Nobody uses swiotlb_arch_range_needs_mapping().
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: NBecky Bruce <beckyb@kernel.crashing.org>

Nobody uses swiotlb_alloc().
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: NBecky Bruce <beckyb@kernel.crashing.org>

Nobody uses swiotlb_alloc_boot().
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: NBecky Bruce <beckyb@kernel.crashing.org>

Add a hwdev argument that is needed on some architectures
in order to access a per-device offset that is taken into
account when producing a physical address (also needed to
get from bus address to virtual address because the physical
address is an intermediate step).

Also make swiotlb_bus_to_virt weak so architectures can
override it.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Cc: jeremy@goop.org
Cc: ian.campbell@citrix.com
LKML-Reference: <1239199761-22886-8-git-send-email-galak@kernel.crashing.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Right now both swiotlb_sync_single_range and swiotlb_sync_sg
were duplicating the code in swiotlb_sync_single.  Just call it
instead.  Also rearrange the sync_single code for readability.

Note that the swiotlb_sync_sg code was previously doing
a complicated comparison to determine if an addresses needed
to be unmapped where a simple is_swiotlb_buffer() call
would have sufficed.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Cc: jeremy@goop.org
Cc: ian.campbell@citrix.com
LKML-Reference: <1239199761-22886-7-git-send-email-galak@kernel.crashing.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Previously, swiotlb_unmap_page and swiotlb_unmap_sg were
duplicating very similar code.  Refactor that code into a
new unmap_single and unmap_single use do_unmap_single.

Note that the swiotlb_unmap_sg code was previously doing
a complicated comparison to determine if an addresses needed
to be unmapped where a simple is_swiotlb_buffer() call
would have sufficed.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Cc: jeremy@goop.org
Cc: ian.campbell@citrix.com
LKML-Reference: <1239199761-22886-6-git-send-email-galak@kernel.crashing.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Some architectures require additional checking to determine
if a device can dma to an address and need to provide their
own address_needs_mapping..
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Cc: jeremy@goop.org
Cc: ian.campbell@citrix.com
LKML-Reference: <1239199761-22886-5-git-send-email-galak@kernel.crashing.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The current code calls virt_to_phys() on address that might
be in highmem, which is bad.  This wasn't needed, anyway, because
we already have the physical address we need.

Get rid of the now-unused virtual address as well.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Cc: jeremy@goop.org
Cc: ian.campbell@citrix.com
LKML-Reference: <1239199761-22886-4-git-send-email-galak@kernel.crashing.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Squash a build warning seen on 32-bit powerpc caused by
calling min() with 2 different types. Use min_t() instead.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Cc: jeremy@goop.org
Cc: ian.campbell@citrix.com
LKML-Reference: <1239199761-22886-3-git-send-email-galak@kernel.crashing.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

swiotlb_map/unmap_single are now swiotlb_map/unmap_page;
trivially change all the comments to reference new names.

Also, there were some comments that should have been
referring to just plain old map_single, not swiotlb_map_single;
fix those as well.

Also change a use of the word "pointer", when what is
referred to is actually a dma/physical address.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Acked-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>
Cc: jeremy@goop.org
Cc: ian.campbell@citrix.com
LKML-Reference: <1239199761-22886-2-git-send-email-galak@kernel.crashing.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Replace all DMA_32BIT_MASK macro with DMA_BIT_MASK(32)

Signed-off-by: Yang Hongyang<yanghy@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Scatterlists containing HighMem pages do not have a useful virtual
address. Use the physical address instead.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The swiotlb_arch_range_needs_mapping() hook should take a physical
address rather than a virtual address in order to support highmem pages.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This adds swiotlb_map_page and swiotlb_unmap_page to lib/swiotlb.c and
remove IA64 and X86's swiotlb_map_page and swiotlb_unmap_page.

This also removes unnecessary swiotlb_map_single, swiotlb_map_single_attrs,
swiotlb_unmap_single and swiotlb_unmap_single_attrs.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This converts X86 and IA64 to use include/linux/dma-mapping.h.

