net: hns3: tracing: fix hclgevf trace event strings

The __string() and __assign_str() helper macros of the TRACE_EVENT() macro
are going through some optimizations where only the source string of
__string() will be used and the __assign_str() source will be ignored and
later removed.

To make sure that there's no issues, a new check is added between the
__string() src argument and the __assign_str() src argument that does a
strcmp() to make sure they are the same string.

The hclgevf trace events have:

__assign_str(devname, &hdev->nic.kinfo.netdev->name);

Which triggers the warning:

hclgevf_trace.h:34:39: error: passing argument 1 of ‘strcmp’ from incompatible pointer type [-Werror=incompatible-pointer-types]
34 | __assign_str(devname, &hdev->nic.kinfo.netdev->name);
[..]
arch/x86/include/asm/string_64.h:75:24: note: expected ‘const char *’ but argument is of type ‘char (*)[16]’
75 | int strcmp(const char *cs, const char *ct);
| ~~~~~~~~~~~~^~

Because __assign_str() now has:

WARN_ON_ONCE(__builtin_constant_p(src) ? \
strcmp((src), __data_offsets.dst##_ptr_) : \
(src) != __data_offsets.dst##_ptr_); \

The problem is the '&' on hdev->nic.kinfo.netdev->name. That's because
that name is:

char name[IFNAMSIZ]

Where passing an address '&' of a char array is not compatible with strcmp().

The '&' is not necessary, remove it.

Link: https://lore.kernel.org/linux-trace-kernel/[e-mail]

Cc: netdev <[e-mail]>
Cc: Yisen Zhuang <[e-mail]>
Cc: Salil Mehta <[e-mail]>
Cc: "David S. Miller" <[e-mail]>
Cc: Eric Dumazet <[e-mail]>
Cc: Jakub Kicinski <[e-mail]>
Cc: Yufeng Mo <[e-mail]>
Cc: Huazhong Tan <[e-mail]>
Cc: [e-mail]
Acked-by: Paolo Abeni <[e-mail]>
Reviewed-by: Jijie Shao <[e-mail]>
Fixes: d8355240cf8fb ("net: hns3: add trace event support for PF/VF mailbox")
Signed-off-by: Steven Rostedt (Google) <[e-mail]>

drivers/net/ethernet/hisilicon/hns3/hns3pf/hclge_trace.h

···
 		__field(u8, code)
 		__field(u8, subcode)
 		__string(pciname, pci_name(hdev->pdev))
-		__string(devname, &hdev->vport[0].nic.kinfo.netdev->name)
+		__string(devname, hdev->vport[0].nic.kinfo.netdev->name)
 		__array(u32, mbx_data, PF_GET_MBX_LEN)
 	),
 
···
 		__entry->code = req->msg.code;
 		__entry->subcode = req->msg.subcode;
 		__assign_str(pciname, pci_name(hdev->pdev));
-		__assign_str(devname, &hdev->vport[0].nic.kinfo.netdev->name);
+		__assign_str(devname, hdev->vport[0].nic.kinfo.netdev->name);
 		memcpy(__entry->mbx_data, req,
 		       sizeof(struct hclge_mbx_vf_to_pf_cmd));
 	),
···
 		__field(u8, vfid)
 		__field(u16, code)
 		__string(pciname, pci_name(hdev->pdev))
-		__string(devname, &hdev->vport[0].nic.kinfo.netdev->name)
+		__string(devname, hdev->vport[0].nic.kinfo.netdev->name)
 		__array(u32, mbx_data, PF_SEND_MBX_LEN)
 	),
 
···
 		__entry->vfid = req->dest_vfid;
 		__entry->code = le16_to_cpu(req->msg.code);
 		__assign_str(pciname, pci_name(hdev->pdev));
-		__assign_str(devname, &hdev->vport[0].nic.kinfo.netdev->name);
+		__assign_str(devname, hdev->vport[0].nic.kinfo.netdev->name);
 		memcpy(__entry->mbx_data, req,
 		       sizeof(struct hclge_mbx_pf_to_vf_cmd));
 	),

drivers/net/ethernet/hisilicon/hns3/hns3vf/hclgevf_trace.h

···
 		__field(u8, vfid)
 		__field(u16, code)
 		__string(pciname, pci_name(hdev->pdev))
-		__string(devname, &hdev->nic.kinfo.netdev->name)
+		__string(devname, hdev->nic.kinfo.netdev->name)
 		__array(u32, mbx_data, VF_GET_MBX_LEN)
 	),
 
···
 		__entry->vfid = req->dest_vfid;
 		__entry->code = le16_to_cpu(req->msg.code);
 		__assign_str(pciname, pci_name(hdev->pdev));
-		__assign_str(devname, &hdev->nic.kinfo.netdev->name);
+		__assign_str(devname, hdev->nic.kinfo.netdev->name);
 		memcpy(__entry->mbx_data, req,
 		       sizeof(struct hclge_mbx_pf_to_vf_cmd));
 	),
···
 		__field(u8, code)
 		__field(u8, subcode)
 		__string(pciname, pci_name(hdev->pdev))
-		__string(devname, &hdev->nic.kinfo.netdev->name)
+		__string(devname, hdev->nic.kinfo.netdev->name)
 		__array(u32, mbx_data, VF_SEND_MBX_LEN)
 	),
 
···
 		__entry->code = req->msg.code;
 		__entry->subcode = req->msg.subcode;
 		__assign_str(pciname, pci_name(hdev->pdev));
-		__assign_str(devname, &hdev->nic.kinfo.netdev->name);
+		__assign_str(devname, hdev->nic.kinfo.netdev->name);
 		memcpy(__entry->mbx_data, req,
 		       sizeof(struct hclge_mbx_vf_to_pf_cmd));
 	),