Messages in this thread | | | From | Arnd Bergmann <> | Date | Mon, 17 May 2021 09:27:01 +0200 | Subject | Re: [PATCH 5/6] [v2] asm-generic: uaccess: remove inline strncpy_from_user/strnlen_user |
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On Mon, May 17, 2021 at 8:20 AM Christoph Hellwig <hch@lst.de> wrote: > > On Sat, May 15, 2021 at 12:18:02PM +0200, Arnd Bergmann wrote: > > From: Arnd Bergmann <arnd@arndb.de> > > > > Consolidate the asm-generic implementation with the library version > > that is used everywhere else. > > > > These are the three versions for NOMMU kernels, > > I don't get the three versions part?
Right, that was confusing. Rewording to
| The inline version is used on three NOMMU architectures and is | particularly inefficient when it scans the string one byte at a time | twice. It also lacks a check for user_addr_max(), but this is | probably ok on NOMMU targets. | | Consolidate the asm-generic implementation with the library version | that is used everywhere else. This version is generalized enough to | work efficiently on both MMU and NOMMU targets, and using the | same code everywhere reduces the potential for subtle bugs.
> > + select GENERIC_STRNCPY_FROM_USER > > + select GENERIC_STRNLEN_USER > > Given that most architetures select the generic version I wonder > if it might be worth to add another patch to invert the logic so > that architectures with their own implementation need to sekect a symbol.
Done now, using 'CONFIG_ARCH_HAS_{STRNCPY_FROM,STRNLEN}_USER'.
There are still seven or eight architectures that provide their own though.
> > +extern long strncpy_from_user(char *dst, const char __user *src, long count); > > +extern long strnlen_user(const char __user *src, long n); > > No need for the extern here.
Removed.
Arnd
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