blockdev: turn a rw semaphore into a percpu rw semaphore
This avoids cache line bouncing when many processes lock the semaphore
for read.
New percpu lock implementation
The lock consists of an array of percpu unsigned integers, a boolean
variable and a mutex.
When we take the lock for read, we enter rcu read section, check for a
"locked" variable. If it is false, we increase a percpu counter on the
current cpu and exit the rcu section. If "locked" is true, we exit the
rcu section, take the mutex and drop it (this waits until a writer
finished) and retry.
Unlocking for read just decreases percpu variable. Note that we can
unlock on a difference cpu than where we locked, in this case the
counter underflows. The sum of all percpu counters represents the number
of processes that hold the lock for read.
When we need to lock for write, we take the mutex, set "locked" variable
to true and synchronize rcu. Since RCU has been synchronized, no
processes can create new read locks. We wait until the sum of percpu
counters is zero - when it is, there are no readers in the critical
section.
Fix a crash when block device is read and block size is changed at the same time
The kernel may crash when block size is changed and I/O is issued
simultaneously.
Because some subsystems (udev or lvm) may read any block device anytime,
the bug actually puts any code that changes a block device size in
jeopardy.
The crash can be reproduced if you place "msleep(1000)" to
blkdev_get_blocks just before "bh->b_size = max_blocks <<
inode->i_blkbits;".
Then, run "dd if=/dev/ram0 of=/dev/null bs=4k count=1 iflag=direct"
While it is waiting in msleep, run "blockdev --setbsz 2048 /dev/ram0"
You get a BUG.
The direct and non-direct I/O is written with the assumption that block
size does not change. It doesn't seem practical to fix these crashes
one-by-one there may be many crash possibilities when block size changes
at a certain place and it is impossible to find them all and verify the
code.
This patch introduces a new rw-lock bd_block_size_semaphore. The lock is
taken for read during I/O. It is taken for write when changing block
size. Consequently, block size can't be changed while I/O is being
submitted.
For asynchronous I/O, the patch only prevents block size change while
the I/O is being submitted. The block size can change when the I/O is in
progress or when the I/O is being finished. This is acceptable because
there are no accesses to block size when asynchronous I/O is being
finished.
The patch prevents block size changing while the device is mapped with
mmap.
Oliver Chick [Fri, 21 Sep 2012 09:04:18 +0000 (10:04 +0100)]
xen/blkback: Change xen_vbd's flush_support and discard_secure to have type unsigned int, rather than bool
Changing the type of bdev parameters to be unsigned int :1, rather than bool.
This is more consistent with the types of other features in the block drivers.
Signed-off-by: Oliver Chick <oliver.chick@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
A queue newly allocated with blk_alloc_queue_node() has only
QUEUE_FLAG_BYPASS set. For request-based drivers,
blk_init_allocated_queue() is called and q->queue_flags is overwritten
with QUEUE_FLAG_DEFAULT which doesn't include BYPASS even though the
initial bypass is still in effect.
In blk_init_allocated_queue(), or QUEUE_FLAG_DEFAULT to q->queue_flags
instead of overwriting.
block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue()
b82d4b197c ("blkcg: make request_queue bypassing on allocation") made
request_queues bypassed on allocation to avoid switching on and off
bypass mode on a queue being initialized. Some drivers allocate and
then destroy a lot of queues without fully initializing them and
incurring bypass latency overhead on each of them could add upto
significant overhead.
Unfortunately, blk_init_allocated_queue() is never used by queues of
bio-based drivers, which means that all bio-based driver queues are in
bypass mode even after initialization and registration complete
successfully.
Due to the limited way request_queues are used by bio drivers, this
problem is hidden pretty well but it shows up when blk-throttle is
used in combination with a bio-based driver. Trying to configure
(echoing to cgroupfs file) blk-throttle for a bio-based driver hangs
indefinitely in blkg_conf_prep() waiting for bypass mode to end.
This patch moves the initial blk_queue_bypass_end() call from
blk_init_allocated_queue() to blk_register_queue() which is called for
any userland-visible queues regardless of its type.
I believe this is correct because I don't think there is any block
driver which needs or wants working elevator and blk-cgroup on a queue
which isn't visible to userland. If there are such users, we need a
different solution.
