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commit 5a0ec388ef0f6e33841aeb810d7fa23f049ec4cd upstream.
Commit 523e1d399ce0 ("block: make gendisk hold a reference to its queue")
modified add_disk() and disk_release() but did not update any of the
error paths that trigger a put_disk() call after disk->queue has been
assigned. That introduced the following behavior in the pktcdvd driver
if pkt_new_dev() fails:
Kernel BUG at 00000000e98fd882 [verbose debug info unavailable]
Since disk_release() calls blk_put_queue() anyway if disk->queue != NULL,
fix this by removing the blk_cleanup_queue() call from the pkt_setup_dev()
error path.
Fixes: commit 523e1d399ce0 ("block: make gendisk hold a reference to its queue")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ae6650163c66a7eff1acd6eb8b0f752dcfa8eba5 upstream.
范龙飞 reports that KASAN can report a use-after-free in __lock_acquire.
The reason is due to insufficient serialization in lo_release(), which
will continue to use the loop device even after it has decremented the
lo_refcnt to zero.
In the meantime, another process can come in, open the loop device
again as it is being shut down. Confusion ensues.
Reported-by: 范龙飞 <long7573@126.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 21acdf45f4958135940f0b4767185cf911d4b010 upstream.
Commit d3834fefcfe5 ("rbd: bump queue_max_segments") bumped
max_segments (unsigned short) to max_hw_sectors (unsigned int).
max_hw_sectors is set to the number of 512-byte sectors in an object
and overflows unsigned short for 32M (largest possible) objects, making
the block layer resort to handing us single segment (i.e. single page
or even smaller) bios in that case.
Fixes: d3834fefcfe5 ("rbd: bump queue_max_segments")
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 0bc315381fe9ed9fb91db8b0e82171b645ac008f ]
zram can handle at most SECTORS_PER_PAGE sectors in a bio's bvec. When using
the NVMe over Fabrics loopback target which potentially sends a huge bulk of
pages attached to the bio's bvec this results in a kernel panic because of
array out of bounds accesses in zram_decompress_page().
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 089bc0143f489bd3a4578bdff5f4ca68fb26f341 upstream.
Rather than constructing a local structure instance on the stack, fill
the fields directly on the shared ring, just like other backends do.
Build on the fact that all response structure flavors are actually
identical (the old code did make this assumption too).
This is XSA-216.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
[bwh: Backported to 4.4: adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 1e37f2f84680fa7f8394fd444b6928e334495ccc upstream.
rbd_img_obj_exists_submit() and rbd_img_obj_parent_read_full() are on
the writeback path for cloned images -- we attempt a stat on the parent
object to see if it exists and potentially read it in to call copyup.
GFP_NOIO should be used instead of GFP_KERNEL here.
Link: http://tracker.ceph.com/issues/22014
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: David Disseldorp <ddiss@suse.de>
[idryomov@gmail.com: backport to < 4.9: context]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5fbd545cd3fd311ea1d6e8be4cedddd0ee5684c7 upstream.
Ensure that the members of struct skd_msg_buf have been transferred
to the PCIe adapter before the doorbell is triggered. This patch
avoids that I/O fails sporadically and that the following error
message is reported:
(skd0:STM000196603:[0000:00:09.0]): Completion mismatch comp_id=0x0000 skreq=0x0400 new=0x0000
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7277cc67b3916eed47558c64f9c9c0de00a35cda upstream.
Since put_disk() triggers a disk_release() call and since that
last function calls blk_put_queue() if disk->queue != NULL, clear
the disk->queue pointer before calling put_disk(). This avoids
that unloading the skd kernel module triggers the following
use-after-free:
WARNING: CPU: 8 PID: 297 at lib/refcount.c:128 refcount_sub_and_test+0x70/0x80
refcount_t: underflow; use-after-free.
CPU: 8 PID: 297 Comm: kworker/8:1 Not tainted 4.11.10-300.fc26.x86_64 #1
Workqueue: events work_for_cpu_fn
Call Trace:
dump_stack+0x63/0x84
__warn+0xcb/0xf0
warn_slowpath_fmt+0x5a/0x80
refcount_sub_and_test+0x70/0x80
refcount_dec_and_test+0x11/0x20
kobject_put+0x1f/0x50
blk_put_queue+0x15/0x20
disk_release+0xae/0xf0
device_release+0x32/0x90
kobject_release+0x67/0x170
kobject_put+0x2b/0x50
put_disk+0x17/0x20
skd_destruct+0x5c/0x890 [skd]
skd_pci_probe+0x124d/0x13a0 [skd]
local_pci_probe+0x42/0xa0
work_for_cpu_fn+0x14/0x20
process_one_work+0x19e/0x470
worker_thread+0x1dc/0x4a0
kthread+0x125/0x140
ret_from_fork+0x25/0x30
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 6bf6b0aa3da84a3d9126919a94c49c0fb7ee2fb3 ]
If blk_mq_init_queue() returns an error, it gets assigned to
vblk->disk->queue. Then, when we call put_disk(), we end up calling
blk_put_queue() with the ERR_PTR, causing a bad dereference. Fix it by
only assigning to vblk->disk->queue on success.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a24fa22ce22ae302b3bf8f7008896d52d5d57b8d upstream.
