On Wed, Jan 27, 2021 at 9:10 AM Greg KH <greg@xxxxxxxxx> wrote: > > On Tue, Jan 26, 2021 at 11:07:24PM +0530, Mohana Datta Yelugoti wrote: > > Hello everyone, > > > > I am going through Documentation/filesystems/sysfs.rst. > > > > It says that sysfs allocates a buffer of size PAGE_SIZE and > > passes it to the show/store functions of the attribute. On > > read(), the show() method should fill the entire buffer[0]. > > No, that's not the case. Please only fill in what you need sent back to > userspace and return the number of bytes you used. A simple call to > sprintf() or better yet, sysfs_emit(), as a return statement is all you > need to do. > > See the thousands of examples in the kernel of this if you need proof :) > And Mohana, try it out and once you understand how the API really works, feel free to provide a patch to Documentation/filesystems/sysfs.rst to describe the actual behavior. Lukas _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
