On Thu, Feb 11, 2021 at 10:08:38AM +0100, Gustavo Pimentel wrote: > +static ssize_t write_show(struct device *dev, struct device_attribute *attr, > + char *buf) > +{ > + struct pci_dev *pdev = to_pci_dev(dev); > + struct dw_xdata *dw = pci_get_drvdata(pdev); > + u64 rate; > + > + mutex_lock(&dw->mutex); > + dw_xdata_perf(dw, &rate, true); > + mutex_unlock(&dw->mutex); > + > + return sysfs_emit(buf, "%llu MB/s\n", rate); Do not put units in a sysfs file, that should be in the documentation, otherwise this forces userspace to "parse" the units which is a mess. Same for the other sysfs file. And why do you need a lock for this show function? thanks, greg k-h