It's a bit large but pretty boring. The major change for X86 is
converting 'int dir' to 'enum dma_data_direction dir' in DMA mapping
operations. The major changes for IA64 is using map_page and
unmap_page instead of map_single and unmap_single.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

There's no point in including the linux/swiotlb.h header twice in
lib/swiotlb.c - this patch gets rid of the unneeded include.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup, reduce kernel size a bit

The current kernel build warns:

    WARNING: vmlinux.o(.text+0x11458): Section mismatch in reference from the function swiotlb_alloc_boot() to the function .init.text:__alloc_bootmem_low()
    The function swiotlb_alloc_boot() references
    the function __init __alloc_bootmem_low().
    This is often because swiotlb_alloc_boot lacks a __init
    annotation or the annotation of __alloc_bootmem_low is wrong.

    WARNING: vmlinux.o(.text+0x1011f2): Section mismatch in reference from the function swiotlb_late_init_with_default_size() to the function .init.text:__alloc_bootmem_low()
    The function swiotlb_late_init_with_default_size() references
    the function __init __alloc_bootmem_low().
    This is often because swiotlb_late_init_with_default_size lacks a __init
    annotation or the annotation of __alloc_bootmem_low is wrong.

and indeed the functions calling __alloc_bootmem_low() can be marked
__init as well.
Signed-off-by: NRoland Dreier <rolandd@cisco.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

swiotlb uses EXPORT_SYMBOL in an inconsistent way. Some functions use
EXPORT_SYMBOL at the end of functions. Some use it at the end of
swiotlb.c.

This cleans up swiotlb to use EXPORT_SYMBOL in a consistent way (at
the end of functions).
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: extend code for highmem - existing users unaffected

On highmem systems, the original dma buffer might not
have a virtual mapping - we need to kmap it in to perform
the bounce.  Extract the code that does the actual
copy into a function that does the kmap if highmem
is enabled, and default to the normal swiotlb memcpy
if not.

[ ported by Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> ]
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: refactor code, cleanup

When we enable swiotlb for platforms that support HIGHMEM, we
can no longer store the virtual address of the original dma
buffer, because that buffer might not have a permament mapping.

Change the swiotlb code to instead store the physical address of
the original buffer.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: extend functions with a (yet unused) parameter, update callsites

Some architectures need it - in preparation for highmem swiotlb.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: clean up swiotlb printks

Remove duplicated swiotlb info printing, and make it more detailed.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: prepare the swiotlb code for HighMem struct pages

This requires us to treat DMA regions in terms of page+offset rather
than virtual addressing since a HighMem page may not have a mapping.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: generalize IO bounce memcpys
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: generalize the sw-IOTLB range checks

Some architectures require special rules to determine whether a range
needs mapping or not.  This adds a weak function for architectures to
override.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: generalize phys<->bus<->phys conversions in the swiotlb code

Architectures may need to override these conversions. Implement a
__weak hook point containing the default implementation.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: generalize swiotlb allocation code

Architectures may need to allocate memory specially for use with
the swiotlb.  Create the weak function swiotlb_alloc_boot() and
swiotlb_alloc() defaulting to the current behaviour.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix DMA buffer allocation coherency bug in certain configs

This patch fixes swiotlb to use dev->coherent_dma_mask in
swiotlb_alloc_coherent().

coherent_dma_mask is a subset of dma_mask (equal to it most of
the time), enumerating the address range that a given device
is able to DMA to/from in a cache-coherent way.

But currently, swiotlb uses dev->dma_mask in alloc_coherent()
implicitly via address_needs_mapping(), but alloc_coherent is really
supposed to use coherent_dma_mask.

This bug could break drivers that uses smaller coherent_dma_mask than
dma_mask (though the current code works for the majority that use the
same mask for coherent_dma_mask and dma_mask).
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: tony.luck@intel.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

swiotlb_alloc_coherent calls panic() when allocated swiotlb pages is
not fit for a device's dma mask. However, alloc_coherent failure is
not a disaster at all. AFAIK, none of other x86 and IA64 IOMMU
implementations don't crash in case of alloc_coherent failure.

