bnxt_en: Fix possible corrupted NVRAM parameters from firmware response.

In bnxt_find_nvram_item(), it is copying firmware response data after
releasing the mutex.  This can cause the firmware response data
to be corrupted if the next firmware response overwrites the response
buffer.  The rare problem shows up when running ethtool -i repeatedly.

Fix it by calling the new variant _hwrm_send_message_silent() that requires
the caller to take the mutex and to release it after the response data has
been copied.

Fixes: 3ebf6f0a ("bnxt_en: Add installed-package version reporting via Ethtool GDRVINFO")
Reported-by: Sarveswara Rao Mygapula <sarveswararao.mygapula@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -3466,6 +3466,12 @@ int _hwrm_send_message(struct bnxt *bp, void *msg, u32 msg_len, int timeout)
 	return bnxt_hwrm_do_send_msg(bp, msg, msg_len, timeout, false);
 }
 
+int _hwrm_send_message_silent(struct bnxt *bp, void *msg, u32 msg_len,
+			      int timeout)
+{
+	return bnxt_hwrm_do_send_msg(bp, msg, msg_len, timeout, true);
+}
+
 int hwrm_send_message(struct bnxt *bp, void *msg, u32 msg_len, int timeout)
 {
 	int rc;

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -1362,6 +1362,7 @@ void bnxt_set_ring_params(struct bnxt *);
 int bnxt_set_rx_skb_mode(struct bnxt *bp, bool page_mode);
 void bnxt_hwrm_cmd_hdr_init(struct bnxt *, void *, u16, u16, u16);
 int _hwrm_send_message(struct bnxt *, void *, u32, int);
+int _hwrm_send_message_silent(struct bnxt *bp, void *msg, u32 len, int timeout);
 int hwrm_send_message(struct bnxt *, void *, u32, int);
 int hwrm_send_message_silent(struct bnxt *, void *, u32, int);
 int bnxt_hwrm_func_rgtr_async_events(struct bnxt *bp, unsigned long *bmap,

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

@@ -1809,7 +1809,8 @@ static int bnxt_find_nvram_item(struct net_device *dev, u16 type, u16 ordinal,
 	req.dir_ordinal = cpu_to_le16(ordinal);
 	req.dir_ext = cpu_to_le16(ext);
 	req.opt_ordinal = NVM_FIND_DIR_ENTRY_REQ_OPT_ORDINAL_EQ;
-	rc = hwrm_send_message_silent(bp, &req, sizeof(req), HWRM_CMD_TIMEOUT);
+	mutex_lock(&bp->hwrm_cmd_lock);
+	rc = _hwrm_send_message_silent(bp, &req, sizeof(req), HWRM_CMD_TIMEOUT);
 	if (rc == 0) {
 		if (index)
 			*index = le16_to_cpu(output->dir_idx);
@@ -1818,6 +1819,7 @@ static int bnxt_find_nvram_item(struct net_device *dev, u16 type, u16 ordinal,
 		if (data_length)
 			*data_length = le32_to_cpu(output->dir_data_length);
 	}
+	mutex_unlock(&bp->hwrm_cmd_lock);
 	return rc;
 }