No need for silly open coding - and struct sg_iovec has exactly the same
layout as struct iovec...
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch enables the sysfs to control I/O request merge
functionality in the plug list. While this control has been
implemented for the request queue, it was dismissed in the plug list.
Therefore, block layer merges requests together (or attempt to merge)
even if the merge capability was disable using sysfs nomerge parameter
value 2.
This limitation is directly affects functionality of io_submit()
system call. The system call enables user to submit a bunch of IO
requests from user space using struct iocb **ios input argument.
However, the unconditioned merging functionality in the plug list
potentially merges these requests together down the road. Therefore,
there is no way to distinguish between an application sending bunch of
sequential IOs and an application sending one big IO. Ultimately, all
requests generated by the former app merge within the plug list
together and looks similar to the second app.
While the merging functionality is a desirable feature to improve the
performance of IO subsystem for some applications, it is not useful
for other application like ours at all.
Signed-off-by: Alireza Haghdoost <alireza@cs.umn.edu>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Coding style modified.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Without this patch all DM devices will default to BLK_MAX_SEGMENT_SIZE
(65536) even if the underlying device(s) have a larger value -- this is
due to blk_stack_limits() using min_not_zero() when stacking the
max_segment_size limit.
1073741824
before patch:
65536
after patch:
1073741824
Reported-by: Lukasz Flis <l.flis@cyfronet.pl>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # v3.3+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add locking of q->sysfs_lock into elevator_change() (an exported function)
to ensure it is held to protect q->elevator from elevator_init(), even if
elevator_change() is called from non-sysfs paths.
sysfs path (elv_iosched_store) uses __elevator_change(), non-locking
version, as the lock is already taken by elv_iosched_store().
Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The soft lockup below happens at the boot time of the system using dm
multipath and the udev rules to switch scheduler.
[ 356.127001] BUG: soft lockup - CPU#3 stuck for 22s! [sh:483]
[ 356.127001] RIP: 0010:[<ffffffff81072a7d>] [<ffffffff81072a7d>] lock_timer_base.isra.35+0x1d/0x50
...
[ 356.127001] Call Trace:
[ 356.127001] [<ffffffff81073810>] try_to_del_timer_sync+0x20/0x70
[ 356.127001] [<ffffffff8118b08a>] ? kmem_cache_alloc_node_trace+0x20a/0x230
[ 356.127001] [<ffffffff810738b2>] del_timer_sync+0x52/0x60
[ 356.127001] [<ffffffff812ece22>] cfq_exit_queue+0x32/0xf0
[ 356.127001] [<ffffffff812c98df>] elevator_exit+0x2f/0x50
[ 356.127001] [<ffffffff812c9f21>] elevator_change+0xf1/0x1c0
[ 356.127001] [<ffffffff812caa50>] elv_iosched_store+0x20/0x50
[ 356.127001] [<ffffffff812d1d09>] queue_attr_store+0x59/0xb0
[ 356.127001] [<ffffffff812143f6>] sysfs_write_file+0xc6/0x140
[ 356.127001] [<ffffffff811a326d>] vfs_write+0xbd/0x1e0
[ 356.127001] [<ffffffff811a3ca9>] SyS_write+0x49/0xa0
[ 356.127001] [<ffffffff8164e899>] system_call_fastpath+0x16/0x1b
This is caused by a race between md device initialization by multipathd and
shell script to switch the scheduler using sysfs.
- multipathd:
SyS_ioctl -> do_vfs_ioctl -> dm_ctl_ioctl -> ctl_ioctl -> table_load
-> dm_setup_md_queue -> blk_init_allocated_queue -> elevator_init
q->elevator = elevator_alloc(q, e); // not yet initialized
- sh -c 'echo deadline > /sys/$DEVPATH/queue/scheduler':
elevator_switch (in the call trace above)
struct elevator_queue *old = q->elevator;
q->elevator = elevator_alloc(q, new_e);
elevator_exit(old); // lockup! (*)
- multipathd: (cont.)
err = e->ops.elevator_init_fn(q); // init fails; q->elevator is modified
(*) When del_timer_sync() is called, lock_timer_base() will loop infinitely
while timer->base == NULL. In this case, as timer will never initialized,
it results in lockup.
This patch introduces acquisition of q->sysfs_lock around elevator_init()
into blk_init_allocated_queue(), to provide mutual exclusion between
initialization of the q->scheduler and switching of the scheduler.
This should fix this bugzilla:
https://bugzilla.redhat.com/show_bug.cgi?id=902012
Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__get_cpu_var() is used for multiple purposes in the kernel source. One of
them is address calculation via the form &__get_cpu_var(x). This calculates
the address for the instance of the percpu variable of the current processor
based on an offset.
