Messages in this thread Patch in this message | | | Date | Thu, 9 Sep 2004 17:44:53 +0200 | From | Jens Axboe <> | Subject | Re: [patch][9/9] block: remove bio walking |
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On Thu, Sep 09 2004, Russell King wrote: > Essentially, kernel PIO writes data into the page cache, and that action > may leave data in the CPU's caches. Since the kernels mappings may not > be coherent with mappings in userspace, data written to the kernel > mappings may remain in the data cache, and stale data would be visible > to user space. > > There has been talk about using flush_dcache_page() to resolve > this issue, but I'm not sure what the outcome was. Certainly > flush_dcache_page() is supposed to be used before the data in the > kernels page cache is read or written.
Have you ever tested bouncing on arm? It seems to be lacking a flush_dcache_page() indeed, how does this look?
===== mm/highmem.c 1.51 vs edited ===== --- 1.51/mm/highmem.c 2004-07-29 06:58:32 +02:00 +++ edited/mm/highmem.c 2004-09-09 17:44:14 +02:00 @@ -301,6 +301,7 @@ vfrom = page_address(fromvec->bv_page) + tovec->bv_offset; bounce_copy_vec(tovec, vfrom); + flush_dcache_page(tovec->bv_page); } } -- Jens Axboe
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