Re: AZFS file system proposal

On Wed, 2008-07-09 at 11:14 +0200, Maxim Shchetynin wrote:

Am Wed, 09 Jul 2008 18:58:38 +1000
schrieb Benjamin Herrenschmidt [off-list ref]:

quoted

On Tue, 2008-07-01 at 16:59 +0200, Arnd Bergmann wrote:

quoted

I wouldn't hold up merging the file system for this problem, but
until it is solved, the Kconfig entry should probably have
a "depends on PPC".

Better, use an ifdef for powerpc flags, and #else to pgprot_noncached.

Thank you Ben. Then, how about this?

azfs_mmap(struct file *file, struct vm_area_struct *vma)
{
...
...
...
#ifdef CONFIG_PPC
	pgprot_t page_prot;
#endif
...
...
...
#ifdef CONFIG_PPC
	page_prot = pgprot_val(vma->vm_page_prot);
	page_prot |= (_PAGE_NO_CACHE | _PAGE_RW);
	page_prot &= ~_PAGE_GUARDED;
	vma->vm_page_prot = __pgprot(page_prot);
#else
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
#endif
...

I'd rather do

	pgprot_t  prot;

#ifdef CONFIG_PPC
	prot = <whatever>
#else
	prot = pgprot_noncached(...)
#endif
	vma->vm_page_prot = prot;

To limit the number of ifdef's

Cheers,
Ben.