On Mon, Feb 11, 2013 at 5:25 PM, anish singh <anish198519851...@gmail.com>wrote:
> > > On Mon, Feb 11, 2013 at 4:51 PM, पारस <bepa...@gmail.com> wrote: > > Hi All, > > > > To read/write data to user-space from kernel-space we use > copy_from_user() > > and copy_to_user() functions. > > > > What is the use of these function? > > Why kernel can't directly access user address and read/write on to it? > what will happen if the user space process gets scheduled out while > you were using it? > > copy_to/from_user should always be called from process context. So even if a process is scheduled out there is not impact, as when process schedule back in copying will resume to/from correct page. > > Can any one explain why kernel can't directly access the user-space > address. > > > > Thanks > > > > > > _______________________________________________ > > Kernelnewbies mailing list > > Kernelnewbies@kernelnewbies.org > > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > > > > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@kernelnewbies.org > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > >
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
