Remove the tagged argument from scsi_adjust_queue_depth, and just let it
handle the queue depth.  For most drivers those two are fairly separate,
given that most modern drivers don't care about the SCSI "tagged" status
of a command at all, and many old drivers allow queuing of multiple
untagged commands in the driver.

Instead we start out with the ->simple_tags flag set before calling
->slave_configure, which is how all drivers actually looking at
->simple_tags except for one worke anyway.  The one other case looks
broken, but I've kept the behavior as-is for now.

Except for that we only change ->simple_tags from the ->change_queue_type,
and when rejecting a tag message in a single driver, so keeping this
churn out of scsi_adjust_queue_depth is a clear win.

Now that the usage of scsi_adjust_queue_depth is more obvious we can
also remove all the trivial instances in ->slave_alloc or ->slave_configure
that just set it to the cmd_per_lun default.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>

Enable VQs early like we do for restore.
This makes it possible to drop the scan callback,
moving scanning into the probe function, and making
code simpler.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

We cancel event work on device removal, but an interrupt
could trigger immediately after this, and queue it
again.

To fix, set a flag.

Loosely based on patch by Paolo Bonzini
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Michael S. Tsirkin noticed a race condition:
we reset device on freeze, but system WQ is still
running so it might try adding bufs to a VQ meanwhile.

To fix, switch to handling events from the freezable WQ.
Reported-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
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 restore returns, virtio scsi violated
this rule on restore by kicking event vq within restore.

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

We currently kick event within virtscsi_init,
before host is fully initialized.

This can in theory confuse guest if device
consumes the buffers immediately.

To fix,  move virtscsi_kick_event_all out to scan/restore.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

change_queue_depth allows changing per-target queue depth via sysfs.

It also allows the SCSI midlayer to ramp down the number of concurrent
inflight requests in response to a SCSI BUSY status response and allows
the midlayer to ramp the count back up to the device maximum when the
BUSY condition has resolved.
Signed-off-by: NVenkatesh Srinivas <venkateshs@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The spinlock of tgt_lock is only for serializing read and write
req_vq, one lockless seqcount is enough for the purpose.

On one 16core VM with vhost-scsi backend, the patch can improve
IOPS with 3% on random read test.
Signed-off-by: NMing Lei <ming.lei@canonical.com>
[Add initialization in virtscsi_target_alloc. - Paolo]
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Even though the virtio-scsi spec guarantees that all requests related
to the TMF will have been completed by the time the TMF itself completes,
the request queue's callback might not have run yet.  This causes requests
to be completed more than once, and as a result triggers a variety of
BUGs or oopses.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NVenkatesh Srinivas <venkateshs@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Calling the workqueue interface on uninitialized work items isn't a
good idea even if they're zeroed. It's not failing catastrophically only
through happy accidents.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This patch updates virtscsi_probe() to setup necessary Scsi_Host
level protection resources. (currently hardcoded to 1)

It changes virtscsi_add_cmd() to attach outgoing / incoming
protection SGLs preceeding the data payload, and is using the
new virtio_scsi_cmd_req_pi->pi_bytes[out,in] field to signal
to signal to vhost/scsi bytes to expect for protection data.

(Add missing #include <linux/blkdev.h> for blk_integrity - sfr + nab)
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@dev.mellanox.co.il>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

This triggers every time we do a SCSI abort:

virtscsi_tmf -> virtscsi_kick_cmd (grab lock and call) -> virtscsi_add_cmd
	-> virtqueue_add_sgs (GFP_NOIO)

Logs look like this:
 sd 0:0:0:0: [sda] abort
 BUG: sleeping function called from invalid context at mm/slub.c:966
 in_atomic(): 1, irqs_disabled(): 1, pid: 6, name: kworker/u2:0
 3 locks held by kworker/u2:0/6:
  #0:  ("scsi_tmf_%d"shost->host_no){......}, at: [<c0153180>] process_one_work+0xe0/0x3d0
  #1:  ((&(&cmd->abort_work)->work)){......}, at: [<c0153180>] process_one_work+0xe0/0x3d0
  #2:  (&(&virtscsi_vq->vq_lock)->rlock){......}, at: [<c043f508>] virtscsi_kick_cmd+0x18/0x1b0
 CPU: 0 PID: 6 Comm: kworker/u2:0 Not tainted 3.15.0-rc5+ #110
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-rc1-0-gb1d4dc9-20140515_140003-nilsson.home.kraxel.org 04/01/2014
 Workqueue: scsi_tmf_0 scmd_eh_abort_handler
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>

