> On Tue, Nov 25, 2014 at 12:43:25PM +0100, David Hildenbrand wrote: > > Whenever we have pagefaults disabled, we have to use the atomic variants of > > (set|get)_user and copy_(from|to)_user. > > > > Signed-off-by: David Hildenbrand <d...@linux.vnet.ibm.com> > > --- > > arch/powerpc/sysdev/fsl_pci.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c > > index 65d2ed4..c0af4ef 100644 > > --- a/arch/powerpc/sysdev/fsl_pci.c > > +++ b/arch/powerpc/sysdev/fsl_pci.c > > @@ -1025,7 +1025,7 @@ int fsl_pci_mcheck_exception(struct pt_regs *regs) > > if (is_in_pci_mem_space(addr)) { > > if (user_mode(regs)) { > > pagefault_disable(); > > - ret = get_user(regs->nip, &inst); > > + ret = __get_user_inatomic(regs->nip, &inst); > > pagefault_enable(); > > } else { > > ret = probe_kernel_address(regs->nip, inst); > > Please post a non-RFC version if you're ready for this to be merged. > > -Scott >
Hi Scott, actually this patch was wrong. We are allowed to use the non-atomic variants during pagefault_disable(). The semantics of get_user()/set_user() then change - they will not sleep. To reenable the might_sleep checks() in might_fault() makes it necessary to count the levels of pagefault_disable() calls, to distinguish it from oridnary preempt_disable() calls. I've got another patchset out there that deals with this problem and is able to distinguish between them. The interest in this feature just doesn't seem to be very high :) So you can safely ignore this patch. David _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev