On Wed, 15 Jan 2014 14:57:56 -0800 (PST) David Rientjes <rientjes@xxxxxxxxxx> wrote:
On Wed, 15 Jan 2014, Geert Uytterhoeven wrote:
{,set}page_address() are macros if WANT_PAGE_VIRTUAL.
If !WANT_PAGE_VIRTUAL, they're plain C functions.
If someone calls them with a void *, this pointer is auto-converted to
struct page * if !WANT_PAGE_VIRTUAL, but causes a build failure on
architectures using WANT_PAGE_VIRTUAL (arc, m68k and sparc):
s/sparc/sparc64/
drivers/md/bcache/bset.c: In function _____btree_sort___:
drivers/md/bcache/bset.c:1190: warning: dereferencing ___void *___ pointer
drivers/md/bcache/bset.c:1190: error: request for member ___virtual___ in something not a structure or union
Convert them to static inline functions to fix this. There are already
plenty of users of struct page members inside <linux/mm.h>, so there's no
reason to keep them as macros.
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Tested-by: David Rientjes <rientjes@xxxxxxxxxx>
I'm cringing at the page_address(mempool_alloc(..., GFP_NOIO)) in
drivers/md/bcache/bset.c, though.
Yes, I was staring suspiciously at that as well. Ended up deciding
that I wouldn't have coded it that way, but we should support the
casting.
It's relying on that fact that
mempool_alloc() can never return NULL if __GFP_WAIT but I think this could
have all been avoided with
struct page *page = mempool_alloc(state->pool, GFP_NOIO);
out = page_address(page);
instead of burying the mempool_alloc() in page_address() for what I think
is cleaner code. Owell, it fixes the issue.
And that would make the later virt_to_page() unnecessary.
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