There is no need to use xen_blkif_get()/xen_blkif_put() in the kthread
of xen-blkback. Thread stopping is synchronous and using the blkif
reference counting in the kthread will avoid to ever let the reference
count drop to zero at the end of an I/O running concurrent to
disconnecting and multiple rings.
Setting ring->xenblkd to NULL after stopping the kthread isn't needed
as the kthread does this already.
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Steven Haigh <netwiz@crc.id.au>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 71df1d7ccad1c36f7321d6b3b48f2ea42681c363 upstream.
The be structure must not be freed when freeing the blkif structure
isn't done. Otherwise a use-after-free of be when unmapping the ring
used for communicating with the frontend will occur in case of a
late call of xenblk_disconnect() (e.g. due to an I/O still active
when trying to disconnect).
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Steven Haigh <netwiz@crc.id.au>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2630628b2dbc3fc320aafaf84836119e4e3d62f1 upstream.
Apparently we now implicitly get definitions for BITS_PER_PAGE and
BITS_PER_PAGE_MASK from the pid_namespace.h
Instead of renaming our defines, I chose to define only if not yet
defined, but to double check the value if already defined.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d72e9a7a93e4f8e9e52491921d99e0c8aa89eb4e upstream.
The copy_page is optimized memcpy for page-alinged address. If it is
used with non-page aligned address, it can corrupt memory which means
system corruption. With zram, it can happen with
1. 64K architecture
2. partial IO
3. slub debug
Partial IO need to allocate a page and zram allocates it via kmalloc.
With slub debug, kmalloc(PAGE_SIZE) doesn't return page-size aligned
address. And finally, copy_page(mem, cmem) corrupts memory.
So, this patch changes it to memcpy.
Actuaully, we don't need to change zram_bvec_write part because zsmalloc
returns page-aligned address in case of PAGE_SIZE class but it's not
good to rely on the internal of zsmalloc.
Note:
When this patch is merged to stable, clear_page should be fixed, too.
Unfortunately, recent zram removes it by "same page merge" feature so
it's hard to backport this patch to -stable tree.
I will handle it when I receive the mail from stable tree maintainer to
merge this patch to backport.
Fixes: 42e99bd ("zram: optimize memory operations with clear_page()/copy_page()")
Link: http://lkml.kernel.org/r/1492042622-12074-2-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e02898b423802b1f3a3aaa7f16e896da069ba8f7 upstream.
loop_reread_partitions() needs to do I/O, but we just froze the queue,
so we end up waiting forever. This can easily be reproduced with losetup
-P. Fix it by moving the reread to after we unfreeze the queue.
Fixes: ecdd09597a57 ("block/loop: fix race between I/O and set_status")
Reported-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ecdd09597a57251323b0de50e3d45e69298c4a83 upstream.
Inside set_status, transfer need to setup again, so
we have to drain IO before the transition, otherwise
oops may be triggered like the following:
divide error: 0000 [#1] SMP KASAN
CPU: 0 PID: 2935 Comm: loop7 Not tainted 4.10.0-rc7+ #213
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
01/01/2011
task: ffff88006ba1e840 task.stack: ffff880067338000
RIP: 0010:transfer_xor+0x1d1/0x440 drivers/block/loop.c:110
RSP: 0018:ffff88006733f108 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff8800688d7000 RCX: 0000000000000059
RDX: 0000000000000000 RSI: 1ffff1000d743f43 RDI: ffff880068891c08
RBP: ffff88006733f160 R08: ffff8800688d7001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800688d7000
R13: ffff880067b7d000 R14: dffffc0000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88006d000000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006c17e0 CR3: 0000000066e3b000 CR4: 00000000001406f0
Call Trace:
lo_do_transfer drivers/block/loop.c:251 [inline]
lo_read_transfer drivers/block/loop.c:392 [inline]
do_req_filebacked drivers/block/loop.c:541 [inline]
loop_handle_cmd drivers/block/loop.c:1677 [inline]
loop_queue_work+0xda0/0x49b0 drivers/block/loop.c:1689
kthread_worker_fn+0x4c3/0xa30 kernel/kthread.c:630
kthread+0x326/0x3f0 kernel/kthread.c:227
ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430
Code: 03 83 e2 07 41 29 df 42 0f b6 04 30 4d 8d 44 24 01 38 d0 7f 08
84 c0 0f 85 62 02 00 00 44 89 f8 41 0f b6 48 ff 25 ff 01 00 00 99 <f7>
7d c8 48 63 d2 48 03 55 d0 48 89 d0 48 89 d7 48 c1 e8 03 83
RIP: transfer_xor+0x1d1/0x440 drivers/block/loop.c:110 RSP:
ffff88006733f108
---[ end trace 0166f7bd3b0c0933 ]---
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b4a567e8114327518c09f5632339a5954ab975a3 upstream.
->queue_rq() should return one of the BLK_MQ_RQ_QUEUE_* constants, not
an errno.
Fixes: f4aa4c7bbac6 ("block: loop: convert to per-device workqueue")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5c7e9ccd91b90d87029261f8856294ee51934cab upstream.
zram hot_add sysfs attribute is a very 'special' attribute - reading
from it creates a new uninitialized zram device. This file, by a
mistake, can be read by a 'normal' user at the moment, while only root
must be able to create a new zram device, therefore hot_add attribute
must have S_IRUSR mode, not S_IRUGO.
[akpm@linux-foundation.org: s/sence/sense/, reflow comment to use 80 cols]
Fixes: 6566d1a32bf72 ("zram: add dynamic device add/remove functionality")
Link: http://lkml.kernel.org/r/20161205155845.20129-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Steven Allen <steven@stebalien.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 529e71e16403830ae0d737a66c55c5f360f3576b upstream.
The zram hot removal code calls idr_remove() even when zram_remove()
returns an error (typically -EBUSY). This results in a leftover at the
device release, eventually leading to a crash when the module is
reloaded.
As described in the bug report below, the following procedure would
cause an Oops with zram:
- provision three zram devices via modprobe zram num_devices=3
- configure a size for each device
+ echo "1G" > /sys/block/$zram_name/disksize
- mkfs and mount zram0 only
- attempt to hot remove all three devices
+ echo 2 > /sys/class/zram-control/hot_remove
+ echo 1 > /sys/class/zram-control/hot_remove
+ echo 0 > /sys/class/zram-control/hot_remove
- zram0 removal fails with EBUSY, as expected
- unmount zram0
- try zram0 hot remove again
+ echo 0 > /sys/class/zram-control/hot_remove
- fails with ENODEV (unexpected)
- unload zram kernel module
+ completes successfully
- zram0 device node still exists
- attempt to mount /dev/zram0
+ mount command is killed
+ following BUG is encountered
BUG: unable to handle kernel paging request at ffffffffa0002ba0
IP: get_disk+0x16/0x50
Oops: 0000 [#1] SMP
CPU: 0 PID: 252 Comm: mount Not tainted 4.9.0-rc6 #176
Call Trace:
exact_lock+0xc/0x20
kobj_lookup+0xdc/0x160
get_gendisk+0x2f/0x110
__blkdev_get+0x10c/0x3c0
blkdev_get+0x19d/0x2e0
blkdev_open+0x56/0x70
do_dentry_open.isra.19+0x1ff/0x310
vfs_open+0x43/0x60
path_openat+0x2c9/0xf30
do_filp_open+0x79/0xd0
do_sys_open+0x114/0x1e0
SyS_open+0x19/0x20
entry_SYSCALL_64_fastpath+0x13/0x94
This patch adds the proper error check in hot_remove_store() not to call
idr_remove() unconditionally.
Fixes: 17ec4cd98578 ("zram: don't call idr_remove() from zram_remove()")
Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=1010970
Link: http://lkml.kernel.org/r/20161121132140.12683-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: David Disseldorp <ddiss@suse.de>
Reported-by: David Disseldorp <ddiss@suse.de>
Tested-by: David Disseldorp <ddiss@suse.de>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d8e9e5e80e882b4f90cba7edf1e6cb7376e52e54 upstream.
Don't pass a size larger than iov_len to kernel_sendmsg().
Otherwise it will cause a NULL pointer deref when kernel_sendmsg()
returns with rv < size.
DRBD as external module has been around in the kernel 2.4 days already.
We used to be compatible to 2.4 and very early 2.6 kernels,
we used to use
rv = sock_sendmsg(sock, &msg, iov.iov_len);
then later changed to
rv = kernel_sendmsg(sock, &msg, &iov, 1, size);
when we should have used
rv = kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
tcp_sendmsg() used to totally ignore the size parameter.
