Date: Thu, 13 Jan 2011 10:12:17 +0100 From: Clemens Ladisch Subject: firewire: ohci: fix compilation on arches without PAGE_KERNEL_RO PAGE_KERNEL_RO is not available on all architectures, so its use in the new AR code broke compilation on sparc64. Because the read-only mapping was just a debugging aid, just use PAGE_KERNEL instead. Signed-off-by: Clemens Ladisch James Bottomley wrote: > On Thu, 2011-01-13 at 08:27 +0100, Clemens Ladisch wrote: >> firewire: ohci: fix compilation on arches without PAGE_KERNEL_RO, e.g. sparc >> >> PAGE_KERNEL_RO is not available on all architectures, so its use in the >> new AR code broke compilation on sparc64. >> >> Because the R/O mapping is only used to catch drivers that try to write >> to the reception buffer and not actually required for correct operation, >> we can just use a normal PAGE_KERNEL mapping where _RO is not available. [...] >> +/* >> + * For archs where PAGE_KERNEL_RO is not supported; >> + * mapping the AR buffers readonly for the CPU is just a debugging aid. >> + */ >> +#ifndef PAGE_KERNEL_RO >> +#define PAGE_KERNEL_RO PAGE_KERNEL >> +#endif > > This might cause interesting issues on sparc64 if it ever acquired a > PAGE_KERNEL_RO. Sparc64 has extern pgprot_t for it's PAGE_KERNEL types > rather than #defines, so the #ifdef check wouldn't see this. > > I think either PAGE_PROT_RO becomes part of our arch API (so all > architectures are forced to add it), or, if it's not part of the API, > ohci isn't entitled to use it. The latter seems simplest since you have > no real use for write protection anyway. Reported-by: Andrew Morton Signed-off-by: Stefan Richter --- drivers/firewire/ohci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: b/drivers/firewire/ohci.c =================================================================== --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -961,7 +961,7 @@ static int ar_context_init(struct ar_con for (i = 0; i < AR_WRAPAROUND_PAGES; i++) pages[AR_BUFFERS + i] = ctx->pages[i]; ctx->buffer = vm_map_ram(pages, AR_BUFFERS + AR_WRAPAROUND_PAGES, - -1, PAGE_KERNEL_RO); + -1, PAGE_KERNEL); if (!ctx->buffer) goto out_of_memory;