There are some drivers that don't check alloc_coherent failure but not
many (about ten and I've already started to fix some of
them). alloc_coherent returns NULL in case of failure so it's likely
that these guilty drivers crash immediately. So swiotlb doesn't need
to call panic() just for them.
Reported-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Tested-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

swiotlb can use dma_get_mask() instead of the homegrown function.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: tony.luck@intel.com
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This fixes a SWIOTLB oops

With SWIOTLB being enabled and straight-forward page allocation
failure [1], the swiotlb_alloc_coherent fall-back path hits an
issue [2], resulting in my webcam failing to work.

At the time of oops, RDI is clearly a pointer to a structure which
has arrived as NULL, leading to the typo in swiotlb_map_single's
callsite arguments.

Correctly passing the device structure [3] addresses the issue and
gets my webcam working again (the allocation failure still occuring).

 --- [1]

skype: page allocation failure. order:3, mode:0x1
Pid: 5895, comm: skype Not tainted 2.6.27-rc6-235c-debug #1

Call Trace:
 [<ffffffff802b7cf0>] __alloc_pages_internal+0x4a0/0x5d0
 [<ffffffff802d5ddd>] alloc_pages_current+0xad/0x110
 [<ffffffff802b4ccd>] __get_free_pages+0x1d/0x60
 [<ffffffff8046cd39>] swiotlb_alloc_coherent+0x49/0x180
 [<ffffffff80212731>] dma_alloc_coherent+0x281/0x310
 [<ffffffff805621c0>] hcd_buffer_alloc+0x50/0x90
 [<ffffffff805547fd>] usb_buffer_alloc+0x2d/0x40
 [<ffffffffa0056763>] uvc_alloc_urb_buffers+0x53/0xf0 [uvcvideo]
 [<ffffffffa0056958>] uvc_init_video+0x158/0x3e0 [uvcvideo]
 [<ffffffffa0056c17>] uvc_video_enable+0x37/0x80 [uvcvideo]
 [<ffffffffa0055853>] uvc_v4l2_do_ioctl+0x723/0x1260 [uvcvideo]
 [<ffffffff8026dd61>] ? trace_hardirqs_off_caller+0x21/0xc0
 [<ffffffff8026dd61>] ? trace_hardirqs_off_caller+0x21/0xc0
 [<ffffffffa0032c9f>] video_usercopy+0x19f/0x390 [videodev]
 [<ffffffffa0055130>] ? uvc_v4l2_do_ioctl+0x0/0x1260 [uvcvideo]
 [<ffffffff8026d0ce>] ? put_lock_stats+0xe/0x30
 [<ffffffffa0054dad>] uvc_v4l2_ioctl+0x4d/0x80 [uvcvideo]
 [<ffffffffa0045083>] native_ioctl+0x83/0x90 [compat_ioctl32]
 [<ffffffffa004534e>] v4l_compat_ioctl32+0x2be/0x1da4 [compat_ioctl32]
 [<ffffffff806aad21>] ? do_page_fault+0x3d1/0xae0
 [<ffffffff80270ccd>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff80270c59>] ? trace_hardirqs_on_caller+0x149/0x1b0
 [<ffffffff80270ccd>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff80329afa>] compat_sys_ioctl+0x8a/0x3c0
 [<ffffffff806a700d>] ? trace_hardirqs_off_thunk+0x3a/0x3c
 [<ffffffff8022f816>] sysenter_dispatch+0x7/0x2c
 [<ffffffff806a6fce>] ? trace_hardirqs_on_thunk+0x3a/0x3f

