The patch titled
mm: uncached vma support with writenotify
has been added to the -mm tree. Its filename is
mm-uncached-vma-support-with-writenotify.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: mm: uncached vma support with writenotify
From: Magnus Damm <damm@xxxxxxxxxxxxx>
Modify the generic mmap() code to keep the cache attribute in
vma->vm_page_prot regardless if writenotify is enabled or not. Without
this patch the cache configuration selected by f_op->mmap() is overwritten
if writenotify is enabled, making it impossible to keep the vma uncached.
Needed by drivers such as drivers/video/sh_mobile_lcdcfb.c which uses
deferred io together with uncached memory.
Signed-off-by: Magnus Damm <damm@xxxxxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Cc: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Cc: Jaya Kumar <jayakumar.lkml@xxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff -puN mm/mmap.c~mm-uncached-vma-support-with-writenotify mm/mmap.c
--- a/mm/mmap.c~mm-uncached-vma-support-with-writenotify
+++ a/mm/mmap.c
@@ -1220,8 +1220,20 @@ munmap_back:
goto free_vma;
}
- if (vma_wants_writenotify(vma))
+ if (vma_wants_writenotify(vma)) {
+ pgprot_t pprot = vma->vm_page_prot;
+
+ /* Can vma->vm_page_prot have changed??
+ *
+ * Answer: Yes, drivers may have changed it in their
+ * f_op->mmap method.
+ *
+ * Ensures that vmas marked as uncached stay that way.
+ */
vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
+ if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot)))
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+ }
vma_link(mm, vma, prev, rb_link, rb_parent);
file = vma->vm_file;
_
Patches currently in -mm which might be from damm@xxxxxxxxxxxxx are
linux-next.patch
clocksource-add-argument-to-resume-callback.patch
clocksource-start-cmt-at-clocksource-resume.patch
mm-uncached-vma-support-with-writenotify.patch
mmc-let-tmio-mmc-use-dev_name-with-request_irq.patch
mmc-remove-const-from-tmio-mmc-platform-data-v2.patch
mmc-balance-tmio-mmc-cell-enable-disable-calls.patch
spi-superh-msiof-spi-master-driver.patch
spi-superh-msiof-spi-master-driver-update.patch
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