On Mon, Dec 09, 2002 at 10:48:07AM +0100, M. Gerards wrote: > Hi, > > Can someone please explain me what diskfs_catch_exception is used for and why? > What is the difference between the diskpager and the file pagers? iow. why is > diskfs_catch_exceptions used for diskpagers and not for filepagers?
If you access a mapped page, you always risk to segfault if there is a trouble with the pager or if you calculated the page incorrectly. Because we don't want to crash in this particular case, we set up a signal preemptor. The catch exception macros can be used to switch on/off protected access to the disk image. File system pagers are never mapped into the filesystem address space. The filesystem pagers exist solely for user mappings, and for read/write operations via pager_memcpy (see libdiskfs/rdwr-internal.c). As there is no mapping, there is no need to protect against signals when accessing them. Thanks, Marcus -- `Rhubarb is no Egyptian god.' GNU http://www.gnu.org [EMAIL PROTECTED] Marcus Brinkmann The Hurd http://www.gnu.org/software/hurd/ [EMAIL PROTECTED] http://www.marcus-brinkmann.de/ _______________________________________________ Help-hurd mailing list [EMAIL PROTECTED] http://mail.gnu.org/mailman/listinfo/help-hurd