Mem-Info:
Node 0 DMA per-cpu:
CPU    0: hi:    0, btch:   1 usd:   0
CPU    1: hi:    0, btch:   1 usd:   0
Node 0 DMA32 per-cpu:
CPU    0: hi:  186, btch:  31 usd:   3
CPU    1: hi:  186, btch:  31 usd:   0
Node 0 Normal per-cpu:
CPU    0: hi:  186, btch:  31 usd:  23
CPU    1: hi:  186, btch:  31 usd: 179
Active:78545 inactive:48683 dirty:31 writeback:0 unstable:2
 free:830202 slab:17516 mapped:17473 pagetables:3496 bounce:0
Node 0 DMA free:36kB min:28kB low:32kB high:40kB active:0kB
inactive:0kB present:15156kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 3207 3956 3956
Node 0 DMA32 free:3197192kB min:6512kB low:8140kB high:9768kB
active:0kB inactive:0kB present:3284896kB pages_scanned:0
all_unreclaimable? no
lowmem_reserve[]: 0 0 748 748
Node 0 Normal free:123580kB min:1516kB low:1892kB high:2272kB
active:314180kB inactive:194732kB present:766464kB pages_scanned:0
all_unreclaimable? no
lowmem_reserve[]: 0 0 0 0
Node 0 DMA: 1*4kB 0*8kB 0*16kB 1*32kB 0*64kB 0*128kB 0*256kB 0*512kB
0*1024kB 0*2048kB 0*4096kB = 36kB
Node 0 DMA32: 4*4kB 3*8kB 2*16kB 3*32kB 4*64kB 5*128kB 3*256kB 5*512kB
4*1024kB 5*2048kB 776*4096kB = 3197224kB
Node 0 Normal: 14*4kB 14*8kB 8*16kB 6*32kB 1*64kB 3*128kB 3*256kB
2*512kB 4*1024kB 1*2048kB 28*4096kB = 123560kB
64847 total pagecache pages
0 pages in swap cache
Swap cache stats: add 0, delete 0, find 0/0
Free swap  = 502752kB
Total swap = 502752kB
1048576 pages RAM
52120 pages reserved
71967 pages shared
143004 pages non-shared

 --- [2]

BUG: unable to handle kernel NULL pointer dereference at 00000000000002c8
IP: [<ffffffff8046c84c>] map_single+0x1c/0x280
PGD 10e54e067 PUD 10e595067 PMD 0
Oops: 0000 [1] PREEMPT SMP DEBUG_PAGEALLOC
CPU 0
Modules linked in: kvm_intel kvm microcode uvcvideo compat_ioctl32
videodev v4l1_compat shpchp pci_hotplug
Pid: 5895, comm: skype Not tainted 2.6.27-rc6-235c-debug #1
RIP: 0010:[<ffffffff8046c84c>]  [<ffffffff8046c84c>] map_single+0x1c/0x280
RSP: 0018:ffff88010e78d988  EFLAGS: 00210296
RAX: 0000780000000000 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000005000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88010e78d9e8 R08: 0000000000000000 R09: 0000000000000001
R10: ffff88010e78d698 R11: 0000000000000001 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000005000 R15: ffff88012f1c9968
FS:  0000000000000000(0000) GS:ffffffff80a6cdc0(0063) knlGS:00000000f6355b90
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000000002c8 CR3: 000000010e57d000 CR4: 00000000000026e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process skype (pid: 5895, threadinfo ffff88010e78c000, task ffff88012b9cc460)
Stack:  0000000200000000 0000000000005000 0000000000000000 0000000000000000
 00000000000017b8 0000000000000000 ffff88010e78d9c8 0000000000000000
 0000000000000002 0000000000000000 0000000000005000 ffff88012f1c9968
Call Trace:
 [<ffffffff8046cbb0>] swiotlb_map_single_attrs+0x60/0xf0
 [<ffffffff8046cc4c>] swiotlb_map_single+0xc/0x10
 [<ffffffff8046cdee>] swiotlb_alloc_coherent+0xfe/0x180
 [<ffffffff80212731>] dma_alloc_coherent+0x281/0x310
 [<ffffffff805621c0>] hcd_buffer_alloc+0x50/0x90
 [<ffffffff805547fd>] usb_buffer_alloc+0x2d/0x40
 [<ffffffffa0056763>] uvc_alloc_urb_buffers+0x53/0xf0 [uvcvideo]
 [<ffffffffa0056958>] uvc_init_video+0x158/0x3e0 [uvcvideo]
 [<ffffffffa0056c17>] uvc_video_enable+0x37/0x80 [uvcvideo]
 [<ffffffffa0055853>] uvc_v4l2_do_ioctl+0x723/0x1260 [uvcvideo]
 [<ffffffff8026dd61>] ? trace_hardirqs_off_caller+0x21/0xc0
 [<ffffffff8026dd61>] ? trace_hardirqs_off_caller+0x21/0xc0
 [<ffffffffa0032c9f>] video_usercopy+0x19f/0x390 [videodev]
 [<ffffffffa0055130>] ? uvc_v4l2_do_ioctl+0x0/0x1260 [uvcvideo]
 [<ffffffff8026d0ce>] ? put_lock_stats+0xe/0x30
 [<ffffffffa0054dad>] uvc_v4l2_ioctl+0x4d/0x80 [uvcvideo]
 [<ffffffffa0045083>] native_ioctl+0x83/0x90 [compat_ioctl32]
 [<ffffffffa004534e>] v4l_compat_ioctl32+0x2be/0x1da4 [compat_ioctl32]
 [<ffffffff806aad21>] ? do_page_fault+0x3d1/0xae0
 [<ffffffff80270ccd>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff80270c59>] ? trace_hardirqs_on_caller+0x149/0x1b0
 [<ffffffff80270ccd>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff80329afa>] compat_sys_ioctl+0x8a/0x3c0
 [<ffffffff806a700d>] ? trace_hardirqs_off_thunk+0x3a/0x3c
 [<ffffffff8022f816>] sysenter_dispatch+0x7/0x2c
 [<ffffffff806a6fce>] ? trace_hardirqs_on_thunk+0x3a/0x3f

