Another design flaw in wireless extensions (is anybody
surprised?) in the way it handles the iw_encode_ext
structure: The structure is part of the 'extra' memory
but contains the key length explicitly, instead of it
just being the length of the extra buffer - size of
the struct and using the explicit key length only for
the get operation (which only writes it).
Therefore, we have this layout:
extra: +-------------------------+
| struct iw_encode_ext { |
| ... |
| u16 key_len; |
| u8 key[0]; |
| }; |
+-------------------------+
| key material |
+-------------------------+
Now, all drivers I checked use ext->key_len without
checking that both key_len and the struct fit into the
extra buffer that has been copied from userspace. This
leads to a buffer overrun while reading that buffer,
depending on the driver it may be possible to specify
arbitrary key_len or it may need to be a proper length
for the key algorithm specified.
Thankfully, this is only exploitable by root, but root
can actually cause a segfault or use kernel memory as
a key (which you can even get back with siocgiwencode
or siocgiwencodeext from the key buffer).
Fix this by verifying that key_len fits into the buffer
along with struct iw_encode_ext.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
AR5K_PHY_PLL_40MHZ_5413 should not be ORed with AR5K_PHY_MODE_RAD_RF5112
for 5 GHz channels.
The incorrect PLL value breaks scanning in the countries where 5 GHz
channels are allowed.
Signed-off-by: Pavel Roskin <proski@gnu.org>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The address range size calculation inside local_flush_tlb_kernel_range()
is being truncated by a too small size variable holder on 64-bit systems.
The truncated size can result in an erroneous tlbsize check that means we
sit spinning inside a loop trying to flush a hige number of TLB entries.
This is for all intents and purposes a system hang. Fix by using an
appropriately sized valiable to hold the size.
[Ralf: Greg's original patch submission identified the issue and fixed one
instance in tlb-r4k.c but there there were several more. For consistency
I also modified tlb-r3k.c even though that file is only used on 32-bit.]
Signed-off-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Richard Sandiford's new code for inserting the cache-barriers, for GCC
4.3 and above and already incorporated in the current GCC-release, uses
a slightly different option-syntax.
Signed-off-by: peter fuerst <post@pfrst.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The hang was caused by the use of disable_irq() from the interrupt handler
itself. Fixed by the use of disable_irq_nosync(). The issue was
triggered by:
commit 3aa551c9b4
Author: Thomas Gleixner <tglx@linutronix.de>
Date: Mon Mar 23 18:28:15 2009 +0100
genirq: add threaded interrupt handler support
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
The hang was caused by the use of disable_irq() from the interrupt handler
itself. Fixed by the use of disable_irq_nosync(). The issue was
triggered by:
commit 3aa551c9b4
Author: Thomas Gleixner <tglx@linutronix.de>
Date: Mon Mar 23 18:28:15 2009 +0100
genirq: add threaded interrupt handler support
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
cdrom: beyond ARRAY_SIZE of viocd_diskinfo
xen/blkfront: fix warning when deleting gendisk on unplug/shutdown
xen/blkfront: allow xenbus state transition to Closing->Closed when not Connected
The commit 5a641bcd63 changed the
printk format to '%lu', but the value passed seems to be dependent
on the architecture. On x86-64, I got a new warning now because an
int value is passed actaully.
As a workaround, just cast the value always to unsigned long.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
ipv4: make default for INET_LRO consistent with help text
net: fix skb_seq_read returning wrong offset/length for page frag data
pkt_sched: gen_estimator: use 64 bit intermediate counters for bps
be2net: add two new pci device ids to pci device table
sch_teql: should not dereference skb after ndo_start_xmit()
tcp: fix MSG_PEEK race check
Doc: fixed descriptions on /proc/sys/net/core/* and /proc/sys/net/unix/*
Neterion: *FIFO1_DMA_ERR set twice, should 2nd be *FIFO2_DMA_ERR?
mv643xx_eth: fix PPC DMA breakage
bonding: fix link down handling in 802.3ad mode
bridge: fix initial packet flood if !STP
bridge: relay bridge multicast pkgs if !STP
NET: Meth: Fix unsafe mix of irq and non-irq spinlocks.
mlx4_en: Fix not deleted napi structures
ipconfig: handle case of delayed DHCP server
netpoll: don't dereference NULL dev from np
wimax/i2400m: fix device crash: fix optimization in _roq_queue_update_ws
* 'core/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
futex: setup writeable mapping for futex ops which modify user space data
Currently, userspace can fail to obtain the SAREA mapping (among other
reasons) if it passes SAREA_MAX to drmAddMap without aligning it to the
page size. This breaks for example on PowerPC with 64K pages and radeon
despite the kernel radeon actually doing the right rouding in the first
place.
The way SAREA_MAX is defined with a bunch of ifdef's and duplicated
between libdrm and the X server is gross, ultimately it should be
retrieved by userspace from the kernel, but in the meantime, we have
plenty of existing userspace built with bad values that need to work.
This patch works around broken userspace by rounding the requested size
in drm_addmap_core() of any SHM map to the page size. Since the backing
memory for SHM maps is also allocated within addmap_core, there is no
danger of adjacent memory being exposed due to the increased map size.
The only side effect is that drivers that previously tried to create or
access SHM maps using a size < PAGE_SIZE and failed (getting -EINVAL),
will now succeed at the cost of a little bit more memory used if that
happens to be when the map is created.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
get_event_name uses sprintf to fill a buffer declared on the stack. It fills
the buffer 2 bytes at a time. What the code doesn't take into account is that
sprintf(buf, "%02x", data) actually writes 3 bytes. 2 bytes for the data and
then it nul terminates the string. Since we declare buf to be 40 characters
long and then we write 40 bytes of data into buf sprintf is going to write 41
characters. The fix is to leave room in buf for the nul terminator.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Recent PCI PM changes introduced a bug that causes some devices to be
mishandled after kexec and during early initialization. The failure
scenario in the kexec case is the following:
* Assume a PCI device is not power-manageable by the platform and has
PCI_PM_CTRL_NO_SOFT_RESET set in PMCSR.
* The device is put into D3 before kexec (using the native PCI PM).
* After kexec, pci_setup_device() sets the device's power state to
PCI_UNKNOWN.
* pci_set_power_state(dev, PCI_D0) is called by the device's driver.
* __pci_start_power_transition(dev, PCI_D0) is called and since the
device is not power-manageable by the platform, it causes
pci_update_current_state(dev, PCI_D0) to be called. As a result
the device's current_state field is updated to PCI_D3, in
accordance with the contents of its PCI PM registers.
* pci_raw_set_power_state() is called and it changes the device power
state to D0. *However*, it should also call pci_restore_bars() to
reinitialize the device, but it doesn't, because the device's
current_state field has been modified earlier.
To prevent this from happening, modify pci_platform_power_transition()
so that it doesn't use pci_update_current_state() to update the
current_state field for devices that aren't power-manageable by the
platform. Instead, this field should be updated directly for devices
that don't support the native PCI PM.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
The futex code installs a read only mapping via get_user_pages_fast()
even if the futex op function has to modify user space data. The
eventual fault was fixed up by futex_handle_fault() which walked the
VMA with mmap_sem held.
After the cleanup patches which removed the mmap_sem dependency of the
futex code commit 4dc5b7a36a49eff97050894cf1b3a9a02523717 (futex:
clean up fault logic) removed the private VMA walk logic from the
futex code. This change results in a stale RO mapping which is not
fixed up.
Instead of reintroducing the previous fault logic we set up the
mapping in get_user_pages_fast() read/write for all operations which
modify user space data. Also handle private futexes in the same way
and make the current unconditional access_ok(VERIFY_WRITE) depend on
the futex op.
Reported-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
CC: stable@kernel.org
Produce correct output for
- tagged commit (v2.6.30-rc6)
- past tagged commit (v2.6.30-rc5-299-g7c7327d)
- no tag
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Without this change Openmoko Freerunner (GTA02) bootstrap will deadlock.
As pointed out in other patches this issue is in the wild since the merge
of:
: commit 3aa551c9b4
: Author: Thomas Gleixner <tglx@linutronix.de>
: Date: Mon Mar 23 18:28:15 2009 +0100
:
: genirq: add threaded interrupt handler support
:
: Add support for threaded interrupt handlers
Signed-off-by: Nelson Castillo <arhuaco@freaks-unidos.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <balajirrao@openmoko.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Due to the way that the WM8350 audio driver handles CODEC_ENA many of
the WM8350 audio registers are marked as volatile when they aren't
actually so. Allow the audio driver to see a cache of these values for
inspection during interrupt context.
