Messages in this thread | | | Date | Sun, 27 Oct 2013 15:18:17 +0100 | From | Simon Baatz <> | Subject | Re: ARM/kirkwood: v3.12-rc6: kernel BUG at mm/util.c:390! |
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Hi Russell,
On Sun, Oct 27, 2013 at 01:53:44PM +0000, Russell King - ARM Linux wrote: > On Sun, Oct 27, 2013 at 09:16:53PM +0800, Ming Lei wrote: > > On Sun, Oct 27, 2013 at 8:50 PM, Aaro Koskinen <aaro.koskinen@iki.fi> wrote: > > > > So... > > flush_kernel_dcache_page() is expected to take a struct page pointer. > This struct page pointer is part of the kernel's array of struct pages > which identifies every single physical page under the control of the > kernel. > > Arguably, it should not crash if passed a page which has been allocated > to the slab cache; as this is not a page cache page, > flush_kernel_dcache_page() should merely ignore the call to it and > simply return on these. So this makes total sense:
In this respect, flush_kernel_dcache_page() is following flush_dcache_page(). For example in crypto/scatterwalk.c:
static void scatterwalk_pagedone(struct scatter_walk *walk, int out, unsigned int more) { if (out) { struct page *page;
page = sg_page(walk->sg) + ((walk->offset - 1) >> PAGE_SHIFT); if (!PageSlab(page)) flush_dcache_page(page); } ...
or in drivers/ata/libata-sff.c:
... if (!do_write && !PageSlab(page)) flush_dcache_page(page); ...
(Probably, both cases should have used flush_kernel_dcache_page() in the first place). If we say that this check belongs in flush_kernel_dcache_page() we should also put it into flush_dcache_page(), no?
- Simon
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