Now that all the in-tree users are converted over to zero_user_page(),
deprecate the old memclear_highpage_flush() call.
Signed-off-by: Nate Diller <nate.diller@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's very common for file systems to need to zero part or all of a page,
the simplist way is just to use kmap_atomic() and memset(). There's
actually a library function in include/linux/highmem.h that does exactly
that, but it's confusingly named memclear_highpage_flush(), which is
descriptive of *how* it does the work rather than what the *purpose* is.
So this patchset renames the function to zero_user_page(), and calls it
from the various places that currently open code it.
This first patch introduces the new function call, and converts all the
core kernel callsites, both the open-coded ones and the old
memclear_highpage_flush() ones. Following this patch is a series of
conversions for each file system individually, per AKPM, and finally a
patch deprecating the old call. The diffstat below shows the entire
patchset.
[akpm@linux-foundation.org: fix a few things]
Signed-off-by: Nate Diller <nate.diller@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://one.firstfloor.org/home/andi/git/linux-2.6: (231 commits)
[PATCH] i386: Don't delete cpu_devs data to identify different x86 types in late_initcall
[PATCH] i386: type may be unused
[PATCH] i386: Some additional chipset register values validation.
[PATCH] i386: Add missing !X86_PAE dependincy to the 2G/2G split.
[PATCH] x86-64: Don't exclude asm-offsets.c in Documentation/dontdiff
[PATCH] i386: avoid redundant preempt_disable in __unlazy_fpu
[PATCH] i386: white space fixes in i387.h
[PATCH] i386: Drop noisy e820 debugging printks
[PATCH] x86-64: Fix allnoconfig error in genapic_flat.c
[PATCH] x86-64: Shut up warnings for vfat compat ioctls on other file systems
[PATCH] x86-64: Share identical video.S between i386 and x86-64
[PATCH] x86-64: Remove CONFIG_REORDER
[PATCH] x86-64: Print type and size correctly for unknown compat ioctls
[PATCH] i386: Remove copy_*_user BUG_ONs for (size < 0)
[PATCH] i386: Little cleanups in smpboot.c
[PATCH] x86-64: Don't enable NUMA for a single node in K8 NUMA scanning
[PATCH] x86: Use RDTSCP for synchronous get_cycles if possible
[PATCH] i386: Add X86_FEATURE_RDTSCP
[PATCH] i386: Implement X86_FEATURE_SYNC_RDTSC on i386
[PATCH] i386: Implement alternative_io for i386
...
Fix up trivial conflict in include/linux/highmem.h manually.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert kmap_atomic() in the non-highmem case from a macro to a static
inline function, for better type-checking and the ability to pass void
pointers instead of struct page pointers.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Xen and VMI both have special requirements when mapping a highmem pte
page into the kernel address space. These can be dealt with by adding
a new kmap_atomic_pte() function for mapping highptes, and hooking it
into the paravirt_ops infrastructure.
Xen specifically wants to map the pte page RO, so this patch exposes a
helper function, kmap_atomic_prot, which maps the page with the
specified page protections.
This also adds a kmap_flush_unused() function to clear out the cached
kmap mappings. Xen needs this to clear out any potential stray RW
mappings of pages which will become part of a pagetable.
[ Zach - vmi.c will need some attention after this patch. It wasn't
immediately obvious to me what needs to be done. ]
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Zachary Amsden <zach@vmware.com>
Since get_user_pages() may be used with processes other than the
current process and calls flush_anon_page(), flush_anon_page() has to
cope in some way with non-current processes.
It may not be appropriate, or even desirable to flush a region of
virtual memory cache in the current process when that is different to
the process that we want the flush to occur for.
Therefore, pass the vma into flush_anon_page() so that the architecture
can work out whether the 'vmaddr' is for the current process or not.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
To allow a more effective copy_user_highpage() on certain architectures,
a vma argument is added to the function and cow_user_page() allowing
the implementation of these functions to check for the VM_EXEC bit.
The main part of this patch was originally written by Ralf Baechle;
Atushi Nemoto did the the debugging.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Problem:
1. There is a process containing two thread (T1 and T2). The
thread T1 calls fork(). Then dup_mmap() function called on T1 context.
static inline int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
...
flush_cache_mm(current->mm);
... /* A */
(write-protect all Copy-On-Write pages)
... /* B */
flush_tlb_mm(current->mm);
...
2. When preemption happens between A and B (or on SMP kernel), the
thread T2 can run and modify data on COW pages without page fault
(modified data will stay in cache).
3. Some time after fork() completed, the thread T2 may cause a page
fault by write-protect on a COW page.
4. Then data of the COW page will be copied to newly allocated
physical page (copy_cow_page()). It reads data via kernel mapping.
The kernel mapping can have different 'color' with user space
mapping of the thread T2 (dcache aliasing). Therefore
copy_cow_page() will copy stale data. Then the modified data in
cache will be lost.
In order to allow architecture code to deal with this problem allow
architecture code to override copy_user_highpage() by defining
__HAVE_ARCH_COPY_USER_HIGHPAGE in <asm/page.h>.
The main part of this patch was originally written by Ralf Baechle;
Atushi Nemoto did the the debugging.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make kmap_atomic/kunmap_atomic denote a pagefault disabled scope. All non
trivial implementations already do this anyway.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Move totalhigh_pages and nr_free_highpages() into highmem.c/.h
Move the totalhigh_pages definition into highmem.c/.h. Move the
nr_free_highpages function into highmem.c
[yoichi_yuasa@tripeaks.co.jp: build fix]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Give non-highmem architectures access to the kmap API for the purposes of
overriding (this is what the attached patch does).
The proposal is that we should now require all architectures with coherence
issues to manage data coherence via the kmap/kunmap API. Thus driver
writers never have to write code like
kmap(page)
modify data in page
flush_kernel_dcache_page(page)
kunmap(page)
instead, kmap/kunmap will manage the coherence and driver (and filesystem)
writers don't need to worry about how to flush between kmap and kunmap.
For most architectures, the page only needs to be flushed if it was
actually written to *and* there are user mappings of it, so the best
implementation looks to be: clear the page dirty pte bit in the kernel page
tables on kmap and on kunmap, check page->mappings for user maps, and then
the dirty bit, and only flush if it both has user mappings and is dirty.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We have a problem in a lot of emulated storage in that it takes a page from
get_user_pages() and does something like
kmap_atomic(page)
modify page
kunmap_atomic(page)
However, nothing has flushed the kernel cache view of the page before the
kunmap. We need a lightweight API to do this, so this new API would
specifically be for flushing the kernel cache view of a user page which the
kernel has modified. The driver would need to add
flush_kernel_dcache_page(page) before the final kunmap.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently, get_user_pages() returns fully coherent pages to the kernel for
anything other than anonymous pages. This is a problem for things like
fuse and the SCSI generic ioctl SG_IO which can potentially wish to do DMA
to anonymous pages passed in by users.
The fix is to add a new memory management API: flush_anon_page() which
is used in get_user_pages() to make anonymous pages coherent.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch provides the interfaces necessary to read the dump contents,
treating it as a high memory device.
Signed off by Hariprasad Nellitheertha <hari@in.ibm.com>
Signed-off-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