57be5bd ip: convert tcp_sendmsg() to iov_iter primitives
changes that, and exposes our long standing error.
Even with this error exposed, to trigger the bug, we would need to have
an environment (config or otherwise) causing us to not use sendpage()
for larger transfers, a failing connection, and have it fail "just at the
right time". Apparently that was unlikely enough for most, so this went
unnoticed for years.
Still, it is known to trigger at least some of these,
and suspected for the others:
[0] http://lists.linbit.com/pipermail/drbd-user/2016-July/023112.html
[1] http://lists.linbit.com/pipermail/drbd-dev/2016-March/003362.html
[2] https://forums.grsecurity.net/viewtopic.php?f=3&t=4546
[3] https://ubuntuforums.org/showthread.php?t=2336150
[4] http://e2.howsolveproblem.com/i/1175162/
This should go into 4.9,
and into all stable branches since and including v4.0,
which is the first to contain the exposing change.
It is correct for all stable branches older than that as well
(which contain the DRBD driver; which is 2.6.33 and up).
It requires a small "conflict" resolution for v4.4 and earlier, with v4.5
we dropped the comment block immediately preceding the kernel_sendmsg().
Fixes: b411b3637fa7 ("The DRBD driver")
Cc: viro@zeniv.linux.org.uk
Cc: christoph.lechleitner@iteg.at
Cc: wolfgang.glas@iteg.at
Reported-by: Christoph Lechleitner <christoph.lechleitner@iteg.at>
Tested-by: Christoph Lechleitner <christoph.lechleitner@iteg.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
[changed oneliner to be "obvious" without context; more verbose message]
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit da6ccaaa79caca4f38b540b651238f87215217a2 upstream.
Make the "Attempted send on closed socket" error messages generated in
nbd_request_handler() ratelimited.
When the nbd socket is shutdown, the nbd_request_handler() function emits
an error message for every request remaining in its queue. If the queue
is large, this will spam a large amount of messages to the log. There's
no need for a separate error message for each request, so this patch
ratelimits it.
In the specific case this was found, the system was virtual and the error
messages were logged to the serial port, which overwhelmed it.
Fixes: 4d48a542b427 ("nbd: fix I/O hang on disconnected nbds")
Signed-off-by: Dan Streetman <dan.streetman@canonical.com>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit dec63a4dec2d6d01346fd5d96062e67c0636852b upstream.
gcc-6.0 found an ancient bug in the paride driver, which had a
"module_param(verbose, bool, 0);" since before 2.6.12, but actually uses
it to accept '0', '1' or '2' as arguments:
drivers/block/paride/pd.c: In function 'pd_init_dev_parms':
drivers/block/paride/pd.c:298:29: warning: comparison of constant '1' with boolean expression is always false [-Wbool-compare]
#define DBMSG(msg) ((verbose>1)?(msg):NULL)
In 2012, Rusty did a cleanup patch that also changed the type of the
variable to 'bool', which introduced what is now a gcc warning.
This changes the type back to 'int' and adapts the module_param() line
instead, so it should work as documented in case anyone ever cares about
running the ancient driver with debugging.
Fixes: 90ab5ee94171 ("module_param: make bool parameters really bool (drivers & misc)")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Rusty Russell <rusty@rustcorp.com.au>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a7297a6a3a3322b054592e8e988981d2f5f29cc4 upstream.
Starting from commit e36f620428(block: split bios to max possible length),
block core starts to split bio in the middle of bvec.
Unfortunately loop dio/aio doesn't consider this situation, and
always treat 'iter.iov_offset' as zero. Then filesystem corruption
is observed.
This patch figures out the offset of the base bvevc via
'bio->bi_iter.bi_bvec_done' and fixes the issue by passing the offset
to iov iterator.
Fixes: e36f6204288088f (block: split bios to max possible length)
Cc: Keith Busch <keith.busch@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2224d879c7c0f85c14183ef82eb48bd875ceb599 upstream.
As of 5a60e87603c4c533492c515b7f62578189b03c9c, RBD object request
allocations are made via rbd_obj_request_create() with GFP_NOIO.
However, subsequent OSD request allocations in rbd_osd_req_create*()
use GFP_ATOMIC.
With heavy page cache usage (e.g. OSDs running on same host as krbd
client), rbd_osd_req_create() order-1 GFP_ATOMIC allocations have been
observed to fail, where direct reclaim would have allowed GFP_NOIO
allocations to succeed.
