -1032,8 +1047,12 @@ int qed_mcp_unload_req(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt) 
		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)

drivers/net/ethernet/qlogic/qed/qed_mcp.h

+13 −8
Original line number Diff line number Diff line
@@ -663,11 +663,16 @@ struct qed_mcp_mb_params { 
	u32 cmd;

	u32 param;

	void *p_data_src;

	u8			data_src_size;

	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)); })

};



struct qed_drv_tlv_hdr {