Code: 45 31 c0 48 89 e5 e8 a4 ff ff ff c9 c3 66 90 55 48 89 e5 41 57
41 56 41 55 41 54 53 48 83 ec 38 48 89 75 b0 48 89 55 a8 89 4d a4 <48>
8b 87 c8 02 00 00 48 85 c0 0f 84 1c 02 00 00 48 8b 58 08 48
RIP  [<ffffffff8046c84c>] map_single+0x1c/0x280
 RSP <ffff88010e78d988>
CR2: 00000000000002c8
---[ end trace 5d15baeeb7025a0e ]---

 --- [3]

ffffffff8046c830 <map_single>:
map_single():
/store/kernel/linux/lib/swiotlb.c:291
ffffffff8046c830:       55                      push   %rbp
ffffffff8046c831:       48 89 e5                mov    %rsp,%rbp
ffffffff8046c834:       41 57                   push   %r15
ffffffff8046c836:       41 56                   push   %r14
ffffffff8046c838:       41 55                   push   %r13
ffffffff8046c83a:       41 54                   push   %r12
ffffffff8046c83c:       53                      push   %rbx
ffffffff8046c83d:       48 83 ec 38             sub    $0x38,%rsp
ffffffff8046c841:       48 89 75 b0             mov    %rsi,-0x50(%rbp)
ffffffff8046c845:       48 89 55 a8             mov    %rdx,-0x58(%rbp)
ffffffff8046c849:       89 4d a4                mov    %ecx,-0x5c(%rbp)
dma_get_seg_boundary():
/store/kernel/linux/include/linux/dma-mapping.h:80
ffffffff8046c84c:       48 8b 87 c8 02 00 00    mov    0x2c8(%rdi),%rax <----

 --- [4]
Signed-off-by: NDaniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This adds is_swiotlb_buffer() helper function to see whether a buffer
belongs to the swiotlb buffer or not.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We don't need any check in swiotlb_unmap_single here. unmap_single is
appropriate.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We always need swiotlb memory here so address_needs_mapping and
swiotlb_force testings are irrelevant. map_single should be used here
instead of swiotlb_map_single.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The callers are supposed to set up the gfp flags appropriately.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: NJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>