If the device supports WRITE SAME, use that to optimize zeroing of
blocks. If the device does not support WRITE SAME or if the operation
fails, fall back to writing zeroes the old-fashioned way.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
The WRITE SAME command supported on some SCSI devices allows the same
block to be efficiently replicated throughout a block range. Only a
single logical block is transferred from the host and the storage device
writes the same data to all blocks described by the I/O.
This patch implements support for WRITE SAME in the block layer. The
blkdev_issue_write_same() function can be used by filesystems and block
drivers to replicate a buffer across a block range. This can be used to
efficiently initialize software RAID devices, etc.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
block: Consolidate command flag and queue limit checks for merges
- blk_check_merge_flags() verifies that cmd_flags / bi_rw are
compatible. This function is called for both req-req and req-bio
merging.
- blk_rq_get_max_sectors() and blk_queue_get_max_sectors() can be used
to query the maximum sector count for a given request or queue. The
calls will return the right value from the queue limits given the
type of command (RW, discard, write same, etc.)
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Remove special-casing of non-rw fs style requests (discard). The nomerge
flags are consolidated in blk_types.h, and rq_mergeable() and
bio_mergeable() have been modified to use them.
bio_is_rw() is used in place of bio_has_data() a few places. This is
done to to distinguish true reads and writes from other fs type requests
that carry a payload (e.g. write same).
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
@unchanged exists@
position r.p1,r.p2;
expression e <= r.x,x,e1;
iterator I;
statement S;
@@
if (x@p1 == NULL) { ... when != I(x,...) S
when != e = e1
when != e += e1
when != e -= e1
when != ++e
when != --e
when != e++
when != e--
when != &e
kfree@p2(x); ... return ...; }
@ok depends on unchanged exists@
position any r.p1;
position r.p2;
expression x;
@@
... when != true x@p1 == NULL
kfree@p2(x);
@depends on !ok && unchanged@
position r.p2;
expression x;
@@
*kfree@p2(x);
// </smpl>
Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Jaehoon Chung [Fri, 31 Aug 2012 08:24:13 +0000 (17:24 +0900)]
block: remove the duplicated setting for congestion_threshold
Before call the blk_queue_congestion_threshold(),
the blk_queue_congestion_threshold() is already called at blk_queue_make_rquest().
Because this code is the duplicated, it has removed.
The memory return by kzalloc() or kmem_cache_zalloc() has already be set
to zero, so remove useless memset(0).
spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: Mike Miller <mike.miller@hp.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Stephen M. Cameron <scameron@beardog.cce.hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Dave Reisner [Sat, 8 Sep 2012 15:55:45 +0000 (11:55 -0400)]
block: reject invalid queue attribute values
Instead of using simple_strtoul which "converts" invalid numbers to 0,
use strict_strtoul and perform error checking to ensure that userspace
passes us a valid unsigned long. This addresses problems with functions
such as writev, which might want to write a trailing newline -- the
newline should rightfully be rejected, but the value preceeding it
should be preserved.
Fixes BZ#46981.
Signed-off-by: Dave Reisner <dreisner@archlinux.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Previously, there was bio_clone() but it only allocated from the fs bio
set; as a result various users were open coding it and using
__bio_clone().
This changes bio_clone() to become bio_clone_bioset(), and then we add
bio_clone() and bio_clone_kmalloc() as wrappers around it, making use of
the functionality the last patch adedd.
This will also help in a later patch changing how bio cloning works.
Previously, bio_kmalloc() and bio_alloc_bioset() behaved slightly
different because there was some almost-duplicated code - this fixes
some of that.
The important change is that previously bio_kmalloc() always set
bi_io_vec = bi_inline_vecs, even if nr_iovecs == 0 - unlike
bio_alloc_bioset(). This would cause bio_has_data() to return true; I
don't know if this resulted in any actual bugs but it was certainly
wrong.
bio_kmalloc() and bio_alloc_bioset() also have different arbitrary
limits on nr_iovecs - 1024 (UIO_MAXIOV) for bio_kmalloc(), 256
(BIO_MAX_PAGES) for bio_alloc_bioset(). This patch doesn't fix that, but
at least they're enforced closer together and hopefully they will be
fixed in a later patch.
This'll also help with some future cleanups - there are a fair number of
functions that allocate bios (e.g. bio_clone()), and now they don't have
to be duplicated for bio_alloc(), bio_alloc_bioset(), and bio_kmalloc().
Kent Overstreet [Thu, 6 Sep 2012 22:35:00 +0000 (15:35 -0700)]
block: Kill bi_destructor
Now that we've got generic code for freeing bios allocated from bio
pools, this isn't needed anymore.
This patch also makes bio_free() static, since without bi_destructor
there should be no need for it to be called anywhere else.
bio_free() is now only called from bio_put, so we can refactor those a
bit - move some code from bio_put() to bio_free() and kill the redundant
bio->bi_next = NULL.
v5: Switch to BIO_KMALLOC_POOL ((void *)~0), per Boaz
v6: BIO_KMALLOC_POOL now NULL, drop bio_free's EXPORT_SYMBOL
v7: No #define BIO_KMALLOC_POOL anymore
Kent Overstreet [Fri, 7 Sep 2012 20:44:02 +0000 (13:44 -0700)]
pktcdvd: Switch to bio_kmalloc()
This is prep work for killing bi_destructor - previously, pktcdvd had
its own pkt_bio_alloc which was basically duplication bio_kmalloc(),
necessitating its own bi_destructor implementation.
v5: Un-reorder some functions, to make the patch easier to review
Kent Overstreet [Thu, 6 Sep 2012 22:34:58 +0000 (15:34 -0700)]
block: Add bio_reset()
Reusing bios is something that's been highly frowned upon in the past,
but driver code keeps doing it anyways. If it's going to happen anyways,
we should provide a generic method.
This'll help with getting rid of bi_destructor - drivers/block/pktcdvd.c
was open coding it, by doing a bio_init() and resetting bi_destructor.
This required reordering struct bio, but the block layer is not yet
nearly fast enough for any cacheline effects to matter here.
v5: Add a define BIO_RESET_BITS, to be very explicit about what parts of
bio->bi_flags are saved.
v6: Further commenting verbosity, per Tejun
v9: Add a function comment
Kent Overstreet [Fri, 7 Sep 2012 20:44:01 +0000 (13:44 -0700)]
dm: Use bioset's front_pad for dm_rq_clone_bio_info
Previously, dm_rq_clone_bio_info needed to be freed by the bio's
destructor to avoid a memory leak in the blk_rq_prep_clone() error path.
This gets rid of a memory allocation and means we can kill
dm_rq_bio_destructor.
The _rq_bio_info_cache kmem cache is unused now and needs to be deleted,
but due to the way io_pool is used and overloaded this looks not quite
trivial so I'm leaving it for a later patch.
v6: Fix comment on struct dm_rq_clone_bio_info, per Tejun
Kent Overstreet [Thu, 6 Sep 2012 22:34:55 +0000 (15:34 -0700)]
block: Generalized bio pool freeing
With the old code, when you allocate a bio from a bio pool you have to
implement your own destructor that knows how to find the bio pool the
bio was originally allocated from.
This adds a new field to struct bio (bi_pool) and changes
bio_alloc_bioset() to use it. This makes various bio destructors
unnecessary, so they're then deleted.
v6: Explain the temporary if statement in bio_put
Signed-off-by: Kent Overstreet <koverstreet@google.com> CC: Jens Axboe <axboe@kernel.dk> CC: NeilBrown <neilb@suse.de> CC: Alasdair Kergon <agk@redhat.com> CC: Nicholas Bellinger <nab@linux-iscsi.org> CC: Lars Ellenberg <lars.ellenberg@linbit.com> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC bug fixes from Olof Johansson:
"Mostly Renesas and Atmel bugfixes this time, targeting boot and build
problems. A couple of patches for gemini and kirkwood as well. On a
whole nothing very controversial."
* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
ARM: gemini: fix the gemini build
ARM: shmobile: armadillo800eva: enable rw rootfs mount
ARM: Kirkwood: Fix 'SZ_1M' undeclared here for db88f6281-bp-setup.c
ARM: shmobile: mackerel: fixup usb module order
ARM: shmobile: armadillo800eva: fixup: sound card detection order
ARM: shmobile: marzen: fixup smsc911x id for regulator
ARM: at91/feature-removal-schedule: delay at91_mci removal
ARM: mach-shmobile: armadillo800eva: Enable power button as wakeup source
ARM: mach-shmobile: armadillo800eva: Fix GPIO buttons descriptions
ARM: at91/dts: remove partial parameter in at91sam9g25ek.dts
ARM: at91/clock: fix PLLA overclock warning
ARM: at91: fix rtc-at91sam9 irq issue due to sparse irq support
ARM: at91: fix system timer irq issue due to sparse irq support
ARM: shmobile: sh73a0: fixup RELOC_BASE of intca_irq_pins_desc
Merge tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging
Pull a hwmon fix from Guenter Roeck:
"One patch, fixing DIV_ROUND_CLOSEST to support negative dividends.
While the changes are not in the drivers/hwmon directory, the problem
primarily affects hwmon drivers, and it makes sense to push the patch
through the hwmon tree."
* tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
linux/kernel.h: Fix DIV_ROUND_CLOSEST to support negative dividends
Merge branch 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
Pull kbuild fixes from Michal Marek:
"These are two fixes that should go into 3.6. The link-vmlinux.sh one
is obvious.
The other one fixes make firmware_install with certain configurations,
where a file in the toplevel firmware tree gets installed first, and
$(INSTALL_FW_PATH)/$$(dir <file>) results in /lib/firmware/./, which
confuses make 3.82 for some reason."
* 'rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
firmware: fix directory creation rule matching with make 3.82
link-vmlinux.sh: Fix stray "echo" in error message
Merge tag 'mmc-fixes-for-3.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc
Pull MMC fixes from Chris Ball:
- a firmware bug on several Samsung MoviNAND eMMC models causes
permanent corruption on the device when secure erase and secure trim
requests are made, so we disable those requests on these eMMC devices.
- atmel-mci: fix a hang with some SD cards by waiting for not-busy flag.
- dw_mmc: low-power mode breaks SDIO interrupts; fix PIO error handling;
fix handling of error interrupts.
- mxs-mmc: fix deadlocks; fix compile error due to dma.h arch change.
- omap: fix broken PIO mode causing memory corruption.
- sdhci-esdhc: fix card detection.
* tag 'mmc-fixes-for-3.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc:
mmc: omap: fix broken PIO mode
mmc: card: Skip secure erase on MoviNAND; causes unrecoverable corruption.
mmc: dw_mmc: Disable low power mode if SDIO interrupts are used
mmc: dw_mmc: fix error handling in PIO mode
mmc: dw_mmc: correct mishandling error interrupt
mmc: dw_mmc: amend using error interrupt status
mmc: atmel-mci: not busy flag has also to be used for read operations
mmc: sdhci-esdhc: break out early if clock is 0
mmc: mxs-mmc: fix deadlock caused by recursion loop
mmc: mxs-mmc: fix deadlock in SDIO IRQ case
mmc: bfin_sdh: fix dma_desc_array build error
arch/um/os-Linux/time.c: In function 'deliver_alarm':
arch/um/os-Linux/time.c:117:3: error: too few arguments to function 'alarm_handler'
arch/um/os-Linux/internal.h:1:6: note: declared here
The error was introduced by commit d3c1cfcd ("um: pass siginfo to guest
process") in 3.6-rc1.
Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
Pull powerpc fixes from Benjamin Herrenschmidt:
"Here are a few fixes for 3.6 that were piling up while I was away or
busy (I was mostly MIA a week or two before San Diego).
Some fixes from Anton fixing up issues with our relatively new DSCR
control feature, and a few other fixes that are either regressions or
bugs nasty enough to warrant not waiting."
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc: Don't use __put_user() in patch_instruction
powerpc: Make sure IPI handlers see data written by IPI senders
powerpc: Restore correct DSCR in context switch
powerpc: Fix DSCR inheritance in copy_thread()
powerpc: Keep thread.dscr and thread.dscr_inherit in sync
powerpc: Update DSCR on all CPUs when writing sysfs dscr_default
powerpc/powernv: Always go into nap mode when CPU is offline
powerpc: Give hypervisor decrementer interrupts their own handler
powerpc/vphn: Fix arch_update_cpu_topology() return value
Merge tag 'gpio-fixes-for-v3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull GPIO fixes from Linus Walleij:
"These are some GPIO regression fixes for v3.6:
- Erroneous debug message from of_get_named_gpio_flags()
- Make sure the MC9S08DZ60 GPIO driver depend on I2C being compiled
in (not module) or allmodconfig breaks.
- Check return value from irq_alloc_descs() in the Emma Mobile GPIO
driver.
- Assign the owner field for the rdc321x driver so the module won't
be removed if it has active GPIOs."
* tag 'gpio-fixes-for-v3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
gpio: rdc321x: Prevent removal of modules exporting active GPIOs
gpio: em: Fix checking return value of irq_alloc_descs
gpio: mc9s08dz60: Fix build error if I2C=m
gpio: Fix debug message in of_get_named_gpio_flags()
Merge tag 'sound-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull sound fixes from Takashi Iwai:
"There are nothing scaring, contains only small fixes for HD-audio and
USB-audio:
- EPSS regression fix and GPIO fix for HD-audio IDT codecs
- A series of USB-audio regression fixes that are found since 3.5
kernel"
* tag 'sound-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: snd-usb: fix cross-interface streaming devices
ALSA: snd-usb: fix calls to next_packet_size
ALSA: snd-usb: restore delay information
ALSA: snd-usb: use list_for_each_safe for endpoint resources
ALSA: snd-usb: Fix URB cancellation at stream start
ALSA: hda - Don't trust codec EPSS bit for IDT 92HD83xx & co
ALSA: hda - Avoid unnecessary parameter read for EPSS
ALSA: hda - Do not set GPIOs for speakers on IDT if there are no speakers
* tag 'fbdev-fixes-for-3.6-1' of git://github.com/schandinat/linux-2.6:
OMAPFB: fix framebuffer console colors
OMAPDSS: Fix SDI PLL locking
video: mb862xxfb: prevent divide by zero bug
drivers/video/auo_k190x.c: drop kfree of devm_kzalloc's data
fbcon: Fix bit_putcs() call to kmalloc(s, GFP_KERNEL)
fbcon: prevent possible buffer overflow.
Merge tag 'upstream-3.6-rc5' of git://git.infradead.org/linux-ubi
Pull ubi fix from Artem Bityutskiy:
"A single small fix for memory deallocation: we allocated memory using
'kmem_cache_alloc()' but were freeing it using 'kfree()' in some
cases. Now we fix this by using 'kmem_cache_free()' instead."
* tag 'upstream-3.6-rc5' of git://git.infradead.org/linux-ubi:
UBI: fix a horrible memory deallocation bug
Fix order of arguments to compat_put_time[spec|val]
Commit 644595f89620 ("compat: Handle COMPAT_USE_64BIT_TIME in
net/socket.c") introduced a bug where the helper functions to take
either a 64-bit or compat time[spec|val] got the arguments in the wrong
order, passing the kernel stack pointer off as a user pointer (and vice
versa).
Because of the user address range check, that in turn then causes an
EFAULT due to the user pointer range checking failing for the kernel
address. Incorrectly resuling in a failed system call for 32-bit
processes with a 64-bit kernel.
On odder architectures like HP-PA (with separate user/kernel address
spaces), it can be used read kernel memory.
powerpc: Don't use __put_user() in patch_instruction
patch_instruction() can be called very early on ppc32, when the kernel
isn't yet running at it's linked address. That can cause the !
is_kernel_addr() test in __put_user() to trip and call might_sleep()
which is very bad at that point during boot.
Use a lower level function instead for now, at least until we get to
rework ppc32 boot process to do the code patching later, like ppc64
does.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Paul Mackerras [Tue, 4 Sep 2012 18:33:08 +0000 (18:33 +0000)]
powerpc: Make sure IPI handlers see data written by IPI senders
We have been observing hangs, both of KVM guest vcpu tasks and more
generally, where a process that is woken doesn't properly wake up and
continue to run, but instead sticks in TASK_WAKING state. This
happens because the update of rq->wake_list in ttwu_queue_remote()
is not ordered with the update of ipi_message in
smp_muxed_ipi_message_pass(), and the reading of rq->wake_list in
scheduler_ipi() is not ordered with the reading of ipi_message in
smp_ipi_demux(). Thus it is possible for the IPI receiver not to see
the updated rq->wake_list and therefore conclude that there is nothing
for it to do.
In order to make sure that anything done before smp_send_reschedule()
is ordered before anything done in the resulting call to scheduler_ipi(),
this adds barriers in smp_muxed_message_pass() and smp_ipi_demux().
The barrier in smp_muxed_message_pass() is a full barrier to ensure that
there is a full ordering between the smp_send_reschedule() caller and
scheduler_ipi(). In smp_ipi_demux(), we use xchg() rather than
xchg_local() because xchg() includes release and acquire barriers.
Using xchg() rather than xchg_local() makes sense given that
ipi_message is not just accessed locally.
This moves the barrier between setting the message and calling the
cause_ipi() function into the individual cause_ipi implementations.
Most of them -- those that used outb, out_8 or similar -- already had
a full barrier because out_8 etc. include a sync before the MMIO
store. This adds an explicit barrier in the two remaining cases.
These changes made no measurable difference to the speed of IPIs as
measured using a simple ping-pong latency test across two CPUs on
different cores of a POWER7 machine.
The analysis of the reason why processes were not waking up properly
is due to Milton Miller.
Cc: stable@vger.kernel.org # v3.0+ Reported-by: Milton Miller <miltonm@bga.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Anton Blanchard [Mon, 3 Sep 2012 16:51:10 +0000 (16:51 +0000)]
powerpc: Restore correct DSCR in context switch
During a context switch we always restore the per thread DSCR value.
If we aren't doing explicit DSCR management
(ie thread.dscr_inherit == 0) and the default DSCR changed while
the process has been sleeping we end up with the wrong value.
Check thread.dscr_inherit and select the default DSCR or per thread
DSCR as required.
This was found with the following test case, when running with
more threads than CPUs (ie forcing context switching):
Anton Blanchard [Mon, 3 Sep 2012 16:49:47 +0000 (16:49 +0000)]
powerpc: Fix DSCR inheritance in copy_thread()
If the default DSCR is non zero we set thread.dscr_inherit in
copy_thread() meaning the new thread and all its children will ignore
future updates to the default DSCR. This is not intended and is
a change in behaviour that a number of our users have hit.
We just need to inherit thread.dscr and thread.dscr_inherit from
the parent which ends up being much simpler.
Anton Blanchard [Mon, 3 Sep 2012 16:48:46 +0000 (16:48 +0000)]
powerpc: Keep thread.dscr and thread.dscr_inherit in sync
When we update the DSCR either via emulation of mtspr(DSCR) or via
a change to dscr_default in sysfs we don't update thread.dscr.
We will eventually update it at context switch time but there is
a period where thread.dscr is incorrect.
If we fork at this point we will copy the old value of thread.dscr
into the child. To avoid this, always keep thread.dscr in sync with
reality.
Anton Blanchard [Mon, 3 Sep 2012 16:47:56 +0000 (16:47 +0000)]
powerpc: Update DSCR on all CPUs when writing sysfs dscr_default
Writing to dscr_default in sysfs doesn't actually change the DSCR -
we rely on a context switch on each CPU to do the work. There is no
guarantee we will get a context switch in a reasonable amount of time
so fire off an IPI to force an immediate change.
This issue was found with the following test case:
Paul Mackerras [Thu, 26 Jul 2012 18:51:09 +0000 (18:51 +0000)]
powerpc/powernv: Always go into nap mode when CPU is offline
The CPU hotplug code for the powernv platform currently only puts
offline CPUs into nap mode if the powersave_nap variable is set.
However, HV-style KVM on this platform requires secondary CPU threads
to be offline and in nap mode. Since we know nap mode works just
fine on all POWER7 machines, and the only machines that support the
powernv platform are POWER7 machines, this changes the code to
always put offline CPUs into nap mode, regardless of powersave_nap.
Powersave_nap still controls whether or not CPUs go into nap mode
when idle, as before.
Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Paul Mackerras [Thu, 26 Jul 2012 13:56:11 +0000 (13:56 +0000)]
powerpc: Give hypervisor decrementer interrupts their own handler
At the moment the handler for hypervisor decrementer interrupts is
the same as for decrementer interrupts, i.e. timer_interrupt().
This is bogus; if we ever do get a hypervisor decrementer interrupt
it won't have anything to do with the next timer event. In fact
the only time we get hypervisor decrementer interrupts is when one
is left pending on exit from a KVM guest.
When we get a hypervisor decrementer interrupt we don't need to do
anything special to clear it, since they are edge-triggered on the
transition of HDEC from 0 to -1. Thus this adds an empty handler
function for them. We don't need to have them masked when interrupts
are soft-disabled, so we use STD_EXCEPTION_HV instead of
MASKABLE_EXCEPTION_HV.
Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Linus Walleij [Thu, 30 Aug 2012 17:22:36 +0000 (19:22 +0200)]
ARM: gemini: fix the gemini build
Test-compiling obscure machines I notice that the gemini (which
by the way lacks a defconfig) is broken since some time back.