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Suggested-by: Neil Brown <neilb@suse.com>
Signed-off-by: David Disseldorp <ddiss@suse.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5e4298be45e83ecdffaabb370eea9396889b07f1 upstream.
Avoid that discard requests with size => PAGE_SIZE fail with
-EIO. Refuse discard requests if the discard size is not a
multiple of the page size.
Fixes: 2dbe54957636 ("brd: Refuse improperly aligned discard requests")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Jan Kara <jack@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Robert Elliot <elliott@hp.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 008e56d200225321371748d95908e6222436f06d upstream.
Fail all pending requests after surprise removal of a drive.
Signed-off-by: Vignesh Gunasekaran <vgunasekaran@micron.com>
Signed-off-by: Selvan Mani <smani@micron.com>
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit abb0ccd185c9e31847709b86192e6c815d1f57ad upstream.
Added timeout handler. Replaced blk_mq_end_request() with
blk_mq_complete_request() to avoid double completion of a request.
Signed-off-by: Selvan Mani <smani@micron.com>
Signed-off-by: Rajesh Kumar Sambandam <rsambandam@micron.com>
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit aae4a033868c496adae86fc6f9c3e0c405bbf360 upstream.
Allow device initialization to finish gracefully when it is in
FTL rebuild failure state. Also, recover device out of this state
after successfully secure erasing it.
Signed-off-by: Selvan Mani <smani@micron.com>
Signed-off-by: Vignesh Gunasekaran <vgunasekaran@micron.com>
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 51c6570eb922146470c2fe660c34585414679bd6 upstream.
Flush inflight IOs using fsync_bdev() when the device is safely
removed. Also, block further IOs in device open function.
Signed-off-by: Selvan Mani <smani@micron.com>
Signed-off-by: Rajesh Kumar Sambandam <rsambandam@micron.com>
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 59cf70e236c96594d9f1e065755d8fce9df5356b upstream.
When FTL rebuild is in progress, alloc_disk() initializes the disk
but device node will be created by add_disk() only after successful
completion of FTL rebuild. So, skip deletion of device node in
removal path when FTL rebuild is in progress.
Signed-off-by: Selvan Mani <smani@micron.com>
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5b7e0a8ac85e2dfd83830dc9e0b3554d153a37e3 upstream.
Print exact time when an internal command is interrupted.
Signed-off-by: Selvan Mani <smani@micron.com>
Signed-off-by: Rajesh Kumar Sambandam <rsambandam@micron.com>
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e35b94738a2f7caa12017f69ef385cb6b8028965 upstream.
Remove setting and clearing MTIP_PF_EH_ACTIVE_BIT flag in
mtip_handle_tfe() as they are redundant. Also avoid waking
up service thread from mtip_handle_tfe() because it is
already woken up in case of taskfile error.
Signed-off-by: Selvan Mani <smani@micron.com>
Signed-off-by: Rajesh Kumar Sambandam <rsambandam@micron.com>
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit cfc05bd31384c4898bf2437a4de5557f3cf9803a upstream.
Service thread does not detect the need for taskfile error hanlding. Fixed the
flag condition to process taskfile error.
Signed-off-by: Selvan Mani <smani@micron.com>
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d8a18d2d8f5de55666c6011ed175939d22c8e3d8 upstream.
Prevent standby immediate command from being issued in remove,
suspend and shutdown paths, while drive is in FTL rebuild process.
Signed-off-by: Selvan Mani <smani@micron.com>
Signed-off-by: Vignesh Gunasekaran <vgunasekaran@micron.com>
Signed-off-by: Asai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 17ec4cd985780a7e30aa45bb8f272237c12502a4 upstream.
The use of idr_remove() is forbidden in the callback functions of
idr_for_each(). It is therefore unsafe to call idr_remove in
zram_remove().
This patch moves the call to idr_remove() from zram_remove() to
hot_remove_store(). In the detroy_devices() path, idrs are removed by
idr_destroy(). This solves an use-after-free detected by KASan.
[akpm@linux-foundation.org: fix coding stype, per Sergey]
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d913897abace843bba20249f3190167f7895e9c3 upstream.
When we're using LZ4 multi compression streams for zram swap, we found
out page allocation failure message in system running test. That was
not only once, but a few(2 - 5 times per test). Also, some failure
cases were continually occurring to try allocation order 3.
In order to make parallel compression private data, we should call
kzalloc() with order 2/3 in runtime(lzo/lz4). But if there is no order
2/3 size memory to allocate in that time, page allocation fails. This
patch makes to use vmalloc() as fallback of kmalloc(), this prevents
page alloc failure warning.
After using this, we never found warning message in running test, also
It could reduce process startup latency about 60-120ms in each case.
