On Tue, Jun 13, 2017 at 02:04:11PM +0300, Yury Norov wrote: > On Thu, Jun 08, 2017 at 04:09:50PM +0100, Catalin Marinas wrote: > > On Sun, Jun 04, 2017 at 02:59:51PM +0300, Yury Norov wrote: > > > All new 32-bit architectures should have 64-bit off_t type, but existing > > > architectures has 32-bit ones. > > > > > > To handle it, new config option is added to arch/Kconfig that defaults > > > ARCH_32BIT_OFF_T to be disabled for non-64 bit architectures. All existing > > > 32-bit architectures enable it explicitly here. > > > > > > New option affects force_o_largefile() behaviour. Namely, if off_t is > > > 64-bits long, we have no reason to reject user to open big files. > > > > > > Note that even if architectures has only 64-bit off_t in the kernel > > > (arc, c6x, h8300, hexagon, metag, nios2, openrisc, tile32 and unicore32), > > > a libc may use 32-bit off_t, and therefore want to limit the file size > > > to 4GB unless specified differently in the open flags. > > > > > > Signed-off-by: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx> > > > Acked-by: Arnd Bergmann <arnd@xxxxxxxx> > > [...] > > > diff --git a/include/linux/fcntl.h b/include/linux/fcntl.h > > > index 1b48d9c9a561..297993c92490 100644 > > > --- a/include/linux/fcntl.h > > > +++ b/include/linux/fcntl.h > > > @@ -11,7 +11,7 @@ > > > O_NOATIME | O_CLOEXEC | O_PATH | __O_TMPFILE) > > > > > > #ifndef force_o_largefile > > > -#define force_o_largefile() (BITS_PER_LONG != 32) > > > +#define force_o_largefile() (!IS_ENABLED(CONFIG_ARCH_32BIT_OFF_T)) > > > #endif > > > > I may have confused myself with which off_t is 64-bit here for new > > 32-bit architectures. Are we referring to the glibc definition, the > > kernel one or simply that force_o_largefile() is true by default. > > Because the type off_t for 32-bit kernel builds is still, well, 32-bit. > > > > Otherwise it seems that the first paragraph in the description above > > should read "all new 32-bit ABIs on a 64-bit kernel..." but then > > AArch64/ILP32 is no longer the same as a new, pure 32-bit architecture. > > This is all about userspace off_t types, like Arnd told in the comment > to patch 13. I'll underline it in the comment to the patch. If it's > not enough, I can also rename the config option to > CONFIG_ARCH_32BIT_USER_OFF_T or similar. For me it's too much, but if > you find it reasonable, I'll do it. Just let me know. Thanks for clarification. I had the impression that it should match the kernel's off_t (which is exported in the kernel headers as 32-bit) but compiling with -mabi=ilp32 indeed shows sizeof(off_t) == 8. So that's just a user decision to use loff_t instead and such port shouldn't use any of the syscalls that pass the kernel's off_t. I would rather see the comment in the arch/Kconfig help entry in this patch for future reference. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
