Ira Weiny wrote: > The use of struct range in the CXL subsystem is growing. In particular, > the addition of Dynamic Capacity devices uses struct range in a number > of places which are reported in debug and error messages. > > To wit requiring the printing of the start/end fields in each print > became cumbersome. Dan Williams mentions in [1] that it might be time > to have a print specifier for struct range similar to struct resource > > A few alternatives were considered including '%par', '%r', and '%pn'. > %pra follows that struct range is similar to struct resource (%p[rR]) > but needs to be different. Based on discussions with Petr and Andy > '%pra' was chosen.[2] > > Andy also suggested to keep the range prints similar to struct resource > though combined code. Add hex_range() to handle printing for both > pointer types. > > Finally introduce DEFINE_RANGE() as a parallel to DEFINE_RES_*() and use > it in the tests. > > Cc: Jonathan Corbet <corbet@xxxxxxx> (maintainer:DOCUMENTATION) > Cc: linux-doc@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx (open list) > Link: https://lore.kernel.org/all/663922b475e50_d54d72945b@xxxxxxxxxxxxxxxxxxxxxxxxx.notmuch/ [1] > Link: https://lore.kernel.org/all/66cea3bf3332f_f937b29424@iweiny-mobl.notmuch/ [2] > Suggested-by: "Dan Williams" <dan.j.williams@xxxxxxxxx> > Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> > > --- > Changes: > [iweiny: split from CXL patch set] > [Andy: Define DEFINE_RANGE()] > [Andy: rework hex_range() logic] > [Andy: Don't use fallthrough] > [Andy: clean up help comment] > [Fan: clean up printk comment] > [Rasmus: fix buf processing in hex_range()] > [Rasmus: simplify buffer sizing] > [Rasmus: add '[' to string] > [Bagas: Clarify the start == end print behavior] > --- > Documentation/core-api/printk-formats.rst | 13 +++++++ > include/linux/range.h | 6 ++++ > lib/test_printf.c | 17 +++++++++ > lib/vsprintf.c | 57 +++++++++++++++++++++++++++---- > 4 files changed, 87 insertions(+), 6 deletions(-) > > diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst > index 14e093da3ccd..e1ebf0376154 100644 > --- a/Documentation/core-api/printk-formats.rst > +++ b/Documentation/core-api/printk-formats.rst > @@ -231,6 +231,19 @@ width of the CPU data path. > > Passed by reference. > > +Struct Range > +------------ > + > +:: > + > + %pra [range 0x0000000060000000-0x000000006fffffff] > + %pra [range 0x0000000060000000] > + > +For printing struct range. struct range holds an arbitrary range of u64 > +values. If start is equal to end only print the start value. I was going to say "why this special case that does not exist for the %pr case?", but then checked the code and found it *does* do this for %pr. So if you're going to document this special case for %pra might as well update the documentation for %pr too. Alternatively, drop the new %pra documentation for this corner case as accommodating the U64_MAX size range case is arguably a mistake in the caller. Either way, just make it consistent.
