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| author | Clemens Ladisch <clemens@ladisch.de> | 2011-01-13 10:12:17 +0100 |
|---|---|---|
| committer | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2011-01-13 15:48:29 +0100 |
| commit | 1427130425c1239d977e8891c3a8923f53a6e352 (patch) | |
| tree | 940207bbaf155d7ed36c6b8fab201dae6773ec1f | |
| parent | 410cf2bd3dc6ec1ed9e1b36b25b9d7aa927ed14e (diff) | |
| download | linux-stable-1427130425c1239d977e8891c3a8923f53a6e352.tar.gz linux-stable-1427130425c1239d977e8891c3a8923f53a6e352.tar.bz2 linux-stable-1427130425c1239d977e8891c3a8923f53a6e352.zip | |
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 <clemens@ladisch.de>
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 <akpm@linux-foundation.org>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
| -rw-r--r-- | drivers/firewire/ohci.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c index d77d120ddc25..bd3c61b6dd8d 100644 --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -961,7 +961,7 @@ static int ar_context_init(struct ar_context *ctx, struct fw_ohci *ohci, 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; |