On Fri, Apr 07, 2017 at 07:59:08PM +0000, Bart Van Assche wrote:
> On Wed, 2017-04-05 at 07:41 -0400, Martin K. Petersen wrote:
> > +static ssize_t
> > +zeroing_mode_store(struct device *dev, struct device_attribute *attr,
> > + const char *buf, size_t count)
> > +{
> > + struct scsi_disk *sdkp = to_scsi_disk(dev);
> > +
> > + if (!capable(CAP_SYS_ADMIN))
> > + return -EACCES;
> > +
> > + if (!strncmp(buf, zeroing_mode[SD_ZERO_WRITE], 20))
> > + sdkp->zeroing_mode = SD_ZERO_WRITE;
> > + else if (!strncmp(buf, zeroing_mode[SD_ZERO_WS], 20))
> > + sdkp->zeroing_mode = SD_ZERO_WS;
> > + else if (!strncmp(buf, zeroing_mode[SD_ZERO_WS16_UNMAP], 20))
> > + sdkp->zeroing_mode = SD_ZERO_WS16_UNMAP;
> > + else if (!strncmp(buf, zeroing_mode[SD_ZERO_WS10_UNMAP], 20))
> > + sdkp->zeroing_mode = SD_ZERO_WS10_UNMAP;
> > + else
> > + return -EINVAL;
> > +
> > + return count;
> > +}
>
> An additional question about this function: if the shell command "echo" is
> used
> without command-line option -n to modify the "zeroing_mode" sysfs attribute
> then
> a newline character will be present in buf. Does the above code handle newline
> characters correctly?
It ignores the newlines. But we have a helper called sysfs_streq
to possible ignore it. It might be a good idea to move the various
sysfs files in scsi to use it.