For reference a call trace :
Binder_1: page allocation failure: order:3, mode:0x10c0d0
CPU: 0 PID: 424 Comm: Binder_1 Tainted: GW 3.10.49-perf-g991d02b-dirty #20
Call trace:
dump_backtrace+0x0/0x270
show_stack+0x10/0x1c
dump_stack+0x1c/0x28
warn_alloc_failed+0xfc/0x11c
__alloc_pages_nodemask+0x724/0x7f0
__get_free_pages+0x14/0x5c
kmalloc_order_trace+0x38/0xd8
zcomp_lz4_create+0x2c/0x38
zcomp_strm_alloc+0x34/0x78
zcomp_strm_multi_find+0x124/0x1ec
zcomp_strm_find+0xc/0x18
zram_bvec_rw+0x2fc/0x780
zram_make_request+0x25c/0x2d4
generic_make_request+0x80/0xbc
submit_bio+0xa4/0x15c
__swap_writepage+0x218/0x230
swap_writepage+0x3c/0x4c
shrink_page_list+0x51c/0x8d0
shrink_inactive_list+0x3f8/0x60c
shrink_lruvec+0x33c/0x4cc
shrink_zone+0x3c/0x100
try_to_free_pages+0x2b8/0x54c
__alloc_pages_nodemask+0x514/0x7f0
__get_free_pages+0x14/0x5c
proc_info_read+0x50/0xe4
vfs_read+0xa0/0x12c
SyS_read+0x44/0x74
DMA: 3397*4kB (MC) 26*8kB (RC) 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB
0*512kB 0*1024kB 0*2048kB 0*4096kB = 13796kB
[minchan@kernel.org: change vmalloc gfp and adding comment about gfp]
[sergey.senozhatsky@gmail.com: tweak comments and styles]
Signed-off-by: Kyeongdon Kim <kyeongdon.kim@lge.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3d5fe03a3ea013060ebba2a811aeb0f23f56aefa upstream.
We can end up allocating a new compression stream with GFP_KERNEL from
within the IO path, which may result is nested (recursive) IO
operations. That can introduce problems if the IO path in question is a
reclaimer, holding some locks that will deadlock nested IOs.
Allocate streams and working memory using GFP_NOIO flag, forbidding
recursive IO and FS operations.
An example:
inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
git/20158 [HC0[0]:SC0[0]:HE1:SE1] takes:
(jbd2_handle){+.+.?.}, at: start_this_handle+0x4ca/0x555
{IN-RECLAIM_FS-W} state was registered at:
__lock_acquire+0x8da/0x117b
lock_acquire+0x10c/0x1a7
start_this_handle+0x52d/0x555
jbd2__journal_start+0xb4/0x237
__ext4_journal_start_sb+0x108/0x17e
ext4_dirty_inode+0x32/0x61
__mark_inode_dirty+0x16b/0x60c
iput+0x11e/0x274
__dentry_kill+0x148/0x1b8
shrink_dentry_list+0x274/0x44a
prune_dcache_sb+0x4a/0x55
super_cache_scan+0xfc/0x176
shrink_slab.part.14.constprop.25+0x2a2/0x4d3
shrink_zone+0x74/0x140
kswapd+0x6b7/0x930
kthread+0x107/0x10f
ret_from_fork+0x3f/0x70
irq event stamp: 138297
hardirqs last enabled at (138297): debug_check_no_locks_freed+0x113/0x12f
hardirqs last disabled at (138296): debug_check_no_locks_freed+0x33/0x12f
softirqs last enabled at (137818): __do_softirq+0x2d3/0x3e9
softirqs last disabled at (137813): irq_exit+0x41/0x95
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(jbd2_handle);
<Interrupt>
lock(jbd2_handle);
*** DEADLOCK ***
5 locks held by git/20158:
#0: (sb_writers#7){.+.+.+}, at: [<ffffffff81155411>] mnt_want_write+0x24/0x4b
#1: (&type->i_mutex_dir_key#2/1){+.+.+.}, at: [<ffffffff81145087>] lock_rename+0xd9/0xe3
#2: (&sb->s_type->i_mutex_key#11){+.+.+.}, at: [<ffffffff8114f8e2>] lock_two_nondirectories+0x3f/0x6b
#3: (&sb->s_type->i_mutex_key#11/4){+.+.+.}, at: [<ffffffff8114f909>] lock_two_nondirectories+0x66/0x6b
#4: (jbd2_handle){+.+.?.}, at: [<ffffffff811e31db>] start_this_handle+0x4ca/0x555
stack backtrace:
CPU: 2 PID: 20158 Comm: git Not tainted 4.1.0-rc7-next-20150615-dbg-00016-g8bdf555-dirty #211
Call Trace:
dump_stack+0x4c/0x6e
mark_lock+0x384/0x56d
mark_held_locks+0x5f/0x76
lockdep_trace_alloc+0xb2/0xb5
kmem_cache_alloc_trace+0x32/0x1e2
zcomp_strm_alloc+0x25/0x73 [zram]
zcomp_strm_multi_find+0xe7/0x173 [zram]
zcomp_strm_find+0xc/0xe [zram]
zram_bvec_rw+0x2ca/0x7e0 [zram]
zram_make_request+0x1fa/0x301 [zram]
generic_make_request+0x9c/0xdb
submit_bio+0xf7/0x120
ext4_io_submit+0x2e/0x43