Adding a simple missing include makes it build again.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Olof Johansson <olof@lixom.net>
[ 2.086181] Waiting for root device /dev/mmcblk0p1...
[ 2.324066] Unhandled fault: imprecise external abort (0x406) at 0x00000000
[ 2.331451] Internal error: : 406 [#1] ARM
[ 2.335784] Modules linked in:
[ 2.339050] CPU: 0 Not tainted (3.6.0-rc3 #60)
[ 2.344146] PC is at default_idle+0x28/0x30
[ 2.348602] LR is at trace_hardirqs_on_caller+0x15c/0x1b0
...
This turned out to be due to memory corruption caused by long-broken
PIO code in drivers/mmc/host/omap.c. (Previously, this driver had
been using DMA; but the above commit caused the MMC driver to fall
back to PIO mode with an unmodified Kconfig.)
The PIO code, added with the rest of the driver in commit 730c9b7e6630f786fcec026fb11d2e6f2c90fdcb ("[MMC] Add OMAP MMC host
driver"), confused bytes with 16-bit words. This bug caused memory
located after the PIO transfer buffer to be corrupted with transfers
larger than 32 bytes. The driver also did not increment the buffer
pointer after the transfer occurred. This bug resulted in data
corruption during any transfer larger than 64 bytes.
Signed-off-by: Paul Walmsley <paul@pwsan.com> Reviewed-by: Felipe Balbi <balbi@ti.com> Tested-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Chris Ball <cjb@laptop.org>
Ian Chen [Wed, 29 Aug 2012 06:05:36 +0000 (15:05 +0900)]
mmc: card: Skip secure erase on MoviNAND; causes unrecoverable corruption.
For several MoviNAND eMMC parts, there are known issues with secure
erase and secure trim. For these specific MoviNAND devices, we skip
these operations.
Specifically, there is a bug in the eMMC firmware that causes
unrecoverable corruption when the MMC is erased with MMC_CAP_ERASE
enabled.
Doug Anderson [Wed, 25 Jul 2012 15:33:17 +0000 (08:33 -0700)]
mmc: dw_mmc: Disable low power mode if SDIO interrupts are used
The documentation for the dw_mmc part says that the low power
mode should normally only be set for MMC and SD memory and should
be turned off for SDIO cards that need interrupts detected.
The best place I could find to do this is when the SDIO interrupt
was first enabled. I rely on the fact that dw_mci_setup_bus()
will be called when it's time to reenable.
Signed-off-by: Doug Anderson <dianders@chromium.org> Acked-by: Seungwon Jeon <tgih.jun@samsung.com> Signed-off-by: Chris Ball <cjb@laptop.org>
Seungwon Jeon [Wed, 1 Aug 2012 00:30:46 +0000 (09:30 +0900)]
mmc: dw_mmc: fix error handling in PIO mode
Data transfer will be continued until all the bytes are transmitted,
even if data crc error occurs during a multiple-block data transfer.
This means RXDR/TXDR interrupts will occurs until data transfer is
terminated. Early setting of host->sg to NULL prevents going into
xxx_data_pio functions, hence permanent unhandled RXDR/TXDR interrupts
occurs. And checking error interrupt status in the xxx_data_pio functions
is no need because dw_mci_interrupt does do the same. This patch also
removes it.
Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com> Acked-by: Jaehoon Chung <jh80.chung@samsung.com> Acked-by: Will Newton <will.newton@imgtec.com> Signed-off-by: Chris Ball <cjb@laptop.org>
Seungwon Jeon [Wed, 1 Aug 2012 00:30:40 +0000 (09:30 +0900)]
mmc: dw_mmc: correct mishandling error interrupt
Datasheet of SYNOPSYS mentions that DTO(Data Transfer Over) interrupt
will be raised even if some error interrupts, however it is actually
found that DTO does not occur. SYNOPSYS has confirmed this issue.
Current implementation defers the call of tasklet_schedule until DTO
when the error interrupts is happened. This patch fixes error handling.
Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com> Acked-by: Jaehoon Chung <jh80.chung@samsung.com> Acked-by: Will Newton <will.newton@imgtec.com> Signed-off-by: Chris Ball <cjb@laptop.org>
Seungwon Jeon [Wed, 1 Aug 2012 00:30:30 +0000 (09:30 +0900)]
mmc: dw_mmc: amend using error interrupt status
RINTSTS status includes masked interrupts as well as unmasked.
data_status and cmd_status are set by value of RINTSTS in interrupt handler
and tasklet finally uses it to decide whether error is happened or not.