Taken almost entirely from Nicholas Bellinger's scsi-mq conversion.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NNicholas Bellinger <nab@linux-iscsi.org>

Access to tgt->req_vq is strictly serialized by spin_lock
of tgt->tgt_lock, so the ACCESS_ONCE() isn't necessary.

smp_read_barrier_depends() in virtscsi_req_done was introduced
to order reading req_vq and decreasing tgt->reqs, but it isn't
needed now because req_vq is read from
scsi->req_vqs[vq->index - VIRTIO_SCSI_VQ_BASE] instead of
tgt->req_vq, so remove the unnecessary barrier.

Also remove related comment about the barrier.
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

virtscsi_init calls virtscsi_remove_vqs on err, even before initializing
the vqs. The latter calls virtscsi_set_affinity, so let's check the
pointer there before setting affinity on it.

This fixes a panic when setting device's num_queues=2 on RHEL 6.5:

qemu-system-x86_64 ... \
-device virtio-scsi-pci,id=scsi0,addr=0x13,...,num_queues=2 \
-drive file=/stor/vm/dummy.raw,id=drive-scsi-disk,... \
-device scsi-hd,drive=drive-scsi-disk,...

[    0.354734] scsi0 : Virtio SCSI HBA
[    0.379504] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
[    0.380141] IP: [<ffffffff814741ef>] __virtscsi_set_affinity+0x4f/0x120
[    0.380141] PGD 0
[    0.380141] Oops: 0000 [#1] SMP
[    0.380141] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.0+ #5
[    0.380141] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2007
[    0.380141] task: ffff88003c9f0000 ti: ffff88003c9f8000 task.ti: ffff88003c9f8000
[    0.380141] RIP: 0010:[<ffffffff814741ef>]  [<ffffffff814741ef>] __virtscsi_set_affinity+0x4f/0x120
[    0.380141] RSP: 0000:ffff88003c9f9c08  EFLAGS: 00010256
[    0.380141] RAX: 0000000000000000 RBX: ffff88003c3a9d40 RCX: 0000000000001070
[    0.380141] RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000
[    0.380141] RBP: ffff88003c9f9c28 R08: 00000000000136c0 R09: ffff88003c801c00
[    0.380141] R10: ffffffff81475229 R11: 0000000000000008 R12: 0000000000000000
[    0.380141] R13: ffffffff81cc7ca8 R14: ffff88003cac3d40 R15: ffff88003cac37a0
[    0.380141] FS:  0000000000000000(0000) GS:ffff88003e400000(0000) knlGS:0000000000000000
[    0.380141] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[    0.380141] CR2: 0000000000000020 CR3: 0000000001c0e000 CR4: 00000000000006f0
[    0.380141] Stack:
[    0.380141]  ffff88003c3a9d40 0000000000000000 ffff88003cac3d80 ffff88003cac3d40
[    0.380141]  ffff88003c9f9c48 ffffffff814742e8 ffff88003c26d000 ffff88003c26d000
[    0.380141]  ffff88003c9f9c68 ffffffff81474321 ffff88003c26d000 ffff88003c3a9d40
[    0.380141] Call Trace:
[    0.380141]  [<ffffffff814742e8>] virtscsi_set_affinity+0x28/0x40
[    0.380141]  [<ffffffff81474321>] virtscsi_remove_vqs+0x21/0x50
[    0.380141]  [<ffffffff81475231>] virtscsi_init+0x91/0x240
[    0.380141]  [<ffffffff81365290>] ? vp_get+0x50/0x70
[    0.380141]  [<ffffffff81475544>] virtscsi_probe+0xf4/0x280
[    0.380141]  [<ffffffff81363ea5>] virtio_dev_probe+0xe5/0x140
[    0.380141]  [<ffffffff8144c669>] driver_probe_device+0x89/0x230
[    0.380141]  [<ffffffff8144c8ab>] __driver_attach+0x9b/0xa0
[    0.380141]  [<ffffffff8144c810>] ? driver_probe_device+0x230/0x230
[    0.380141]  [<ffffffff8144c810>] ? driver_probe_device+0x230/0x230
[    0.380141]  [<ffffffff8144ac1c>] bus_for_each_dev+0x8c/0xb0
[    0.380141]  [<ffffffff8144c499>] driver_attach+0x19/0x20
[    0.380141]  [<ffffffff8144bf28>] bus_add_driver+0x198/0x220
[    0.380141]  [<ffffffff8144ce9f>] driver_register+0x5f/0xf0
[    0.380141]  [<ffffffff81d27c91>] ? spi_transport_init+0x79/0x79
[    0.380141]  [<ffffffff8136403b>] register_virtio_driver+0x1b/0x30
[    0.380141]  [<ffffffff81d27d19>] init+0x88/0xd6
[    0.380141]  [<ffffffff81d27c18>] ? scsi_init_procfs+0x5b/0x5b
[    0.380141]  [<ffffffff81ce88a7>] do_one_initcall+0x7f/0x10a
[    0.380141]  [<ffffffff81ce8aa7>] kernel_init_freeable+0x14a/0x1de
[    0.380141]  [<ffffffff81ce8b3b>] ? kernel_init_freeable+0x1de/0x1de
[    0.380141]  [<ffffffff817dec20>] ? rest_init+0x80/0x80
[    0.380141]  [<ffffffff817dec29>] kernel_init+0x9/0xf0
[    0.380141]  [<ffffffff817e68fc>] ret_from_fork+0x7c/0xb0
[    0.380141]  [<ffffffff817dec20>] ? rest_init+0x80/0x80
[    0.380141] RIP  [<ffffffff814741ef>] __virtscsi_set_affinity+0x4f/0x120
[    0.380141]  RSP <ffff88003c9f9c08>
[    0.380141] CR2: 0000000000000020
[    0.380141] ---[ end trace 8074b70c3d5e1d73 ]---
[    0.475018] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
[    0.475018]
[    0.475068] Kernel Offset: 0x0 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffff9fffffff)
[    0.475068] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009

