This code elsewhere returns a negative constant to an indicate an error,
while IS_ERR returns the result of a >= operation.
The semantic patch that fixes this problem is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
expression x;
@@
if (...) { ...
- return IS_ERR(x);
+ return PTR_ERR(x);
}
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Commit 8419fdbaf2
(omap2+: Add omap_mux_get_by_name) introduced the following
compile warning:
arch/arm/mach-omap2/mux.c: In function '_omap_mux_get_by_name':
arch/arm/mach-omap2/mux.c:163:17: warning: 'found_mode' may be used
uninitialized in this function
Signed-off-by: Felipe Balbi <balbi@ti.com>
[tony@atomide.com: updated comments]
Signed-off-by: Tony Lindgren <tony@atomide.com>
Commit 03a9e51261
(omap1: Use asm_irq_flags for entry-macro.S) added support
for multi-omap builds with addition of the omap_irq_flags.
Commit 9f9605c2ed
(omap2+: Fix unused variable warning for omap_irq_base)
simplified omap2+ entry-macro.S by moving omap_irq_flags
out of entry-macro.S.
Simplify omap1 entry-macro.S in a similar way to keep the
code consistent. Based on a similar earlier patch for omap2+
by Russell King <rmk+kernel@arm.linux.org.uk>.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Commit 5d190c4010
(omap2+: Initialize omap_irq_base for entry-macro.S from
platform code) simplified the handling of omap_irq_base
for multi-omap builds. However, this patch also introduced
a build warning for !MULTI_OMAP2 builds:
arch/arm/mach-omap2/io.c: In function 'omap_irq_base_init':
arch/arm/mach-omap2/io.c:322: warning: unused variable 'omap_irq_base'
Fix this by removing the ifdef. Also simplify things further
by moving omap_irq_base out of entry-macro.S.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[tony@atomide.com: updated comments]
Signed-off-by: Tony Lindgren <tony@atomide.com>
The MMCIDATACNT register contain the number of byte left at error
not the number of words, so loose the << 2 thing. Further if CRC
fails on the first block, we may end up with a negative number
of transferred bytes which is not good, and the formula was in
wrong order.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
percpu, x86: Fix percpu_xchg_op()
x86: Remove left over system_64.h
x86-64: Don't use pointer to out-of-scope variable in dump_trace()
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (43 commits)
bnx2: Eliminate AER error messages on systems not supporting it
cnic: Fix big endian bug
xfrm6: Don't forget to propagate peer into ipsec route.
tg3: Use new VLAN code
bonding: update documentation - alternate configuration.
TCP: fix a bug that triggers large number of TCP RST by mistake
MAINTAINERS: remove Reinette Chatre as iwlwifi maintainer
rt2x00: add device id for windy31 usb device
mac80211: fix a crash in ieee80211_beacon_get_tim on change_interface
ipv6: Revert 'administrative down' address handling changes.
textsearch: doc - fix spelling in lib/textsearch.c.
USB NET KL5KUSB101: Fix mem leak in error path of kaweth_download_firmware()
pch_gbe: don't use flush_scheduled_work()
bnx2: Always set ETH_FLAG_TXVLAN
net: clear heap allocation for ethtool_get_regs()
ipv6: Always clone offlink routes.
dcbnl: make get_app handling symmetric for IEEE and CEE DCBx
tcp: fix bug in listening_get_next()
inetpeer: Use correct AVL tree base pointer in inet_getpeer().
GRO: fix merging a paged skb after non-paged skbs
...
Replaced md4 hashing function local to cifs module with kernel crypto APIs.
As a result, md4 hashing function and its supporting functions in
file md4.c are not needed anymore.
Cleaned up function declarations, removed forward function declarations,
and removed a header file that is being deleted from being included.
Verified that sec=ntlm/i, sec=ntlmv2/i, and sec=ntlmssp/i work correctly.
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
This patch adds __GFP_NORETRY and __GFP_NOMEMALLOC flags to the kmemleak
metadata allocations so that it has a smaller effect on the users of the
kernel slab allocator. Since kmemleak allocations can now fail more
often, this patch also reduces the verbosity by passing __GFP_NOWARN and
not dumping the stack trace when a kmemleak allocation fails.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Ted Ts'o <tytso@mit.edu>
We don't need to memset if we just use kzalloc() rather than kmalloc() in
kmemleak_test_init().
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
With this patch, the cpuidle driver does not load and
does not issue the mwait operations. Instead the hypervisor
is doing them (b/c we call the safe_halt pvops call).
This fixes quite a lot of bootup issues wherein the user had
to force interrupts for the continuation of the bootup.
Details are discussed in:
http://lists.xensource.com/archives/html/xen-devel/2011-01/msg00535.html
[v2: Wrote the commit description]
Reported-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Tested-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Under Dell Inspiron 1525, and Intel SandyBridge SDP's the
BIOS e820 RAM is not page-aligned:
[ 0.000000] Xen: 0000000000100000 - 00000000df66d800 (usable)
We were not handling that and ended up setting up a pagetable
that included up to df66e000 with the disastrous effect that when
memset(NODE_DATA(nodeid), 0, sizeof(pg_data_t));
tried to clear the page it would crash at the 2K mark.
Initially reported by Michael Young @
http://lists.xensource.com/archives/html/xen-devel/2011-01/msg00108.html
The fix is to page-align the size and also take into consideration
the start of the E820 (in case that is not page-aligned either). This
fixes the bootup failure on those affected machines.
This patch is a rework of the Micheal A Young initial patch and
considers the case if the start is not page-aligned.
Reported-by: Michael A Young <m.a.young@durham.ac.uk>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Michael A Young <m.a.young@durham.ac.uk>
In case the mfn_list does not have enough entries to fill
a p2m page we do not want the entries from max_pfn up to
the boundary to be filled with unknown values. Hence
set them to INVALID_P2M_ENTRY.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
A future patch will export gic_mask_irq and gic_unmask_irq.
Rename the pointers in arch/arm/mach-tegra/irq.c to avoid
a compile error.
Signed-off-by: Colin Cross <ccross@android.com>
Commit 37337a8d5e, "ARM: tegra: irq_data
conversion." missed changing one reference to 'irq' in the function
tegra_gpio_irq_set_type(). This patch fixes the build error.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Lennert Buytenhek <buytenh@secretlab.ca>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Colin Cross <ccross@android.com>
R6xx+ have per-block swappers. BE content in the
framebuffer will now be swapped properly during scanout.
Untested, however, the same code is reported working in
the UMS ddx.
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>
Force DVI mode if the user specifies radeon.audio=0. The driver
doesn't handle HDMI mode properly in some cases.
Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=27731
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>
Check if there is a big enough dp clock & enough dp lane to
drive the video mode provided.
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-By: Alex Deucher <alexdeucher@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Dave Airlie <airlied@gmail.com>
On PPC for example, AER is not supported and we see unnecessary AER
error message without this patch:
bnx2 0003:01:00.1: pci_cleanup_aer_uncorrect_error_status failed 0xfffffffb
Reported-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The chip's page tables did not set up properly on big endian machines,
causing EEH errors on PPC machines.
Reported-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Like ipv4, we have to propagate the ipv6 route peer into
the ipsec top-level route during instantiation.
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch pivots the tg3 driver to the new VLAN infrastructure.
All references to vlgrp have been removed. The driver still attempts to
disable VLAN tag stripping if CONFIG_VLAN_8021Q or
CONFIG_VLAN_8021Q_MODULE is not defined.
Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
BugLink: http://bugs.launchpad.net/bugs/707902
More Thinkpad machines with invalid SKU found, that disables
automute between speakers and headphones on these machines.
Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This patch adds the linux/mm.h header file to the AVR32 arch pgalloc.c
implementation to fix the undefined reference to pgtable_page_ctor() and
pgtable_page_dtor().
Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
The delta in clock_task is a more fair attribution of how much time a tg has
been contributing load to the current cpu.
While not really important it also means we're more in sync (by magnitude)
with respect to periodic updates (since __update_curr deltas are clock_task
based).
Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20110122044852.007092349@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since updates are against an entity's queuing cfs_rq it's not possible to
enter update_cfs_{shares,load} with a NULL cfs_rq. (Indeed, update_cfs_load
would crash prior to the check if we did anyway since we load is examined
during the initializers).
Also, in the update_cfs_load case there's no point
in maintaining averages for rq->cfs_rq since we don't perform shares
distribution at that level -- NULL check is replaced accordingly.
Thanks to Dan Carpenter for pointing out the deference before NULL check.
Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20110122044851.825284940@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
While care is taken around the zero-point in effective_load to not exceed
the instantaneous rq->weight, it's still possible (e.g. using wake_idx != 0)
for (load + effective_load) to underflow.
In this case the comparing the unsigned values can result in incorrect balanced
decisions.
Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20110122044851.734245014@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'drm-nouveau-next' of git://git.freedesktop.org/git/nouveau/linux-2.6:
drm/nvc0/grctx: correct an off-by-one
drm/nv50: Fix race with PFIFO during PGRAPH context destruction.
drm/nouveau: Workaround incorrect DCB entry on a GeForce3 Ti 200.
drm/nvc0: implement irq handler for whatever's at 0x14xxxx
drm/nvc0: fix incorrect TPC register setup
drm/nouveau: probe for adt7473 before f75375
drm/nouveau: remove dead function definition
These recent percpu commits:
2485b6464c: x86,percpu: Move out of place 64 bit ops into X86_64 section
8270137a0d: cpuops: Use cmpxchg for xchg to avoid lock semantics
Caused this 'perf top' crash:
Kernel panic - not syncing: Fatal exception in interrupt
Pid: 0, comm: swapper Tainted: G D
2.6.38-rc2-00181-gef71723 #413 Call Trace: <IRQ> [<ffffffff810465b5>]
? panic
? kmsg_dump
? kmsg_dump
? oops_end
? no_context
? __bad_area_nosemaphore
? perf_output_begin
? bad_area_nosemaphore
? do_page_fault
? __task_pid_nr_ns
? perf_event_tid
? __perf_event_header__init_id
? validate_chain
? perf_output_sample
? trace_hardirqs_off
? page_fault
? irq_work_run
? update_process_times
? tick_sched_timer
? tick_sched_timer
? __run_hrtimer
? hrtimer_interrupt
? account_system_vtime
? smp_apic_timer_interrupt
? apic_timer_interrupt
...
Looking at assembly code, I found:
list = this_cpu_xchg(irq_work_list, NULL);
gives this wrong code : (gcc-4.1.2 cross compiler)
ffffffff810bc45e:
mov %gs:0xead0,%rax
cmpxchg %rax,%gs:0xead0
jne ffffffff810bc45e <irq_work_run+0x3e>
test %rax,%rax
je ffffffff810bc4aa <irq_work_run+0x8a>
Tell gcc we dirty eax/rax register in percpu_xchg_op()
Compiler must use another register to store pxo_new__
We also dont need to reload percpu value after a jump,
since a 'failed' cmpxchg already updated eax/rax
Wrong generated code was :
xor %rax,%rax /* load 0 into %rax */
1: mov %gs:0xead0,%rax
cmpxchg %rax,%gs:0xead0
jne 1b
test %rax,%rax
After patch :
xor %rdx,%rdx /* load 0 into %rdx */
mov %gs:0xead0,%rax
1: cmpxchg %rdx,%gs:0xead0
jne 1b:
test %rax,%rax
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
LKML-Reference: <1295973114.3588.312.camel@edumazet-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Left-over from the x86 merge ...
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4D3E23D1.7010405@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: wacom - pass touch resolution to clients through input_absinfo
Input: wacom - add 2 Bamboo Pen and touch models
Input: sysrq - ensure sysrq_enabled and __sysrq_enabled are consistent
Input: sparse-keymap - fix KEY_VSW handling in sparse_keymap_setup
Input: tegra-kbc - add tegra keyboard driver
Input: gpio_keys - switch to using request_any_context_irq
Input: serio - allow registered drivers to get status flag
Input: ct82710c - return proper error code for ct82c710_open
Input: bu21013_ts - added regulator support
Input: bu21013_ts - remove duplicate resolution parameters
Input: tnetv107x-ts - don't treat NULL clk as an error
Input: tnetv107x-keypad - don't treat NULL clk as an error
Fix up trivial conflicts in drivers/input/keyboard/Makefile due to
additions of tc3589x/Tegra drivers
The bfin_sdh driver allocates the wrong size for the private data
in the mmc_host. The first parameter of mmc_alloc_host should be
the size of the local driver struct rather than the common mmc_host.
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: <stable@kernel.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
We have 8-bit width support but is not a v3 controller.
So we need platform_8bit_width() to support 8-bit buswidth.
Also we need MMC_CAP_8_BIT_DATA, so we add it in platdata.
This gets 8-bit support working again on s3c, after we previously
disabled 8-bit by default on non-v3 controllers.
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
As stated in section 2.4 of RFC 5661, subsequent instances of the client need
to present the same co_ownerid. Concatinate the client's IP dot address,
host name, and the rpc_auth pseudoflavor to form the co_ownerid.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
clk_get() returns a struct clk cookie to the driver and some platforms
may return NULL if they only support a single clock. clk_get() has only
failed if it returns a ERR_PTR() encoded pointer.
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
Don't read the command response from the registers when either the
command timed out (because there was no response from the card) or
the checksum on the response was invalid.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Chris Ball <cjb@laptop.org>
Including usb.h once is enough in drivers/mmc/host/ushc.c
This removes the duplicate.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Chris Ball <cjb@laptop.org>
Also remove fake ABS_RX/ABS_RY "axes" that were used to report physical
dimensions now that we have better way.
Signed-off-by: Ping Cheng <pingc@wacom.com>
Reviewed-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
The -rt patches change the console_semaphore to console_mutex. As a
result, a quite large chunk of the patches changes all
acquire/release_console_sem() to acquire/release_console_mutex()
This commit makes things use more neutral function names which dont make
implications about the underlying lock.
The only real change is the return value of console_trylock which is
inverted from try_acquire_console_sem()
This patch also paves the way to switching console_sem from a semaphore to
a mutex.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: make console_trylock return 1 on success, per Geert]
Signed-off-by: Torben Hohn <torbenh@gmx.de>
Cc: Thomas Gleixner <tglx@tglx.de>
Cc: Greg KH <gregkh@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix potential use of uninitialised variable caused by recent
decompressor code optimisations.
In zlib_uncompress (zlib_wrapper.c) we have
int zlib_err, zlib_init = 0;
...
do {
...
if (avail == 0) {
offset = 0;
put_bh(bh[k++]);
continue;
}
...
zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
...
} while (zlib_err == Z_OK);
If continue is executed (avail == 0) then the while condition will be
evaluated testing zlib_err, which is uninitialised first time around the
loop.
Fix this by getting rid of the 'if (avail == 0)' condition test, this
edge condition should not be being handled in the decompressor code, and
instead handle it generically in the caller code.
Similarly for xz_wrapper.c.
Incidentally, on most architectures (bar Mips and Parisc), no
uninitialised variable warning is generated by gcc, this is because the
while condition test on continue is optimised out and not performed
(when executing continue zlib_err has not been changed since entering
the loop, and logically if the while condition was true previously, then
it's still true).
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
Reported-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Executed command: fsstress -d /mnt -n 600 -p 850
crash> bt
PID: 7947 TASK: ffff880160546a70 CPU: 0 COMMAND: "fsstress"
#0 [ffff8800dfc07d00] machine_kexec at ffffffff81030db9
#1 [ffff8800dfc07d70] crash_kexec at ffffffff810a7952
#2 [ffff8800dfc07e40] oops_end at ffffffff814aa7c8
#3 [ffff8800dfc07e70] die_nmi at ffffffff814aa969
#4 [ffff8800dfc07ea0] do_nmi_callback at ffffffff8102b07b
#5 [ffff8800dfc07f10] do_nmi at ffffffff814aa514
#6 [ffff8800dfc07f50] nmi at ffffffff814a9d60
[exception RIP: __lookup_tag+100]
RIP: ffffffff812274b4 RSP: ffff88016056b998 RFLAGS: 00000287
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000006
RDX: 000000000000001d RSI: ffff88016056bb18 RDI: ffff8800c85366e0
RBP: ffff88016056b9c8 R8: ffff88016056b9e8 R9: 0000000000000000
R10: 000000000000000e R11: ffff8800c8536908 R12: 0000000000000010
R13: 0000000000000040 R14: ffffffffffffffc0 R15: ffff8800c85366e0
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
<NMI exception stack>
#7 [ffff88016056b998] __lookup_tag at ffffffff812274b4
#8 [ffff88016056b9d0] radix_tree_gang_lookup_tag_slot at ffffffff81227605
#9 [ffff88016056ba20] find_get_pages_tag at ffffffff810fc110
#10 [ffff88016056ba80] pagevec_lookup_tag at ffffffff81105e85
#11 [ffff88016056baa0] write_cache_pages at ffffffff81104c47
#12 [ffff88016056bbd0] generic_writepages at ffffffff81105014
#13 [ffff88016056bbe0] do_writepages at ffffffff81105055
#14 [ffff88016056bbf0] __filemap_fdatawrite_range at ffffffff810fb2cb
#15 [ffff88016056bc40] filemap_write_and_wait_range at ffffffff810fb32a
#16 [ffff88016056bc70] generic_file_direct_write at ffffffff810fb3dc
#17 [ffff88016056bce0] __generic_file_aio_write at ffffffff810fcee5
#18 [ffff88016056bda0] generic_file_aio_write at ffffffff810fd085
#19 [ffff88016056bdf0] do_sync_write at ffffffff8114f9ea
#20 [ffff88016056bf00] vfs_write at ffffffff8114fcf8
#21 [ffff88016056bf30] sys_write at ffffffff81150691
#22 [ffff88016056bf80] system_call_fastpath at ffffffff8100c0b2
I think this root cause is the following:
radix_tree_range_tag_if_tagged() always tags the root tag with settag
if the root tag is set with iftag even if there are no iftag tags
in the specified range (Of course, there are some iftag tags
outside the specified range).
===============================================================================
[[[Detailed description]]]
(1) Why cannot radix_tree_gang_lookup_tag_slot() return forever?
__lookup_tag():
- Return with 0.
- Return with the index which is not bigger than the old one as the
input parameter.
Therefore the following "while" repeats forever because the above
conditions cause "ret" not to be updated and the cur_index cannot be
changed into the bigger one.
(So, radix_tree_gang_lookup_tag_slot() cannot return forever.)
radix_tree_gang_lookup_tag_slot():
1178 while (ret < max_items) {
1179 unsigned int slots_found;
1180 unsigned long next_index; /* Index of next search */
1181
1182 if (cur_index > max_index)
1183 break;
1184 slots_found = __lookup_tag(node, results + ret,
1185 cur_index, max_items - ret, &next_index,
tag);
1186 ret += slots_found;
// cannot update ret because slots_found == 0.
// so, this while loops forever.
1187 if (next_index == 0)
1188 break;
1189 cur_index = next_index;
1190 }
(2) Why does __lookup_tag() return with 0 and doesn't update the index?
Assuming the following:
- the one of the slot in radix_tree_node is NULL.
- the one of the tag which corresponds to the slot sets with
PAGECACHE_TAG_TOWRITE or other.
- In a certain height(!=0), the corresponding index is 0.
a) __lookup_tag() notices that the tag is set.
1005 static unsigned int
1006 __lookup_tag(struct radix_tree_node *slot, void ***results, unsigned long index,
1007 unsigned int max_items, unsigned long *next_index, unsigned int tag)
1008 {
1009 unsigned int nr_found = 0;
1010 unsigned int shift, height;
1011
1012 height = slot->height;
1013 if (height == 0)
1014 goto out;
1015 shift = (height-1) * RADIX_TREE_MAP_SHIFT;
1016
1017 while (height > 0) {
1018 unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ;
1019
1020 for (;;) {
1021 if (tag_get(slot, tag, i))
1022 break;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* the index is not updated yet.
b) __lookup_tag() notices that the slot is NULL.
1023 index &= ~((1UL << shift) - 1);
1024 index += 1UL << shift;
1025 if (index == 0)
1026 goto out; /* 32-bit wraparound */
1027 i++;
1028 if (i == RADIX_TREE_MAP_SIZE)
1029 goto out;
1030 }
1031 height--;
1032 if (height == 0) { /* Bottom level: grab some items */
...
1055 }
1056 shift -= RADIX_TREE_MAP_SHIFT;
1057 slot = rcu_dereference_raw(slot->slots[i]);
1058 if (slot == NULL)
1059 break;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
c) __lookup_tag() doesn't update the index and return with 0.
1060 }
1061 out:
1062 *next_index = index;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1063 return nr_found;
1064 }
(3) Why is the slot NULL even if the tag is set?
Because radix_tree_range_tag_if_tagged() always sets the root tag with
PAGECACHE_TAG_TOWRITE if the root tag is set with PAGECACHE_TAG_DIRTY,
even if there is no tag which can be set with PAGECACHE_TAG_TOWRITE
in the specified range (from *first_indexp to last_index). Of course,
some PAGECACHE_TAG_DIRTY nodes must exist outside the specified range.
(radix_tree_range_tag_if_tagged() is called only from tag_pages_for_writeback())
640 unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root
*root,
641 unsigned long *first_indexp, unsigned long last_index,
642 unsigned long nr_to_tag,
643 unsigned int iftag, unsigned int settag)
644 {
645 unsigned int height = root->height;
646 struct radix_tree_path path[height];
647 struct radix_tree_path *pathp = path;
648 struct radix_tree_node *slot;
649 unsigned int shift;
650 unsigned long tagged = 0;
651 unsigned long index = *first_indexp;
652
653 last_index = min(last_index, radix_tree_maxindex(height));
654 if (index > last_index)
655 return 0;
656 if (!nr_to_tag)
657 return 0;
658 if (!root_tag_get(root, iftag)) {
659 *first_indexp = last_index + 1;
660 return 0;
661 }
662 if (height == 0) {
663 *first_indexp = last_index + 1;
664 root_tag_set(root, settag);
665 return 1;
666 }
...
733 root_tag_set(root, settag);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
734 *first_indexp = index;
735
736 return tagged;
737 }
As the result, there is no radix_tree_node which is set with
PAGECACHE_TAG_TOWRITE but the root tag(radix_tree_root) is set with
PAGECACHE_TAG_TOWRITE.
[figure: inside radix_tree]
(Please see the figure with typewriter font)
===========================================
[roottag = DIRTY]
| tag=0:NOTHING
tag[0 0 0 1] 1:DIRTY
[x x x +] 2:WRITEBACK
| 3:DIRTY,WRITEBACK
p 4:TOWRITE
<---> 5:DIRTY,TOWRITE ...
specified range (index: 0 to 2)
* There is no DIRTY tag within the specified range.
(But there is a DIRTY tag outside that range.)
| | | | | | | | |
after calling tag_pages_for_writeback()
| | | | | | | | |
v v v v v v v v v
[roottag = DIRTY,TOWRITE]
| p is "page".
tag[0 0 0 1] x is NULL.
[x x x +] +- is a pointer to "page".
|
p
* But TOWRITE tag is set on the root tag.
============================================
After that, radix_tree_extend() via radix_tree_insert() is called
when the page is added.
This function sets the new radix_tree_node with PAGECACHE_TAG_TOWRITE
to succeed the status of the root tag.
246 static int radix_tree_extend(struct radix_tree_root *root, unsigned long
index)
247 {
248 struct radix_tree_node *node;
249 unsigned int height;
250 int tag;
251
252 /* Figure out what the height should be. */
253 height = root->height + 1;
254 while (index > radix_tree_maxindex(height))
255 height++;
256
257 if (root->rnode == NULL) {
258 root->height = height;
259 goto out;
260 }
261
262 do {
263 unsigned int newheight;
264 if (!(node = radix_tree_node_alloc(root)))
265 return -ENOMEM;
266
267 /* Increase the height. */
268 node->slots[0] = radix_tree_indirect_to_ptr(root->rnode);
269
270 /* Propagate the aggregated tag info into the new root */
271 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
272 if (root_tag_get(root, tag))
273 tag_set(node, tag, 0);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
274 }
===========================================
[roottag = DIRTY,TOWRITE]
| :
tag[0 0 0 1] [0 0 0 0]
[x x x +] [+ x x x]
| |
p p (new page)
| | | | | | | | |
after calling radix_tree_insert
| | | | | | | | |
v v v v v v v v v
[roottag = DIRTY,TOWRITE]
|
tag [5 0 0 0] * DIRTY and TOWRITE tags are
[+ + x x] succeeded to the new node.
| |
tag [0 0 0 1] [0 0 0 0]
[x x x +] [+ x x x]
| |
p p
============================================
After that, the index 3 page is released by remove_from_page_cache().
Then we can make the situation that the tag is set with PAGECACHE_TAG_TOWRITE
and that the slot which corresponds to the tag is NULL.
===========================================
[roottag = DIRTY,TOWRITE]
|
tag [5 0 0 0]
[+ + x x]
| |
tag [0 0 0 1] [0 0 0 0]
[x x x +] [+ x x x]
| |
p p
(remove)
| | | | | | | | |
after calling remove_page_cache
| | | | | | | | |
v v v v v v v v v
[roottag = DIRTY,TOWRITE]
|
tag [4 0 0 0] * Only DIRTY tag is cleared
[x + x x] because no TOWRITE tag is existed
| in the bottom node.
[0 0 0 0]
[+ x x x]
|
p
============================================
To solve this problem
Change to that radix_tree_tag_if_tagged() doesn't tag the root tag
if it doesn't set any tags within the specified range.
Like this.
============================================
640 unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root
*root,
641 unsigned long *first_indexp, unsigned long last_index,
642 unsigned long nr_to_tag,
643 unsigned int iftag, unsigned int settag)
644 {
650 unsigned long tagged = 0;
...
733 if (tagged)
^^^^^^^^^^^^^^^^^^^^^^^^
734 root_tag_set(root, settag);
735 *first_indexp = index;
736
737 return tagged;
738 }
============================================
Signed-off-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