To do this we need to stop satisfying any bits from volatile registers
from cache - there's no real benefit from doing so anyway, we did the
read already.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
* 'fixes-for-linus' of git://git.monstr.eu/linux-2.6-microblaze:
microblaze: Fix kind-of-intr checking against number of interrupts
microblaze: Update Microblaze defconfig
Martin Knoblauch reports that trying to build 2.6.30-rc6-git3 with
RHEL4.3 userspace (gcc (GCC) 3.4.5 20051201 (Red Hat 3.4.5-2)) causes an
internal compiler error (ICE):
drivers/char/random.c: In function `get_random_int':
drivers/char/random.c:1672: error: unrecognizable insn:
(insn 202 148 150 0 /scratch/build/linux-2.6.30-rc6-git3/arch/x86/include/asm/tsc.h:23 (set (reg:SI 0 ax [91])
(subreg:SI (plus:DI (plus:DI (reg:DI 0 ax [88])
(subreg:DI (reg:SI 6 bp) 0))
(const_int -4 [0xfffffffffffffffc])) 0)) -1 (nil)
(nil))
drivers/char/random.c:1672: internal compiler error: in extract_insn, at recog.c:2083
and after some debugging it turns out that it's due to the code trying
to figure out the rough value of the current stack pointer by taking an
address of an uninitialized variable and casting that to an integer.
This is clearly a compiler bug, but it's not worth fighting - while the
current stack kernel pointer might be somewhat hard to predict in user
space, it's also not generally going to change for a lot of the call
chains for a particular process.
So just drop it, and mumble some incoherent curses at the compiler.
Tested-by: Martin Knoblauch <spamtrap@knobisoft.de>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For awhile now, many of the GEM code paths have allocated page or
object arrays with the slab allocator. This is nice and fast, but
won't work well if memory is fragmented, since the slab allocator works
with physically contiguous memory (i.e. order > 2 allocations are
likely to fail fairly early after booting and doing some work).
This patch works around the issue by falling back to vmalloc for
>PAGE_SIZE allocations. This is ugly, but much less work than chaining
a bunch of pages together by hand (suprisingly there's not a bunch of
generic kernel helpers for this yet afaik). vmalloc space is somewhat
precious on 32 bit kernels, but our allocations shouldn't be big enough
to cause problems, though they're routinely more than a page.
Note that this patch doesn't address the unchecked
alloc-based-on-ioctl-args in GEM; that needs to be fixed in a separate
patch.
Also, I've deliberately ignored the DRM's "area" junk. I don't think
anyone actually uses it anymore and I'm hoping it gets ripped out soon.
[Updated: removed size arg to new free function. We could unify the
free functions as well once the DRM mem tracking is ripped out.]
fd.o bug #20152 (part 1/3)
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
This is the third respin of the patch posted yesterday to fix the error
handling in cifs_follow_symlink. It also includes a fix for a bogus NULL
pointer check in CIFSSMBQueryUnixSymLink that Jeff Moyer spotted.
It's possible for CIFSSMBQueryUnixSymLink to return without setting
target_path to a valid pointer. If that happens then the current value
to which we're initializing this pointer could cause an oops when it's
kfree'd.
This patch is a little more comprehensive than the last patches. It
reorganizes cifs_follow_link a bit for (hopefully) better readability.
It should also eliminate the uneeded allocation of full_path on servers
without unix extensions (assuming they can get to this point anyway, of
which I'm not convinced).
On a side note, I'm not sure I agree with the logic of enabling this
query even when unix extensions are disabled on the client. It seems
like that should disable this as well. But, changing that is outside the
scope of this fix, so I've left it alone for now.
Reported-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Christoph Hellwig <hch@inraded.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Currently blkfront gives a warning when hot unplugging due to calling
del_gendisk() with interrupts disabled (due to blkif_io_lock).
