linux: add CXL device serial number

Signed-off-by: Zubiao Xiong <zubiao.xiong@memverge.com>

Author: xiongzubiao

doc/hwloc.doxy

@@ -2109,13 +2109,16 @@ A Solaris-specific general processor type name, such as "i86pc".
 These info attributes are attached to OS device objects specified in parentheses.
 
 <dl>
-<dt>Vendor, Model, Revision, SerialNumber, Size, SectorSize (Storage OS devices)</dt>
-<dd>The vendor and model names, revision, serial number, size (in KiB = 1024 bytes)
+<dt>Vendor, Model, Revision, Size, SectorSize (Storage OS devices)</dt>
+<dd>The vendor and model names, revision, size (in KiB = 1024 bytes)
 and SectorSize (in bytes).
 </dd>
 <dt>LinuxDeviceID (Storage OS devices)</dt>
 <dd>The major/minor device number such as 8:0 of Linux device.
 </dd>
+<dt>SerialNumber (Storage and CXL Memory OS devices)</dt>
+<dd>The serial number of the device.
+</dd>
 <dt>CXLRAMSize, CXLPMEMSize (CXL Memory OS devices)</dt>
 <dd>The size of the volatile (RAM) or persistent (PMEM) memory
  in a CXL Type-3 device.

hwloc/topology-linux.c

@@ -6837,6 +6837,14 @@ hwloc_linuxfs_cxlmem_fillinfos(int root_fd,
       hwloc_obj_add_info(obj, "CXLPMEMSize", tmp);
     }
   }
+
+  snprintf(path, sizeof(path), "%s/serial", osdevpath);
+  if (hwloc_read_path_by_length(path, tmp, sizeof(tmp), root_fd) > 0) {
+    char *end = strchr(tmp, '\n');
+    if (end)
+      *end = '\0';
+    hwloc_obj_add_info(obj, "SerialNumber", tmp);
+  }
 }
 
 static int