Messages in this thread | | | Date | Thu, 2 Mar 2023 11:45:54 +0100 | Subject | Re: [PATCH v4 00/24] Remove COMMAND_LINE_SIZE from uapi | From | Alexandre Ghiti <> |
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On 3/2/23 11:44, Geert Uytterhoeven wrote: > Hi Alex, > > On Thu, Mar 2, 2023 at 11:09 AM Alexandre Ghiti <alex@ghiti.fr> wrote: >> On 3/2/23 10:47, Geert Uytterhoeven wrote: >>> On Thu, Mar 2, 2023 at 10:35 AM Alexandre Ghiti <alexghiti@rivosinc.com> wrote: >>>> This all came up in the context of increasing COMMAND_LINE_SIZE in the >>>> RISC-V port. In theory that's a UABI break, as COMMAND_LINE_SIZE is the >>>> maximum length of /proc/cmdline and userspace could staticly rely on >>>> that to be correct. >>>> >>>> Usually I wouldn't mess around with changing this sort of thing, but >>>> PowerPC increased it with a5980d064fe2 ("powerpc: Bump COMMAND_LINE_SIZE >>>> to 2048"). There are also a handful of examples of COMMAND_LINE_SIZE >>>> increasing, but they're from before the UAPI split so I'm not quite sure >>>> what that means: e5a6a1c90948 ("powerpc: derive COMMAND_LINE_SIZE from >>>> asm-generic"), 684d2fd48e71 ("[S390] kernel: Append scpdata to kernel >>>> boot command line"), 22242681cff5 ("MIPS: Extend COMMAND_LINE_SIZE"), >>>> and 2b74b85693c7 ("sh: Derive COMMAND_LINE_SIZE from >>>> asm-generic/setup.h."). >>>> >>>> It seems to me like COMMAND_LINE_SIZE really just shouldn't have been >>>> part of the uapi to begin with, and userspace should be able to handle >>>> /proc/cmdline of whatever length it turns out to be. I don't see any >>>> references to COMMAND_LINE_SIZE anywhere but Linux via a quick Google >>>> search, but that's not really enough to consider it unused on my end. >>>> >>>> This issue was already considered in s390 and they reached the same >>>> conclusion in commit 622021cd6c56 ("s390: make command line >>>> configurable"). >>>> >>>> The feedback on the v1 seemed to indicate that COMMAND_LINE_SIZE really >>>> shouldn't be part of uapi, so this now touches all the ports. I've >>>> tried to split this all out and leave it bisectable, but I haven't >>>> tested it all that aggressively. >>>> >>>> Changes since v3 <https://lore.kernel.org/all/20230214074925.228106-1-alexghiti@rivosinc.com/>: >>>> * Added RB/AB >>>> * Added a mention to commit 622021cd6c56 ("s390: make command line >>>> configurable") in the cover letter >>> Thanks for the update! >>> >>> Apparently you forgot to add your own SoB? >> I do not know, should I? Palmer did all the work, I only fixed 3 minor >> things > If you are picking up patches, and submitting them to someone else > for upstream inclusion, you should add your own SoB. > https://elixir.bootlin.com/linux/latest/source/Documentation/process/submitting-patches.rst#L419
Great, thanks for the pointer, I'll do that then!
Thanks again,
Alex
> Gr{oetje,eeting}s, > > Geert >
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