Other use cases are for storing and retrieving data from the current
processors percpu area. __get_cpu_var() can be used as an lvalue when
writing data or on the right side of an assignment.
__get_cpu_var() is defined as :
#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))
__get_cpu_var() always only does an address determination. However, store
and retrieve operations could use a segment prefix (or global register on
other platforms) to avoid the address calculation.
this_cpu_write() and this_cpu_read() can directly take an offset into a
percpu area and use optimized assembly code to read and write per cpu
variables.
This patch converts __get_cpu_var into either an explicit address
calculation using this_cpu_ptr() or into a use of this_cpu operations that
use the offset. Thereby address calculations are avoided and less registers
are used when code is generated.
At the end of the patch set all uses of __get_cpu_var have been removed so
the macro is removed too.
The patch set includes passes over all arches as well. Once these operations
are used throughout then specialized macros can be defined in non -x86
arches as well in order to optimize per cpu access by f.e. using a global
register that may be set to the per cpu base.
Transformations done to __get_cpu_var()
1. Determine the address of the percpu instance of the current processor.
DEFINE_PER_CPU(int, y);
int *x = &__get_cpu_var(y);
Converts to
int *x = this_cpu_ptr(&y);
2. Same as #1 but this time an array structure is involved.
DEFINE_PER_CPU(int, y[20]);
int *x = __get_cpu_var(y);
Converts to
int *x = this_cpu_ptr(y);
3. Retrieve the content of the current processors instance of a per cpu
variable.
DEFINE_PER_CPU(int, y);
int x = __get_cpu_var(y)
Converts to
int x = __this_cpu_read(y);
4. Retrieve the content of a percpu struct
DEFINE_PER_CPU(struct mystruct, y);
struct mystruct x = __get_cpu_var(y);
Converts to
memcpy(&x, this_cpu_ptr(&y), sizeof(x));
5. Assignment to a per cpu variable
DEFINE_PER_CPU(int, y)
__get_cpu_var(y) = x;
Converts to
this_cpu_write(y, x);
6. Increment/Decrement etc of a per cpu variable
DEFINE_PER_CPU(int, y);
__get_cpu_var(y)++
Converts to
this_cpu_inc(y)
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There were two places where return value from bdi_init was not tested.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
crocode i2c_i801 i2c_core iTCO_wdt iTCO_vendor_support shpchp ioatdma dca be2net sg ses enclosure ext4 mbcache jbd2 sd_mod crc_t10dif ahci megaraid_sas(U) dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]
Pid: 491, comm: scsi_eh_0 Tainted: G W ---------------- 2.6.32-220.13.1.el6.x86_64 #1 IBM -[8722PAX]-/00D1461
RIP: 0010:[<ffffffff8124e424>] [<ffffffff8124e424>] blk_requeue_request+0x94/0xa0
RSP: 0018:ffff881057eefd60 EFLAGS: 00010012
RAX: ffff881d99e3e8a8 RBX: ffff881d99e3e780 RCX: ffff881d99e3e8a8
RDX: ffff881d99e3e8a8 RSI: ffff881d99e3e780 RDI: ffff881d99e3e780
RBP: ffff881057eefd80 R08: ffff881057eefe90 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff881057f92338
R13: 0000000000000000 R14: ffff881057f92338 R15: ffff883058188000
FS: 0000000000000000(0000) GS:ffff880040200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 00000000006d3ec0 CR3: 000000302cd7d000 CR4: 00000000000406b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process scsi_eh_0 (pid: 491, threadinfo ffff881057eee000, task ffff881057e29540)
Stack:
0000000000001057 0000000000000286 ffff8810275efdc0 ffff881057f16000
<0> ffff881057eefdd0 ffffffff81362323 ffff881057eefe20 ffffffff8135f393
<0> ffff881057e29af8 ffff8810275efdc0 ffff881057eefe78 ffff881057eefe90
Call Trace:
[<ffffffff81362323>] __scsi_queue_insert+0xa3/0x150
[<ffffffff8135f393>] ? scsi_eh_ready_devs+0x5e3/0x850
[<ffffffff81362a23>] scsi_queue_insert+0x13/0x20
[<ffffffff8135e4d4>] scsi_eh_flush_done_q+0x104/0x160
[<ffffffff8135fb6b>] scsi_error_handler+0x35b/0x660
[<ffffffff8135f810>] ? scsi_error_handler+0x0/0x660
[<ffffffff810908c6>] kthread+0x96/0xa0
[<ffffffff8100c14a>] child_rip+0xa/0x20
[<ffffffff81090830>] ? kthread+0x0/0xa0
[<ffffffff8100c140>] ? child_rip+0x0/0x20
Code: 00 00 eb d1 4c 8b 2d 3c 8f 97 00 4d 85 ed 74 bf 49 8b 45 00 49 83 c5 08 48 89 de 4c 89 e7 ff d0 49 8b 45 00 48 85 c0 75 eb eb a4 <0f> 0b eb fe 0f 1f 84 00 00 00 00 00 55 48 89 e5 0f 1f 44 00 00
RIP [<ffffffff8124e424>] blk_requeue_request+0x94/0xa0
RSP <ffff881057eefd60>
The RIP is this line:
BUG_ON(blk_queued_rq(rq));
After digging through the code, I think there may be a race between the
request completion and the timer handler running.
