Re: [RFC PATCH 08/35] Add Xen-specific memory management definitions

[Christian Limpach <Christian.Limpach@cl.cam.ac.uk>]

On Tue, May 09, 2006 at 07:49:45AM -0700, Martin J. Bligh wrote:
> 
> >+#define virt_to_ptep(__va)						\
> >+({									\
> >+	pgd_t *__pgd = pgd_offset_k((unsigned long)(__va));		\
> >+	pud_t *__pud = pud_offset(__pgd, (unsigned long)(__va));	\
> >+	pmd_t *__pmd = pmd_offset(__pud, (unsigned long)(__va));	\
> >+	pte_offset_kernel(__pmd, (unsigned long)(__va));		\
> >+})
> 
> Do we really need yet another function to do this?
> Especially one in a mult-line #define instead of a real function call,
> and that doesn't seem to error check at each step?

Indeed, I'll use lookup_address instead.

> >+
> >+#define arbitrary_virt_to_machine(__va)				 \
> >+({									\
> >+	maddr_t m = (maddr_t)pte_mfn(*virt_to_ptep(__va)) << PAGE_SHIFT;\
> >+	m | ((unsigned long)(__va) & (PAGE_SIZE-1));			\
> >+})
> >+
> >+#define make_lowmem_page_readonly(va, feature) do {		\
> >+	pte_t *pte;						\
> >+	int rc;							\
> >+								\
> >+	if (xen_feature(feature))				\
> >+		return;						\
> >+								\
> >+	pte = virt_to_ptep(va);					\
> >+	rc = HYPERVISOR_update_va_mapping(			\
> >+		(unsigned long)va, pte_wrprotect(*pte), 0);	\
> >+	BUG_ON(rc);						\
> >+} while (0)
> 
> Things this long should definitely not be #defines.

I've changed these to be functions and moved them into a .c file
under arch/i386/mach-xen.

    christian

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