On Mon, Nov 04, 2019 at 05:15:34PM +0200, Jani Nikula wrote: > On Mon, 04 Nov 2019, Amol Grover <frextrite@xxxxxxxxx> wrote: > > Convert RCU API method text to sub-headings and > > add hyperlink and superscript to 2 literary notes > > under rcu_dereference() section > > > > Signed-off-by: Amol Grover <frextrite@xxxxxxxxx> > > --- > > Documentation/RCU/whatisRCU.rst | 34 +++++++++++++++++++++++++++------ > > 1 file changed, 28 insertions(+), 6 deletions(-) > > > > diff --git a/Documentation/RCU/whatisRCU.rst b/Documentation/RCU/whatisRCU.rst > > index ae40c8bcc56c..3cf6e17d0065 100644 > > --- a/Documentation/RCU/whatisRCU.rst > > +++ b/Documentation/RCU/whatisRCU.rst > > @@ -150,6 +150,7 @@ later. See the kernel docbook documentation for more info, or look directly > > at the function header comments. > > > > rcu_read_lock() > > +^^^^^^^^^^^^^^^ > > > > void rcu_read_lock(void); > > > > @@ -164,6 +165,7 @@ rcu_read_lock() > > longer-term references to data structures. > > > > rcu_read_unlock() > > +^^^^^^^^^^^^^^^^^ > > > > void rcu_read_unlock(void); > > > > @@ -172,6 +174,7 @@ rcu_read_unlock() > > read-side critical sections may be nested and/or overlapping. > > > > synchronize_rcu() > > +^^^^^^^^^^^^^^^^^ > > > > void synchronize_rcu(void); > > > > @@ -225,6 +228,7 @@ synchronize_rcu() > > checklist.txt for some approaches to limiting the update rate. > > > > rcu_assign_pointer() > > +^^^^^^^^^^^^^^^^^^^^ > > > > void rcu_assign_pointer(p, typeof(p) v); > > > > @@ -245,6 +249,7 @@ rcu_assign_pointer() > > the _rcu list-manipulation primitives such as list_add_rcu(). > > > > rcu_dereference() > > +^^^^^^^^^^^^^^^^^ > > > > typeof(p) rcu_dereference(p); > > > > @@ -279,8 +284,10 @@ rcu_dereference() > > if an update happened while in the critical section, and incur > > unnecessary overhead on Alpha CPUs. > > > > +.. _back_to_1: > > + > > Note that the value returned by rcu_dereference() is valid > > - only within the enclosing RCU read-side critical section [1]. > > + only within the enclosing RCU read-side critical section |cs_1|. > > For example, the following is -not- legal:: > > > > rcu_read_lock(); > > @@ -298,15 +305,27 @@ rcu_dereference() > > it was acquired is just as illegal as doing so with normal > > locking. > > > > +.. _back_to_2: > > + > > As with rcu_assign_pointer(), an important function of > > rcu_dereference() is to document which pointers are protected by > > RCU, in particular, flagging a pointer that is subject to changing > > at any time, including immediately after the rcu_dereference(). > > And, again like rcu_assign_pointer(), rcu_dereference() is > > typically used indirectly, via the _rcu list-manipulation > > - primitives, such as list_for_each_entry_rcu() [2]. > > + primitives, such as list_for_each_entry_rcu() |entry_2|. > > + > > +.. |cs_1| raw:: html > > Please don't use raw. It's ugly and error prone. We have some raw output > for latex, but this would be the first for html. > > What are you trying to achieve? Hi Jani, While going through the documentation I encountered a few footnotes (numbers [1] and [2]) which referenced the actual footnote somewhere below the text. They were particularly not straight-forward to find hence I decided to link them to the footnote text which could be done using inline markup. Then I tried to make them more appealing by converting to super-scripts (the way they look like in books and websites). However, nested inline markup is not yet possible in reST hence I went with the html way to achieve the same. Too much? Thank you Amol > > BR, > Jani. > > > + > > + <a href="#cs"><sup>[1]</sup></a> > > + > > +.. |entry_2| raw:: html > > > > - [1] The variant rcu_dereference_protected() can be used outside > > + <a href="#entry"><sup>[2]</sup></a> > > + > > +.. _cs: > > + > > + \ :sup:`[1]`\ The variant rcu_dereference_protected() can be used outside > > of an RCU read-side critical section as long as the usage is > > protected by locks acquired by the update-side code. This variant > > avoids the lockdep warning that would happen when using (for > > @@ -317,15 +336,18 @@ rcu_dereference() > > a lockdep expression to indicate which locks must be acquired > > by the caller. If the indicated protection is not provided, > > a lockdep splat is emitted. See Documentation/RCU/Design/Requirements/Requirements.rst > > - and the API's code comments for more details and example usage. > > + and the API's code comments for more details and example usage. :ref:`back <back_to_1>` > > + > > + > > +.. _entry: > > > > - [2] If the list_for_each_entry_rcu() instance might be used by > > + \ :sup:`[2]`\ If the list_for_each_entry_rcu() instance might be used by > > update-side code as well as by RCU readers, then an additional > > lockdep expression can be added to its list of arguments. > > For example, given an additional "lock_is_held(&mylock)" argument, > > the RCU lockdep code would complain only if this instance was > > invoked outside of an RCU read-side critical section and without > > - the protection of mylock. > > + the protection of mylock. :ref:`back <back_to_2>` > > > > The following diagram shows how each API communicates among the > > reader, updater, and reclaimer. > > -- > Jani Nikula, Intel Open Source Graphics Center
