On Thu, 25 Jan 2018, Petr Mladek wrote: > From: Jason Baron <[email protected]> > > We are going to add a feature called atomic replace. It will allow to > create a patch that would replace all already registered patches. > For this, we will need to dynamically create funcs' and objects' > for functions that are not longer patched. > > This patch adds basic framework to handle such dynamic structures. > > It adds enum klp_func_type that allows to distinguish the dynamically > allocated funcs' structures. Note that objects' structures do not have > a clear type. Namely the static objects' structures might list both static > and dynamic funcs' structures. > > The function type is then used to limit klp_free() functions. We will > want to free the dynamic structures separately when they are not > longer needed. At the same time, we also want to make our life easier, > and introduce _any_ type that will allow to process all existing > structures in one go. > > We need to be careful here. First, objects' structures must be freed > only when all listed funcs' structures are freed. Also we must avoid > double free. Both problems are solved by removing the freed structures > from the list. > > Also note that klp_free*() functions are called also in klp_init_patch() > error path when only some kobjects have been initialized. The other > dynamic structures must be freed immediately by calling the respective > klp_free_*_dynamic() functions. > > Finally, the dynamic objects' structures are generic. The respective > klp_allocate_object_dynamic() and klp_free_object_dynamic() can > be implemented here. On the other hand, klp_free_func_dynamic() > is empty. It must be updated when a particular dynamic > klp_func_type is introduced. > > Signed-off-by: Jason Baron <[email protected]> > [[email protected]: Converted into a generic API] > Signed-off-by: Petr Mladek <[email protected]> > Cc: Josh Poimboeuf <[email protected]> > Cc: Jessica Yu <[email protected]> > Cc: Jiri Kosina <[email protected]> > Cc: Miroslav Benes <[email protected]> > --- > include/linux/livepatch.h | 37 +++++++++++- > kernel/livepatch/core.c | 139 > ++++++++++++++++++++++++++++++++++++++++------ > 2 files changed, 159 insertions(+), 17 deletions(-) > > diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h > index e5db2ba7e2a5..21cad200f949 100644 > --- a/include/linux/livepatch.h > +++ b/include/linux/livepatch.h > @@ -35,12 +35,22 @@ > #define KLP_UNPATCHED 0 > #define KLP_PATCHED 1 > > +/* > + * Function type is used to distinguish dynamically allocated structures > + * and limit some operations. > + */ > +enum klp_func_type { > + KLP_FUNC_ANY = -1, /* Substitute any type */ > + KLP_FUNC_ORIGINAL = 0, /* Original statically defined structure */
Wouldn't KLP_FUNC_STATIC be better? KLP_FUNC_ORIGINAL confused me couple of times. Miroslav