WARNING: at kernel/softirq.c:124 local_bh_enable+0x36/0x84()
Modules linked in: xenfs xen_netfront ext3 jbd mbcache xen_blkfront
Pid: 13, comm: xenwatch Not tainted 2.6.29-xs5.5.0.13 #3
Call Trace:
[<c012611c>] warn_slowpath+0x80/0xb6
[<c0104cf1>] xen_sched_clock+0x16/0x63
[<c0104710>] xen_force_evtchn_callback+0xc/0x10
[<c0104e32>] check_events+0x8/0xe
[<c0104d9b>] xen_restore_fl_direct_end+0x0/0x1
[<c0103749>] xen_mc_flush+0x10a/0x13f
[<c0105bd2>] __switch_to+0x114/0x14e
[<c011d92b>] dequeue_task+0x62/0x70
[<c0123b6f>] finish_task_switch+0x2b/0x84
[<c0299877>] schedule+0x66d/0x6e7
[<c0104710>] xen_force_evtchn_callback+0xc/0x10
[<c0104710>] xen_force_evtchn_callback+0xc/0x10
[<c012a642>] local_bh_enable+0x36/0x84
[<c022f9a7>] sk_filter+0x57/0x5c
[<c0233dae>] netlink_broadcast+0x1d5/0x315
[<c01c6371>] kobject_uevent_env+0x28d/0x331
[<c01e7ead>] device_del+0x10f/0x120
[<c01e7ec6>] device_unregister+0x8/0x10
[<c015f86d>] bdi_unregister+0x2d/0x39
[<c01bf6f4>] unlink_gendisk+0x23/0x3e
[<c01ac946>] del_gendisk+0x7b/0xe7
[<d0828c19>] blkfront_closing+0x28/0x6e [xen_blkfront]
[<d082900c>] backend_changed+0x3ad/0x41d [xen_blkfront]
We can fix this by calling del_gendisk() later in blkfront_closing, after
releasing blkif_io_lock. Since the queue is stopped during the interrupts
disabled phase I don't think there is any danger of an event occuring between
releasing the blkif_io_lock and deleting the disk.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This situation can occur when attempting to attach a block device whose
backend is an empty physical CD-ROM driver. The backend in this case
will go directly from the Initialising state to Closing->Closed.
Previously this would result in a NULL pointer deref on info->gd
(xenbus_dev_fatal does not return as a1a15ac5 seems to expect)
Cc: stable@kernel.org
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Commit e81963b1 ("ipv4: Make INET_LRO a bool instead of tristate.")
changed this config from tristate to bool. Add default so that it is
consistent with the help text.
Signed-off-by: Frans Pop <elendil@planet.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>
When called with a consumed value that is less than skb_headlen(skb)
bytes into a page frag, skb_seq_read() incorrectly returns an
offset/length relative to skb->data. Ensure that data which should come
from a page frag does.
Signed-off-by: Thomas Chenault <thomas_chenault@dell.com>
Tested-by: Shyam Iyer <shyam_iyer@dell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The problem is that permission checking is skipped if atomic open is
possible, but when exec opens a file, it just opens it O_READONLY which
means EXEC permission will not be checked at that time.
This problem is observed by the following sequence (executed as root):
mount -t nfs4 server:/ /mnt4
echo "ls" >/mnt4/foo
chmod 744 /mnt4/foo
su guest -c "mnt4/foo"
Signed-off-by: Frank Filz <ffilzlnx@us.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
Tested-by: Eugene Teo <eugeneteo@kernel.sg>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
gen_estimator can overflow bps (bytes per second) with Gb links, while
it was designed with a u32 API, with a theorical limit of 34360Mbit
(2^32 bytes)
Using 64 bit intermediate avbps/brate counters can allow us to reach
this theorical limit.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It is illegal to dereference a skb after a successful ndo_start_xmit()
call. We must store skb length in a local variable instead.
Bug was introduced in 2.6.27 by commit 0abf77e55a
(net_sched: Add accessor function for packet length for qdiscs)
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 518a09ef11 (tcp: Fix recvmsg MSG_PEEK influence of
blocking behavior) lets the loop run longer than the race check
did previously expect, so we need to be more careful with this
check and consider the work we have been doing.
I tried my best to deal with urg hole madness too which happens
here:
if (!sock_flag(sk, SOCK_URGINLINE)) {
++*seq;
...
