Messages in this thread | | | Date | Mon, 18 Jan 2021 08:38:21 -0500 | From | Sasha Levin <> | Subject | Re: [PATCH] kbuild: give SUBLEVEL more room in KERNEL_VERSION |
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On Mon, Jan 18, 2021 at 10:21:16AM +0100, Greg KH wrote: >On Sun, Jan 17, 2021 at 08:49:51PM -0500, Sasha Levin wrote: >> SUBLEVEL only has 8 bits of space, which means that we'll overflow it >> once it reaches 256. >> >> Few of the stable branches will imminently overflow SUBLEVEL while >> there's no risk of overflowing VERSION. >> >> Thus, give SUBLEVEL 8 more bits which will be stolen from VERSION, this >> should create a better balance between the different version numbers we >> use. >> >> The downside here is that Linus will have 8 bits less to play with, but >> given our current release cadence (~10 weeks), the number of Linus's >> fingers & toes (20), and the current VERSION (5) we can calculate that >> VERSION will overflow in just over 1,000 years, so I'm kicking this can >> down the road. >> >> Cc: stable@kernel.org >> Signed-off-by: Sasha Levin <sashal@kernel.org> >> --- >> Makefile | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/Makefile b/Makefile >> index 9e73f82e0d863..dc2bad7a440d8 100644 >> --- a/Makefile >> +++ b/Makefile >> @@ -1252,8 +1252,8 @@ endef >> >> define filechk_version.h >> echo \#define LINUX_VERSION_CODE $(shell \ >> - expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 0$(SUBLEVEL)); \ >> - echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))' >> + expr $(VERSION) \* 16777216 + 0$(PATCHLEVEL) \* 65536 + 0$(SUBLEVEL)); \ >> + echo '#define KERNEL_VERSION(a,b,c) (((a) << 24) + ((b) << 16) + (c))' > >As much as I agree, this will break in-tree users of LINUX_VERSION_CODE >that try to suck out the version/patchlevel number of the kernel release >into their own fields. Things like USB host controller strings, v4l >ioctl reports, scsi driver ioctls, and other places do fun bit-movements >to try to unreverse this bit packing. > >So how about we just provide a "real" version/subversion/revision >#define as well, and clean up all in-kernel users, so we can get this to >work, and we can change it in the future more easily.
Uh, yes, I see what you mean. I'll fix those up and resend.
-- Thanks, Sasha
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