ext4_bio_write_page+0x1b7/0x300
mpage_submit_page+0x60/0x77
mpage_map_and_submit_buffers+0x10f/0x21d
ext4_writepages+0xc8c/0xe1b
do_writepages+0x23/0x2c
__filemap_fdatawrite_range+0x84/0x8b
filemap_flush+0x1c/0x1e
ext4_alloc_da_blocks+0xb8/0x117
ext4_rename+0x132/0x6dc
? mark_held_locks+0x5f/0x76
ext4_rename2+0x29/0x2b
vfs_rename+0x540/0x636
SyS_renameat2+0x359/0x44d
SyS_rename+0x1e/0x20
entry_SYSCALL_64_fastpath+0x12/0x6f
[minchan@kernel.org: add stable mark]
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Kyeongdon Kim <kyeongdon.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If null_blk is run in NULL_IRQ_TIMER mode and with queue_mode NULL_Q_RQ,
we need to restart the queue from the hrtimer interrupt. We can't
directly invoke the request_fn from that context, so punt the queue run
to async kblockd context.
Tested-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Jens Axboe <axboe@fb.com>
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Pull block layer fixes from Jens Axboe:
"Three small fixes for 4.4 final. Specifically:
- The segment issue fix from Junichi, where the old IO path does a
bio limit split before potentially bouncing the pages. We need to
do that in the right order, to ensure that limitations are met.
- A NVMe surprise removal IO hang fix from Keith.
- A use-after-free in null_blk, introduced by a previous patch in
this series. From Mike Krinkin"
* 'for-linus' of git://git.kernel.dk/linux-block:
null_blk: fix use-after-free error
block: ensure to split after potentially bouncing a bio
NVMe: IO ending fixes on surprise removal
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blk_end_request_all may free request, so we need to save
request_queue pointer before blk_end_request_all call.
The problem was introduced in commit cf8ecc5a8455266f8d51
("null_blk: guarantee device restart in all irq modes")
and causes general protection fault with slab poisoning
enabled.
Fixes: cf8ecc5a8455266f8d51 ("null_blk: guarantee device
restart in all irq modes")
Signed-off-by: Mike Krinkin <krinkin.m.u@gmail.com>
Reviewed-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen bug fixes from David Vrabel:
- XSA-155 security fixes to backend drivers.
- XSA-157 security fixes to pciback.
* tag 'for-linus-4.4-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen-pciback: fix up cleanup path when alloc fails
xen/pciback: Don't allow MSI-X ops if PCI_COMMAND_MEMORY is not set.
xen/pciback: For XEN_PCI_OP_disable_msi[|x] only disable if device has MSI(X) enabled.
xen/pciback: Do not install an IRQ handler for MSI interrupts.
xen/pciback: Return error on XEN_PCI_OP_enable_msix when device has MSI or MSI-X enabled
xen/pciback: Return error on XEN_PCI_OP_enable_msi when device has MSI or MSI-X enabled
xen/pciback: Save xen_pci_op commands before processing it
xen-scsiback: safely copy requests
xen-blkback: read from indirect descriptors only once
xen-blkback: only read request operation from shared ring once
xen-netback: use RING_COPY_REQUEST() throughout
xen-netback: don't use last request to determine minimum Tx credit
xen: Add RING_COPY_REQUEST()
xen/x86/pvh: Use HVM's flush_tlb_others op
xen: Resume PMU from non-atomic context
xen/events/fifo: Consume unprocessed events when a CPU dies
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Since indirect descriptors are in memory shared with the frontend, the
frontend could alter the first_sect and last_sect values after they have
been validated but before they are recorded in the request. This may
result in I/O requests that overflow the foreign page, possibly
overwriting local pages when the I/O request is executed.
When parsing indirect descriptors, only read first_sect and last_sect
once.
This is part of XSA155.