by using additional offset by one but I certainly have very
little interest in testing that part.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Tested-by: Frans Pop <elendil@planet.nl>
Tested-by: Ian Zimmermann <itz@buug.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
In Commit
commit 3b8b5c9b1f
Author: Eric Moore <eric.moore@lsi.com>
Date: Tue Apr 21 15:44:27 2009 -0600
[SCSI] mpt2sas : bump driver version to 01.100.02.00
The MPT2SAS_MAJOR_VERSION didn't get bumped from 00 to 01 so
applications will see it incorrectly as 00.100.02.00 driver instead of
01.100.02.00. Fix by making MPT2SAS_MAJOR_VERSION match the major
number in MPT2SAS_DRIVER_VERSION
Signed-off-by: Eric Moore <eric.moore@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc: Explicit alignment for .data.cacheline_aligned
powerpc/ps3: Update ps3_defconfig
powerpc/ftrace: Fix constraint to be early clobber
powerpc/ftrace: Use pr_devel() in ftrace.c
powerpc: Do not assert pte_locked for hugepage PTE entries
* 'sched-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: Fix fallback sched_clock()'s offset when using jiffies
* 'core-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
lockdep: increase MAX_LOCKDEP_ENTRIES and MAX_LOCKDEP_CHAINS
Remove the __initdata annotation for the clock lookups, since they
will be needed when loading modules which use clk_get().
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Remove the __initdata annotation for the clock lookups, since they
will be needed when loading modules which use clk_get().
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
tracing: Append prompt in /debug/tracing/README file
x86/function-graph: fix constraint for recording old return value
Commit c45d6320 ("fix reference counting of ftdi_private") stopped
ftdi_sio_port_remove() from directly freeing the port-private data, with
the intention if the port was still open, it would be freed when
ftdi_close() is eventually called and releases the last refcount on the
structure.
That's all very well, but ftdi_sio_port_remove() still contains a call
to usb_set_serial_port_data(port, NULL) -- so by the time we get to
ftdi_close() for the port which was unplugged, it _still_ oopses on
dereferencing that NULL pointer, as it did before (and does in 2.6.29).
The fix is just not to clear the private data in ftdi_sio_port_remove().
Then the refcount is properly reduced to zero when the final kref_put()
happens in ftdi_close().
Remove a bogus comment too, while we're at it. And stop doing things
inside "if (priv)" -- it must _always_ be there.
Based loosely on an earlier patch by Daniel Mack, and suggestions by
Alan Stern.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Tested-by: Daniel Mack <daniel@caiaq.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 5b7f3a50 (fix dataflash 64-bit divisions) unfortunately
introduced a typo. Erase addr and len were swapped in the pageaddr
calculation, causing the wrong sectors to get erased.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
`local_add_unless(x, y, z)' will be expanded to `(&(x)->y, (y), (x))', but
`&(x)->y' should be `&(x)->a'
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
pfn_valid() is meant to be able to tell if a given PFN has valid memmap
associated with it or not. In FLATMEM, it is expected that holes always
have valid memmap as long as there is valid PFNs either side of the hole.
In SPARSEMEM, it is assumed that a valid section has a memmap for the
entire section.
However, ARM and maybe other embedded architectures in the future free
memmap backing holes to save memory on the assumption the memmap is never
used. The page_zone linkages are then broken even though pfn_valid()
returns true. A walker of the full memmap must then do this additional
check to ensure the memmap they are looking at is sane by making sure the
zone and PFN linkages are still valid. This is expensive, but walkers of
the full memmap are extremely rare.
This was caught before for FLATMEM and hacked around but it hits again for
SPARSEMEM because the page_zone linkages can look ok where the PFN linkages
are totally screwed. This looks like a hatchet job but the reality is that
any clean solution would end up consumning all the memory saved by punching
these unexpected holes in the memmap. For example, we tried marking the
memmap within the section invalid but the section size exceeds the size of
the hole in most cases so pfn_valid() starts returning false where valid
memmap exists. Shrinking the size of the section would increase memory
consumption offsetting the gains.
This patch identifies when an architecture is punching unexpected holes
in the memmap that the memory model cannot automatically detect and sets
ARCH_HAS_HOLES_MEMORYMODEL. At the moment, this is restricted to EP93xx
which is the model sub-architecture this has been reported on but may expand
later. When set, walkers of the full memmap must call memmap_valid_within()
for each PFN and passing in what it expects the page and zone to be for
that PFN. If it finds the linkages to be broken, it assumes the memmap is
invalid for that PFN.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The remove function uses __devexit, so the .remove assignment needs
__devexit_p() to fix a build error with hotplug disabled.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
CC: Liam Girdwood <lrg@slimlogic.co.uk>
CC: Mike Rapoport <mike@compulab.co.il>
CC: Eric Miao <eric.miao@marvell.com>
Acked-by: Eric Miao <eric.y.miao@gmail.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