A timer is started for each request put on the device's queue (see
blk_start_request->blk_add_timer). If the request does not complete
before the timer expires, the timer handler (blk_rq_timed_out_timer)
will mark the request complete atomically:
static inline int blk_mark_rq_complete(struct request *rq)
{
return test_and_set_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
}
and then call blk_rq_timed_out. The latter function will call
scsi_times_out, which will return one of BLK_EH_HANDLED,
BLK_EH_RESET_TIMER or BLK_EH_NOT_HANDLED. If BLK_EH_RESET_TIMER is
returned, blk_clear_rq_complete is called, and blk_add_timer is again
called to simply wait longer for the request to complete.
Now, if the request happens to complete while this is going on, what
happens? Given that we know the completion handler will bail if it
finds the REQ_ATOM_COMPLETE bit set, we need to focus on the completion
handler running after that bit is cleared. So, from the above
paragraph, after the call to blk_clear_rq_complete. If the completion
sets REQ_ATOM_COMPLETE before the BUG_ON in blk_add_timer, we go boom
there (I haven't seen this in the cores). Next, if we get the
completion before the call to list_add_tail, then the timer will
eventually fire for an old req, which may either be freed or reallocated
(there is evidence that this might be the case). Finally, if the
completion comes in *after* the addition to the timeout list, I think
it's harmless. The request will be removed from the timeout list,
req_atom_complete will be set, and all will be well.
This will only actually explain the coredumps *IF* the request
structure was freed, reallocated *and* queued before the error handler
thread had a chance to process it. That is possible, but it may make
sense to keep digging for another race. I think that if this is what
was happening, we would see other instances of this problem showing up
as null pointer or garbage pointer dereferences, for example when the
request structure was not re-used. It looks like we actually do run
into that situation in other reports.
This patch moves the BUG_ON(test_bit(REQ_ATOM_COMPLETE,
&req->atomic_flags)); from blk_add_timer to the only caller that could
trip over it (blk_start_request). It then inverts the calls to
blk_clear_rq_complete and blk_add_timer in blk_rq_timed_out to address
the race. I've boot tested this patch, but nothing more.
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Hannes Reinecke <hare@suse.de>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently each task sends BLK_TN_PROCESS event to the first traced
device it interacts with after a new trace is started. When there are
several traced devices and the task accesses more devices, this logic
can result in BLK_TN_PROCESS being sent several times to some devices
while it is never sent to other devices. Thus blkparse doesn't display
command name when parsing some blktrace files.
Fix the problem by sending BLK_TN_PROCESS event to all traced devices
when a task interacts with any of them.
Signed-off-by: Jan Kara <jack@suse.cz>
Review-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Some additional fixes for v3.13, the majority of which are removals and
downgrades of BUG()s from Takashi.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.15 (GNU/Linux)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=osG+
-----END PGP SIGNATURE-----
Merge tag 'asoc-v3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
ASoC: Updates for v3.13
Some additional fixes for v3.13, the majority of which are removals and
downgrades of BUG()s from Takashi.
Fix mmap2 behaviour which incorrectly works with pgoff
not in 4k units.
Reported-by: Rich Felker <dalias@aerifal.cx>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
New codec ALC255/ALC3234 support multifunction jacks.
It used for menual select the input device.
Signed-off-by: Kailang Yang <kailang@realtek.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The commit [8fe7b65ab4: ALSA: hda - Apply GPIO setup for MacBooks
with CS4208] added a fixup entry matching with the vendor id 0x106b.
This broke the fixups for previous MBA6,1 and 6,2, since the PCI SSID
vendor id matches before evaluating the codec SSIDs.
We had a similar issue on Mac with Sigmatel codecs, and solve this
problem again similarly, by introducing a skeleton entry matching with
the all MacBooks, then remap to the right one.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=64401
Fixes: 8fe7b65ab4 ('ALSA: hda - Apply GPIO setup for MacBooks with CS4208')
Cc: <stable@vger.kernel.org> [v3.12+]
Signed-off-by: Takashi Iwai <tiwai@suse.de>
If "nid == MAX_NUMNODES" then we write beyond the end of the node_data[]
array.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
