Hi Huai-Yuan, Sorry for noticing this later, but a return len while len is 0 would result in a silent $(cat /sys/class/scsi_host/host*/lpfc_xcvr_data). Perhaps, it's better to log something to at least notify the user why SFP information was not able to be collected. How about something like this? /* Get transceiver information */ rdp_context = kmalloc(sizeof(*rdp_context), GFP_KERNEL); + if (!rdp_context) { + len = scnprintf(buf, PAGE_SIZE - len, + "SFP info NA: alloc failure\n"); + return len; + } rc = lpfc_get_sfp_info_wait(phba, rdp_context); if (rc) { Thanks, Justin Tee