In addition, MINTSTS status is used for setting data_status in PIO.
Masked error interrupt will not be handled and that status can be considered
non-error case.
Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Reviewed By: Girish K S <girish.shivananjappa@linaro.org> Acked-by: Jaehoon Chung <jh80.chung@samsung.com> Acked-by: Will Newton <will.newton@imgtec.com> Signed-off-by: Chris Ball <cjb@laptop.org>
mmc: atmel-mci: not busy flag has also to be used for read operations
Even if the datasheet says that the not busy flag has to be used only
for write operations, it's false except for version lesser than v2xx.
Not waiting on the not busy flag for read operations can cause the
controller to hang-up during the initialization of some SD cards
with DMA after the first CMD6 -- the next command is sent too early.
Shawn Guo [Wed, 22 Aug 2012 15:10:01 +0000 (23:10 +0800)]
mmc: sdhci-esdhc: break out early if clock is 0
Since commit 30832ab56 ("mmc: sdhci: Always pass clock request value
zero to set_clock host op") was merged, esdhc_set_clock starts hitting
"if (clock == 0)" where ESDHC_SYSTEM_CONTROL has been operated. This
causes SDHCI card-detection function being broken. Fix the regression
by moving "if (clock == 0)" above ESDHC_SYSTEM_CONTROL operation.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Cc: <stable@vger.kernel.org> Signed-off-by: Chris Ball <cjb@laptop.org>
UBI was mistakingly using 'kfree()' instead of 'kmem_cache_free()' when
freeing "attach eraseblock" structures in vtbl.c. Thankfully, this happened
only when we were doing auto-format, so many systems were unaffected. However,
there are still many users affected.
It is strange, but the system did not crash and nothing bad happened when
the SLUB memory allocator was used. However, in case of SLOB we observed an
crash right away.
This problem was introduced in 2.6.39 by commit
"6c1e875 UBI: add slab cache for ubi_scan_leb objects"
A note for stable trees:
Because variable were renamed, this won't cleanly apply to older kernels.
Changing names like this should help:
1. ai -> si
2. aeb_slab_cache -> seb_slab_cache
3. new_aeb -> new_seb
Reported-by: Richard Genoud <richard.genoud@gmail.com> Tested-by: Richard Genoud <richard.genoud@gmail.com> Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: stable@vger.kernel.org [v2.6.39+] Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
This is a small cleanup, that also may turn error handling of
unitialized disks more readable. We don't need a separate variable to
track allocated disks, remove dr and reuse drive variable instead.
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
floppy: use common function to check if floppies can be registered
The same checks to see if a drive can be or is registered are
repeated through the code, factor out the checks in a common function
and replace the repeated checks with it.
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Ben Hutchings [Mon, 27 Aug 2012 23:56:53 +0000 (20:56 -0300)]
genhd: Make put_disk() safe for disks that have not been registered
Since commit 523e1d3 ('block: make gendisk hold a reference to its
queue'), add_disk() adds a reference to disk->queue, which is then
dropped by disk_release(). But if a disk is destroyed without being
registered through add_disk() (or if add_disk() fails at the first
hurdle) then we have a reference imbalance.
Use the GENHD_FL_UP flag to tell whether this extra reference has been
added. Remove the incomplete workaround from the floppy driver.
Cc: stable@vger.kernel.org Acked-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
floppy: don't call alloc_ordered_workqueue inside the alloc_disk loop
Since commit 070ad7e ("floppy: convert to delayed work and single-thread
wq"), we end up calling alloc_ordered_workqueue multiple times inside
the loop, which shouldn't be intended. Besides the leak, other side
effect in the current code is if blk_init_queue fails, we would end up
calling unregister_blkdev even if we didn't call yet register_blkdev.
Just moved the allocation of floppy_wq before the loop, and adjusted the
code accordingly.
ARM: shmobile: armadillo800eva: enable rw rootfs mount
armadillo800eva default boot loader is "hermit",
and it's tag->u.core.flags has flag when kernel boots.
Because of this, ${LINUX}/arch/arm/kernel/setup.c :: parse_tag_core()
didn't remove MS_RDONLY flag from root_mountflags.
Thus, the rootfs is mounted as "readonly".
This patch adds "rw" kernel parameter,
and enable read/write mounts for rootfs
projects / karo-tx-linux.git / log