Step 1 - don't reinintialize ->msg_iter on each iteration.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and keep ->msg_iter through the loop
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

ktime_set(S,N) was required for the timespec storage type and is still
useful for situations where a Seconds and Nanoseconds part of a time value
needs to be converted. For anything where the Seconds argument is 0, this
is pointless and can be replaced with a simple assignment.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.
Requested-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/block/rbd.c: In function ‘rbd_watch_cb’:
drivers/block/rbd.c:3690:5: error: ‘struct_v’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/block/rbd.c:3759:5: note: ‘struct_v’ was declared here
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>

While doing stress tests we noticed that we'd get a lot of dmesg spam if
we suddenly disconnected the nbd device out of band.  Rate limit the
messages in the io path in order to deal with this.
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

If an app exits before running NBD_DO_IT but after adding sockets we can
end up not being allowed to do a new nbd device.  Fix this by making
NBD_CLEAR_SOCK reset the setup_task.
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

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: 6566d1a3 ("zram: add dynamic device add/remove functionality")
Link: http://lkml.kernel.org/r/20161205155845.20129-1-sergey.senozhatsky@gmail.comSigned-off-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: NSteven Allen <steven@stebalien.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>    [4.2+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have this:

ERROR: "__aeabi_ldivmod" [drivers/block/nbd.ko] undefined!
ERROR: "__divdi3" [drivers/block/nbd.ko] undefined!
nbd.c:(.text+0x247c72): undefined reference to `__divdi3'

due to a recent commit, that did 64-bit division. Use the proper
divider function so that 32-bit compiles don't break.

Fixes: ef77b515 ("nbd: use loff_t for blocksize and nbd_set_size args")
Signed-off-by: NJens Axboe <axboe@fb.com>

If we have large devices (say like the 40t drive I was trying to test with) we
will end up overflowing the int arguments to nbd_set_size and not get the right
size for our device.  Fix this by using loff_t everywhere so I don't have to
think about this again.  Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Install the callbacks via the state machine with multi instance support and let
the core invoke the callbacks on the already online CPUs.

[bigeasy: wire up the multi instance stuff]
Signed-off-by: NAnna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: rt@linutronix.de
Cc: Nitin Gupta <ngupta@vflare.org>
Link: http://lkml.kernel.org/r/20161126231350.10321-19-bigeasy@linutronix.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Fix bug https://bugzilla.kernel.org/show_bug.cgi?id=188531. In function
mtip_block_initialize(), variable rv takes the return value, and its
value should be negative on errors. rv is initialized as 0 and is not
reset when the call to ida_pre_get() fails. So 0 may be returned.
The return value 0 indicates that there is no error, which may be
inconsistent with the execution status. This patch fixes the bug by
explicitly assigning -ENOMEM to rv on the branch that ida_pre_get()
fails.
Signed-off-by: NPan Bian <bianpan2016@163.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

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: 17ec4cd9 ("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.deSigned-off-by: NTakashi Iwai <tiwai@suse.de>
Reviewed-by: NDavid Disseldorp <ddiss@suse.de>
Reported-by: NDavid Disseldorp <ddiss@suse.de>
Tested-by: NDavid Disseldorp <ddiss@suse.de>
Acked-by: NMinchan Kim <minchan@kernel.org>
Acked-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: <stable@vger.kernel.org>    [4.4+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Multiple paths don't set it properly, ensure that we do.

Fixes: 9561a7ad ("nbd: add multi-connection support")
Signed-off-by: NJens Axboe <axboe@fb.com>

NBD can become contended on its single connection.  We have to serialize all
writes and we can only process one read response at a time.  Fix this by
allowing userspace to provide multiple connections to a single nbd device.  This
coupled with block-mq drastically increases performance in multi-process cases.
Thanks,
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

For a non-cloned bio, bio_add_page() only returns failure when
the io vec table is full, but in that case, bio->bi_vcnt can't
be zero at all.

