On Wed, 29 Mar 2017 06:57:06 +0100 Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > The patchset currently in vfs.git#work.uaccess is the result; > there's more work to do, but it takes care of a large part of the > problems. About 2.8KLoc removed, a lot of cruft is gone and semantics > is hopefully in sync now. All but two architectures (ia64 and metag) > had been switched to new mechanism; for these two I'm afraid that I'll > need serious help from maintainers. I have tested the code in vfs.git#work.uaccess and in principle it works for s390. I found one bug which would return an incorrect result for copy_from_user if the access faults on the last page of the copy. In that case the new code would return 0 instead of the remaining bytes. This patch snippet should fix it, please just merge it into commit "s390: get rid of zeroing, switch to RAW_COPY_USER" diff --git a/arch/s390/lib/uaccess.c b/arch/s390/lib/uaccess.c index b55172c..1e5bb2b 100644 --- a/arch/s390/lib/uaccess.c +++ b/arch/s390/lib/uaccess.c @@ -35,7 +35,7 @@ static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */ " slgr %4,%1\n" " clgr %0,%4\n" /* copy crosses next page boundary? */ - " jnh 4f\n" + " jnh 5f\n" "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n" "7: slgr %0,%4\n" " j 5f\n" -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.
