This improves the might_fault annotations used by uaccess routines: 1. The only reason uaccess routines might sleep is if they fault. Make this explicit for all architectures. 2. Accesses (e.g through socket ops) to kernel memory with KERNEL_DS like net/sunrpc does will never sleep. Remove an unconditinal might_sleep in the inline might_fault in kernel.h (used when PROVE_LOCKING is not set). 3. Accesses with pagefault_disable return EFAULT but won't cause caller to sleep. Check for that and avoid might_sleep when PROVE_LOCKING is set. I'd like these changes to go in for the benefit of the vhost driver where we want to call socket ops under a spinlock, and fall back on slower thread handler on error. Please review, and consider for 3.11. If the changes look good, what's the best way to merge them? Maybe core/locking makes sense? Note on arch code updates: I tested x86_64 code. Other architectures were build-tested. I don't have cross-build environment for arm64, tile, microblaze and mn10300 architectures. The changes look safe enough but would appreciate review/acks from arch maintainers. Version 1 of this change was titled x86: uaccess s/might_sleep/might_fault/ Changes from v1: add more architectures fix might_fault() scheduling differently depending on CONFIG_PROVE_LOCKING, as suggested by Ingo Michael S. Tsirkin (10): asm-generic: uaccess s/might_sleep/might_fault/ arm64: uaccess s/might_sleep/might_fault/ frv: uaccess s/might_sleep/might_fault/ m32r: uaccess s/might_sleep/might_fault/ microblaze: uaccess s/might_sleep/might_fault/ mn10300: uaccess s/might_sleep/might_fault/ powerpc: uaccess s/might_sleep/might_fault/ tile: uaccess s/might_sleep/might_fault/ x86: uaccess s/might_sleep/might_fault/ kernel: might_fault does not imply might_sleep arch/arm64/include/asm/uaccess.h | 4 ++-- arch/frv/include/asm/uaccess.h | 4 ++-- arch/m32r/include/asm/uaccess.h | 12 ++++++------ arch/microblaze/include/asm/uaccess.h | 6 +++--- arch/mn10300/include/asm/uaccess.h | 4 ++-- arch/powerpc/include/asm/uaccess.h | 16 ++++++++-------- arch/tile/include/asm/uaccess.h | 2 +- arch/x86/include/asm/uaccess_64.h | 2 +- include/asm-generic/uaccess.h | 10 +++++----- include/linux/kernel.h | 1 - mm/memory.c | 14 +++++++++----- 11 files changed, 39 insertions(+), 36 deletions(-) Thanks, -- MST -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