So remove the impossible failure handling.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Some drivers often use external bvec table, so introduce
this helper for this case. It is always safe to access the
bio->bi_io_vec in this way for this case.

After converting to this usage, it will becomes a bit easier
to evaluate the remaining direct access to bio->bi_io_vec,
so it can help to prepare for the following multipage bvec
support.
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>

Fixed up the new O_DIRECT cases.
Signed-off-by: NJens Axboe <axboe@fb.com>

This driver is both orphaned, and not really useful anymore. Mark
it as such, and remove it in a future kernel after a release or
two.
Signed-off-by: NJens Axboe <axboe@fb.com>

Drop duplicate header scatterlist.h from skd_main.c.
Signed-off-by: NGeliang Tang <geliangtang@gmail.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

For writes, we can get a completion in while we're still iterating
the request and bio chain. If that happens, we're reading freed
memory and we can crash.

Break out after the last segment and avoid having the iterator
read freed memory.
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

If CONFIG_NVM is disabled, loading null_block module with use_lightnvm=1
fails. But there are no messages and documents related to the failure.

Add the appropriate error message.
Signed-off-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>

Massaged the text a bit.
Signed-off-by: NJens Axboe <axboe@fb.com>

->queue_rq() should return one of the BLK_MQ_RQ_QUEUE_* constants, not
an errno.

f4aa4c7b ("block: loop: convert to per-device workqueue")
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@fb.com>

aoeblk contains some mysterious code, that wants to elevate the bio
vec page counts while it's under IO. That is not needed, it's
fragile, and it's causing kernel oopses for some.
Reported-by: NTested-by: Don Koch <kochd@us.ibm.com>
Tested-by: NTested-by: Don Koch <kochd@us.ibm.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

There is no need to call kfree() if memdup_user() fails, as no memory
was allocated and the error in the error-valued pointer should be returned.
Signed-off-by: NSachin Shukla <sachin.s5@samsung.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Building with W=1 shows a harmless warning for the skd driver:

drivers/block/skd_main.c:2959:1: error: ‘static’ is not at beginning of declaration [-Werror=old-style-declaration]

This changes the prototype to the expected formatting.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

As reported by gcc -Wmaybe-uninitialized, the cleanup path for
skd_acquire_msix tries to free the already allocated msi-x vectors
in reverse order, but the index variable may not have been
used yet:

drivers/block/skd_main.c: In function ‘skd_acquire_irq’:
drivers/block/skd_main.c:3890:8: error: ‘i’ may be used uninitialized in this function [-Werror=maybe-uninitialized]

This changes the failure path to skip releasing the interrupts
if we have not started requesting them yet.

Fixes: 180b0ae7 ("skd: use pci_alloc_irq_vectors")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

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.
 57be5bda 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: b411b363 ("The DRBD driver")
Cc: <stable@vger.kernel.org> # 2.6.33.x-
Cc: viro@zeniv.linux.org.uk
Cc: christoph.lechleitner@iteg.at
Cc: wolfgang.glas@iteg.at
Reported-by: NChristoph Lechleitner <christoph.lechleitner@iteg.at>
Tested-by: NChristoph Lechleitner <christoph.lechleitner@iteg.at>
Signed-off-by: NRichard Weinberger <richard@nod.at>
[changed oneliner to be "obvious" without context; more verbose message]
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

For small buffers we may use %*ph[N] specifier, for the bigger blocks
print_hex_dump() call.

Cc: Don Brace <don.brace@microsemi.com>
Cc: esc.storagedev@microsemi.com
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: NDon Brace <don.brace@microsemi.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Replace custom approach by %*ph specifier to dump small buffers in hex format.

Unfortunately we can't use print_hex_dump_bytes() here since tha gap is
present, though one familiar with the code may change this.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Switch the skd driver to use pci_alloc_irq_vectors.  We need to two calls to
pci_alloc_irq_vectors as skd only supports multiple MSI-X vectors, but not
multiple MSI vectors.

Otherwise this cleans up a lot of cruft and allows to a lot more common code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Hi Peter, hi Jens,

I've been looking over the multi page bio vec work again recently, and
one of the stumbling blocks is raw biovec access in the pktcdvd.

The first issue is that it directly sets up the page and offset pointers
in the biovec just before calling bio_add_page.  As bio_add_page already
does the setup it's trivial to just switch it to stack variables for the
arguments.

The second issue is the copy code in pkt_make_local_copy, which
effectively is an opencoded version of bio_copy_data except that it
skips pages that already are the same in the ѕource and destination.
But we look at the only calleer we just set up the bio using bio_add_page
to point exactly to the page array that pkt_make_local_copy compares,
so the pages will always be the same and we can just remove this function.

Note that all this is done based on code inspection, I don't have any
packet writing hardware myself.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of some reads from int to unsigned,
but these cases have been wrong before: negative values are not allowed
for the modified cases.

Cc: konrad.wilk@oracle.com
Cc: roger.pau@citrix.com
Signed-off-by: NJuergen Gross <jgross@suse.com>
Acked-by: NDavid Vrabel <david.vrabel@citrix.com>

Use xenbus_read_unsigned() instead of xenbus_scanf() when possible.
This requires to change the type of one read from int to unsigned,
but this case has been wrong before: negative values are not allowed
for the modified case.

Cc: konrad.wilk@oracle.com
Cc: roger.pau@citrix.com
Signed-off-by: NJuergen Gross <jgross@suse.com>
Acked-by: NDavid Vrabel <david.vrabel@citrix.com>

'blk_mq_alloc_request()' returns an error pointer in case of error, not
NULL. So test it with IS_ERR.

Fixes: 	fd8383fd ("nbd: convert to blkmq")
Signed-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: NJens Axboe <axboe@fb.com>

Most blk_mq_requeue_request() and blk_mq_add_to_requeue_list() calls
are followed by kicking the requeue list. Hence add an argument to
these two functions that allows to kick the requeue list. This was
proposed by Christoph Hellwig.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NJens Axboe <axboe@fb.com>

Since blk_mq_requeue_work() starts stopped queues and since
execution of this function can be scheduled after a queue has
been stopped it is not possible to stop queues without using
an additional state variable to track whether or not the queue
has been stopped. Hence modify blk_mq_requeue_work() such that it
does not start stopped queues. My conclusion after a review of
the blk_mq_stop_hw_queues() and blk_mq_{delay_,}kick_requeue_list()
callers is as follows:
* In the dm driver starting and stopping queues should only happen
  if __dm_suspend() or __dm_resume() is called and not if the
  requeue list is processed.
* In the SCSI core queue stopping and starting should only be
  performed by the scsi_internal_device_block() and
  scsi_internal_device_unblock() functions but not by any other
  function. Although the blk_mq_stop_hw_queue() call in
  scsi_queue_rq() may help to reduce CPU load if a LLD queue is
  full, figuring out whether or not a queue should be restarted
  when requeueing a command would require to introduce additional
  locking in scsi_mq_requeue_cmd() to avoid a race with
  scsi_internal_device_block(). Avoid this complexity by removing
  the blk_mq_stop_hw_queue() call from scsi_queue_rq().
* In the NVMe core only the functions that call
  blk_mq_start_stopped_hw_queues() explicitly should start stopped
  queues.
* A blk_mq_start_stopped_hwqueues() call must be added in the
  xen-blkfront driver in its blkif_recover() function.
Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: James Bottomley <jejb@linux.vnet.ibm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly.  Where applicable this also drops usage of the
bio_set_op_attrs wrapper.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Noidle should be the default for writes as seen by all the compounds
definitions in fs.h using it.  In fact only direct I/O really should
be using NODILE, so turn the whole flag around to get the defaults
right, which will make our life much easier especially onces the
WRITE_* defines go away.

This assumes all the existing "raw" users of REQ_SYNC for writes
want noidle behavior, which seems to be spot on from a quick audit.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>