CC: stable@vger.kernel.org
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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A compiler may load a switch statement value multiple times, which could
be bad when the value is in memory shared with the frontend.
When converting a non-native request to a native one, ensure that
src->operation is only loaded once by using READ_ONCE().
This is part of XSA155.
CC: stable@vger.kernel.org
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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Pull block layer fixes from Jens Axboe:
"A set of fixes for the current series. This contains:
- A bunch of fixes for lightnvm, should be the last round for this
series. From Matias and Wenwei.
- A writeback detach inode fix from Ilya, also marked for stable.
- A block (though it says SCSI) fix for an OOPS in SCSI runtime power
management.
- Module init error path fixes for null_blk from Minfei"
* 'for-linus' of git://git.kernel.dk/linux-block:
null_blk: Fix error path in module initialization
lightnvm: do not compile in debugging by default
lightnvm: prevent gennvm module unload on use
lightnvm: fix media mgr registration
lightnvm: replace req queue with nvmdev for lld
lightnvm: comments on constants
lightnvm: check mm before use
lightnvm: refactor spin_unlock in gennvm_get_blk
lightnvm: put blks when luns configure failed
lightnvm: use flags in rrpc_get_blk
block: detach bdev inode from its wb in __blkdev_put()
SCSI: Fix NULL pointer dereference in runtime PM
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Module couldn't release resource properly during the initialization. To
fix this issue, we will clean up the proper resource before returning.
Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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In the case where a request queue is passed to the low lever lightnvm
device drive integration, the device driver might pass its admin
commands through another queue. Instead pass nvm_dev, and let the
low level drive the appropriate queue.
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
Pull Ceph fix from Sage Weil:
"This addresses a refcounting bug that leads to a use-after-free"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
rbd: don't put snap_context twice in rbd_queue_workfn()
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Commit 4e752f0ab0e8 ("rbd: access snapshot context and mapping size
safely") moved ceph_get_snap_context() out of rbd_img_request_create()
and into rbd_queue_workfn(), adding a ceph_put_snap_context() to the
error path in rbd_queue_workfn(). However, rbd_img_request_create()
consumes a ref on snapc, so calling ceph_put_snap_context() after
a successful rbd_img_request_create() leads to an extra put. Fix it.
Cc: stable@vger.kernel.org # 3.18+
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Josh Durgin <jdurgin@redhat.com>
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This commit at least doubles the maximum value for
completion_nsec. This helps in special cases where one wants/needs to
emulate an extremely slow I/O (for example to spot bugs).
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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In single-queue (block layer) mode,the function null_rq_prep_fn stops
the device if alloc_cmd fails. Then, once stopped, the device must be
restarted on the next command completion, so that the request(s) for
which alloc_cmd failed can be requeued. Otherwise the device hangs.
Unfortunately, device restart is currently performed only for delayed
completions, i.e., in irqmode==2. This fact causes hangs, for the
above reasons, with the other irqmodes in combination with single-queue
block layer.
This commits addresses this issue by making sure that, if stopped, the
device is properly restarted for all irqmodes on completions.
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna AVanzini <avanzini@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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For the Timer IRQ mode (i.e., when command completions are delayed),
there is one timer for each CPU. Each of these timers
. has a completion queue associated with it, containing all the
command completions to be executed when the timer fires;
. is set, and a new completion-to-execute is inserted into its
completion queue, every time the dispatch code for a new command
happens to be executed on the CPU related to the timer.
This implies that, if the dispatch of a new command happens to be
executed on a CPU whose timer has already been set, but has not yet
fired, then the timer is set again, to the completion time of the
newly arrived command. When the timer eventually fires, all its queued
completions are executed.
This way of handling delayed command completions entails the following
problem: if more than one command completion is inserted into the
queue of a timer before the timer fires, then the expiration time for
the timer is moved forward every time each of these completions is
enqueued. As a consequence, only the last completion enqueued enjoys a
correct execution time, while all previous completions are unjustly
delayed until the last completion is executed (and at that time they
are executed all together).
Specifically, if all the above completions are enqueued almost at the
same time, then the problem is negligible. On the opposite end, if
every completion is enqueued a while after the previous completion was
enqueued (in the extreme case, it is enqueued only right before the
timer would have expired), then every enqueued completion, except for
the last one, experiences an inflated delay, proportional to the number
of completions enqueued after it. In the end, commands, and thus I/O
requests, may be completed at an arbitrarily lower rate than the
desired one.
This commit addresses this issue by replacing per-CPU timers with
per-command timers, i.e., by associating an individual timer with each
command.
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Arianna Avanzini <avanzini@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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