linux.git/mm/memory.c, branch v2.6.31

mm: Pass virtual address to [__]p{te,ud,md}_free_tlb()

2009-07-27T19:10:38+00:00

mm: Pass virtual address to [__]p{te,ud,md}_free_tlb()

Upcoming paches to support the new 64-bit "BookE" powerpc architecture
will need to have the virtual address corresponding to PTE page when
freeing it, due to the way the HW table walker works.

Basically, the TLB can be loaded with "large" pages that cover the whole
virtual space (well, sort-of, half of it actually) represented by a PTE
page, and which contain an "indirect" bit indicating that this TLB entry
RPN points to an array of PTEs from which the TLB can then create direct
entries. Thus, in order to invalidate those when PTE pages are deleted,
we need the virtual address to pass to tlbilx or tlbivax instructions.

The old trick of sticking it somewhere in the PTE page struct page sucks
too much, the address is almost readily available in all call sites and
almost everybody implemets these as macros, so we may as well add the
argument everywhere. I added it to the pmd and pud variants for consistency.

Signed-off-by: Benjamin Herrenschmidt 
Acked-by: David Howells  [MN10300 & FRV]
Acked-by: Nick Piggin 
Acked-by: Martin Schwidefsky  [s390]
Signed-off-by: Linus Torvalds

clarify get_user_pages() prototype

2009-06-25T18:22:13+00:00

Currently the 4th parameter of get_user_pages() is called len, but its
in pages, not bytes. Rename the thing to nr_pages to avoid future
confusion.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Linus Torvalds

mm: pass mm to grab_swap_token

2009-06-23T19:50:05+00:00

If a kthread happens to use get_user_pages() on an mm (as KSM does),
there's a chance that it will end up trying to read in a swap page, then
oops in grab_swap_token() because the kthread has no mm: GUP passes down
the right mm, so grab_swap_token() ought to be using it.

We have not identified a stronger case than KSM's daemon (not yet in
mainline), but the issue must have come up before, since RHEL has included
a fix for this for years (though a different fix, they just back out of
grab_swap_token if current->mm is unset: which is what we first proposed,
but using the right mm here seems more correct).

Reported-by: Izik Eidus 
Signed-off-by: Johannes Weiner 
Signed-off-by: Hugh Dickins 
Acked-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: don't rely on flags coincidence

2009-06-23T18:23:33+00:00

Indeed FOLL_WRITE matches FAULT_FLAG_WRITE, matches GUP_FLAGS_WRITE,
and it's tempting to devise a set of Grand Unified Paging flags;
but not today.  So until then, let's rely upon the compiler to spot
the coincidence, "rather than have that subtle dependency and a
comment for it" - as you remarked in another context yesterday.

Signed-off-by: Hugh Dickins 
Acked-by: Wu Fengguang 
Signed-off-by: Linus Torvalds

Move FAULT_FLAG_xyz into handle_mm_fault() callers

2009-06-21T20:08:22+00:00

This allows the callers to now pass down the full set of FAULT_FLAG_xyz
flags to handle_mm_fault().  All callers have been (mechanically)
converted to the new calling convention, there's almost certainly room
for architectures to clean up their code and then add FAULT_FLAG_RETRY
when that support is added.

Signed-off-by: Linus Torvalds

Remove internal use of 'write_access' in mm/memory.c

2009-06-21T20:06:05+00:00

The fault handling routines really want more fine-grained flags than a
single "was it a write fault" boolean - the callers will want to set
flags like "you can return a retry error" etc.

And that's actually how the VM works internally, but right now the
top-level fault handling functions in mm/memory.c all pass just the
'write_access' boolean around.

This switches them over to pass around the FAULT_FLAG_xyzzy 'flags'
variable instead.  The 'write_access' calling convention still exists
for the exported 'handle_mm_fault()' function, but that is next.

Signed-off-by: Linus Torvalds

mm: introduce follow_pfn()

2009-06-17T02:47:40+00:00

Analoguous to follow_phys(), add a helper that looks up the PFN at a
user virtual address in an IO mapping or a raw PFN mapping.

Signed-off-by: Johannes Weiner 
Cc: Christoph Hellwig 
Acked-by: Magnus Damm 
Cc: Hans Verkuil 
Cc: Paul Mundt 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: use generic follow_pte() in follow_phys()

2009-06-17T02:47:40+00:00

Signed-off-by: Johannes Weiner 
Cc: Christoph Hellwig 
Acked-by: Magnus Damm 
Cc: Hans Verkuil 
Cc: Paul Mundt 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: introduce follow_pte()

2009-06-17T02:47:39+00:00

A generic readonly page table lookup helper to map an address space and an
address from it to a pte.

Signed-off-by: Johannes Weiner 
Cc: Christoph Hellwig 
Acked-by: Magnus Damm 
Cc: Hans Verkuil 
Cc: Paul Mundt 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: clean up get_user_pages_fast() documentation

2009-06-17T02:47:30+00:00

Move more documentation for get_user_pages_fast into the new kerneldoc comment.
Add some comments for get_user_pages as well.

Also, move get_user_pages_fast declaration up to get_user_pages. It wasn't
there initially because it was once a static inline function.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Nick Piggin 
Cc: Andy Grover 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds