Constify all instances of blk_mq_ops, as they are never modified.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Use automatic IRQ affinity assignment in the virtio layer if available,
and build the blk-mq queues based on it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Add a struct irq_affinity pointer to the find_vqs methods, which if set
is used to tell the PCI layer to create the MSI-X vectors for our I/O
virtqueues with the proper affinity from the start.  Compared to after
the fact affinity hints this gives us an instantly working setup and
allows to allocate the irq descritors node-local and avoid interconnect
traffic.  Last but not least this will allow blk-mq queues are created
based on the interrupt affinity for storage drivers.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Instead of keeping two levels of indirection for requests types, fold it
all into the operations.  The little caveat here is that previously
cmd_type only applied to struct request, while the request and bio op
fields were set to plain REQ_OP_READ/WRITE even for passthrough
operations.

Instead this patch adds new REQ_OP_* for SCSI passthrough and driver
private requests, althought it has to add two for each so that we
can communicate the data in/out nature of the request.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

The SCSI passthrough idea was a a bad idea to start with (guess who came
up with it?), and has been removed from the virtio 1.O spec, and is not
enabled by defauly by any host I know of.  Add a separate config option
for it so that we don't need to enable it for most setups.  That way
any bugs related to it (like the one recently fixed for vmapped stacks)
do not affect other users, and the size of the virtblk_req structure
also shrinks significantly.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

We can simply use blk_mq_rq_from_pdu to get back at the request at
I/O completion time.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

And require all drivers that want to support BLOCK_PC to allocate it
as the first thing of their private data.  To support this the legacy
IDE and BSG code is switched to set cmd_size on their queues to let
the block layer allocate the additional space.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Since we need to change the implementation, stop exposing internals.

Provide kref_read() to read the current reference count; typically
used for debug messages.

Kills two anti-patterns:

	atomic_read(&kref->refcount)
	kref->refcount.counter
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

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: NOmar Sandoval <osandov@fb.com>
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Most users of BLOCK_PC requests allocate the sense buffer on the stack,
so to avoid DMA to the stack copy them to a field in the heap allocated
virtblk_req structure.  Without that any attempt at SCSI passthrough I/O,
including the SG_IO ioctl from userspace will crash the kernel.  Note that
this includes running tools like hdparm even when the host does not have
SCSI passthrough enabled.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: NJens Axboe <axboe@fb.com>

The local variable "err" will be set to an appropriate value
by a following statement.
Thus omit the explicit initialisation at the beginning.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Multiplications for the size determination of memory allocations
indicated that array data structures should be processed.
Thus use the corresponding function "kmalloc_array".

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

All drivers use the default, so provide an inline version of it.  If we
ever need other queue mapping we can add an optional method back,
although supporting will also require major changes to the queue setup
code.

This provides better code generation, and better debugability as well.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NKeith Busch <keith.busch@intel.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

We do a lot of memory allocation in function init_vq, and don't handle
the allocation failure properly. Then this function will return 0,
although initialization fails due to lacking memory. At that moment,
kernel will panic in guest machine, if virtio is used to drive disk.

To fix this bug, we should take care of allocation failure, and return
correct value to let caller know what happen.
Tested-by: NChao Fan <fanc.fnst@cn.fujitsu.com>
Signed-off-by: NMinfei Huang <mnghuan@gmail.com>
Signed-off-by: NMinfei Huang <minfei.hmf@alibaba-inc.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

blk_get_request is used for BLOCK_PC and similar passthrough requests.
Currently we always need to call blk_rq_set_block_pc or an open coded
version of it to allow appending bios using the request mapping helpers
later on, which is a somewhat awkward API.  Instead move the
initialization part of blk_rq_set_block_pc into blk_get_request, so that
we always have a safe to use request.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

Similar to how SCSI and NVMe prepare passthrough requests.  This avoids
poking into request internals too much.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

For block drivers that specify a parent device, convert them to use
device_add_disk().

This conversion was done with the following semantic patch:

    @@
    struct gendisk *disk;
    expression E;
    @@

    - disk->driverfs_dev = E;
    ...
    - add_disk(disk);
    + device_add_disk(E, disk);

    @@
    struct gendisk *disk;
    expression E1, E2;
    @@

    - disk->driverfs_dev = E1;
    ...
    E2 = disk;
    ...
    - add_disk(E2);
    + device_add_disk(E1, E2);

...plus some manual fixups for a few missed conversions.

Cc: Jens Axboe <axboe@fb.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

This adds a REQ_OP_FLUSH operation that is sent to request_fn
based drivers by the block layer's flush code, instead of
sending requests with the request->cmd_flags REQ_FLUSH bit set.
Signed-off-by: NMike Christie <mchristi@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

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

Latest virtio spec says the feature bit name is VIRTIO_BLK_F_FLUSH,
VIRTIO_BLK_F_WCE is the legacy name.  virtio blk header says exactly the
reverse - fix that and update driver code to match.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

blk_mq_complete_request may be a no-op if the request has already
been completed by others means (e.g. a timeout or cancellation), but
currently drivers have to set rq->errors before calling
blk_mq_complete_request, which might leave us with the wrong error value.

Add an error parameter to blk_mq_complete_request so that we can
defer setting rq->errors until we known we won the race to complete the
request.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

This will allow up to DISK_MAX_PARTS (256) partitions, with for example
GPT in the guest. Otherwise, the partition scan code will only discover
the first 15 partitions.
Signed-off-by: NFam Zheng <famz@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

VIRTIO_BLK_F_CONFIG_WCE is important in order to achieve good performance
(up to 2x, though more realistically +30-40%) in latency-bound workloads.
However, it was removed by mistake together with VIRTIO_BLK_F_FLUSH.

It will be restored in the next revision of the virtio 1.0 standard, so
do the same in Linux.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

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

The current string_get_size() overflows when the device size goes over
2^64 bytes because the string helper routine computes the suffix from
the size in bytes.  However, the entirety of Linux thinks in terms of
blocks, not bytes, so this will artificially induce an overflow on very
large devices.  Fix this by making the function string_get_size() take
blocks and the block size instead of bytes.  This should allow us to
keep working until the current SCSI standard overflows.

Also fix virtio_blk and mmc (both of which were also artificially
multiplying by the block size to pass a byte side to string_get_size()).

The mathematics of this is pretty simple:  we're taking a product of
size in blocks (S) and block size (B) and trying to re-express this in
exponential form: S*B = R*N^E (where N, the exponent is either 1000 or
1024) and R < N.  Mathematically, S = RS*N^ES and B=RB*N^EB, so if RS*RB
< N it's easy to see that S*B = RS*RB*N^(ES+EB).  However, if RS*BS > N,
we can see that this can be re-expressed as RS*BS = R*N (where R =
RS*BS/N < N) so the whole exponent becomes R*N^(ES+EB+1)

[jejb: fix incorrect 32 bit do_div spotted by kbuild test robot <fengguang.wu@intel.com>]
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Most of our code has
struct foo {
}

Fix two instances where blk is inconsistent.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Some devices might not implement config space access
(e.g. remoteproc used not to - before 3.9).
virtio/blk needs config space access so make it
fail gracefully if not there.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Check IS_ERR_OR_NULL(return value) instead of just return value.
Signed-off-by: NMing Lei <ming.lei@canonical.com>

Reduced to IS_ERR() by me, we never return NULL.
Signed-off-by: NJens Axboe <axboe@fb.com>

Core activates this bit automatically now,
drop it from drivers that set it explicitly.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

If a device appears while module is being removed,
driver will get a callback after we've given up
on the major number.

In theory this means this major number can get reused
by something else, resulting in a conflict.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

It's never declared so no need to make it extern.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>

Based on patch by Cornelia Huck.

Note: for consistency, and to avoid sparse errors,
      convert all fields, even those no longer in use
      for virtio v1.0.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

If a device appears while module is being removed,
driver will get a callback after we've given up
on the major number.

In theory this means this major number can get reused
by something else, resulting in a conflict.

To fix, cleanup in reverse order of initialization.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Since we have the notion of a 'last' request in a chain, we can use
this to have the hardware optimize the issuing of requests. Add
a list_head parameter to queue_rq that the driver can use to
temporarily store hw commands for issue when 'last' is true. If we
are doing a chain of requests, pass in a NULL list for the first
request to force issue of that immediately, then batch the remainder
for deferred issue until the last request has been sent.

Instead of adding yet another argument to the hot ->queue_rq path,
encapsulate the passed arguments in a blk_mq_queue_data structure.
This is passed as a constant, and has been tested as faster than
passing 4 (or even 3) args through ->queue_rq. Update drivers for
the new ->queue_rq() prototype. There are no functional changes
in this patch for drivers - if they don't use the passed in list,
then they will just queue requests individually like before.
Signed-off-by: NJens Axboe <axboe@fb.com>

virtio spec requires drivers to set DRIVER_OK before using VQs.
This is set automatically after restore returns, virtio block violated
this rule on restore by restarting queues, which might in theory
cause the VQ to be used directly within restore.

To fix, call virtio_device_ready before using starting queues.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

virtio spec requires drivers to set DRIVER_OK before using VQs.
This is set automatically after probe returns, virtio block violated this
rule by calling add_disk, which causes the VQ to be used directly within
probe.

To fix, call virtio_device_ready before using VQs.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

config_mutex served two purposes: prevent multiple concurrent config
change handlers, and synchronize access to config_enable flag.

Since commit dbf2576e
    workqueue: make all workqueues non-reentrant
all workqueues are non-reentrant, and config_enable
is now gone.

Get rid of the unnecessary lock.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Now that virtio core ensures config changes don't
arrive during probing, drop config_enable flag
in virtio blk.
On removal, flush is now sufficient to guarantee that
no change work is queued.

This help simplify the driver, and will allow
setting DRIVER_OK earlier without losing config
change notifications.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Now that we've changed the driver API on the submission side use the
opportunity to fix up the name on the completion side to fit into the
general scheme.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>

When we call blk_mq_start_request from the core blk-mq code before calling into
->queue_rq there is a racy window where the timeout handler can hit before we've
fully set up the driver specific part of the command.

Move the call to blk_mq_start_request into the driver so the driver can start
the request only once it is fully set up.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@fb.com>