[jejb: checkpatch fixes]
Signed-off-by: NFam Zheng <famz@redhat.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

vqs are freed in virtscsi_freeze but the hotcpu_notifier is not
unregistered. We will have a use-after-free usage when the notifier
callback is called after virtscsi_freeze.

Fixes: 285e71ea
("virtio-scsi: reset virtqueue affinity when doing cpu hotplug")

Cc: stable@vger.kernel.org
Signed-off-by: NAsias He <asias.hejun@gmail.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

If virtqueue_get_buf() returned with a NULL pointer avoid a possibly
endless loop by checking for a broken virtqueue.
Signed-off-by: NHeinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This lets the transport do endian conversion if necessary, and insulates
the drivers from the difference.

Most drivers can use the simple helpers virtio_cread() and virtio_cwrite().
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

The freeze and restore functions defined in virtio drivers are used
for suspend and hibernate, so CONFIG_PM_SLEEP is more appropriate than
CONFIG_PM. This patch replace all CONFIG_PM with CONFIG_PM_SLEEP for
virtio drivers that implement freeze and restore callbacks.
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Reviewed-by: NAmit Shah <amit.shah@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

vscsi->num_queues counts the number of request virtqueue which does not
include the control and event virtqueue. It is wrong to subtract
VIRTIO_SCSI_VQ_BASE from vscsi->num_queues.

This patch fixes the following panic.

(qemu) device_del scsi0

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
 IP: [<ffffffff8179b29f>] __virtscsi_set_affinity+0x6f/0x120
 PGD 0
 Oops: 0000 [#1] SMP
 Modules linked in:
 CPU: 0 PID: 659 Comm: kworker/0:1 Not tainted 3.11.0-rc2+ #1172
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 Workqueue: kacpi_hotplug _handle_hotplug_event_func
 task: ffff88007bee1cc0 ti: ffff88007bfe4000 task.ti: ffff88007bfe4000
 RIP: 0010:[<ffffffff8179b29f>]  [<ffffffff8179b29f>] __virtscsi_set_affinity+0x6f/0x120
 RSP: 0018:ffff88007bfe5a38  EFLAGS: 00010202
 RAX: 0000000000000010 RBX: ffff880077fd0d28 RCX: 0000000000000050
 RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000000
 RBP: ffff88007bfe5a58 R08: ffff880077f6ff00 R09: 0000000000000001
 R10: ffffffff8143e673 R11: 0000000000000001 R12: 0000000000000001
 R13: ffff880077fd0800 R14: 0000000000000000 R15: ffff88007bf489b0
 FS:  0000000000000000(0000) GS:ffff88007ea00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: 0000000000000020 CR3: 0000000079f8b000 CR4: 00000000000006f0
 Stack:
  ffff880077fd0d28 0000000000000000 ffff880077fd0800 0000000000000008
  ffff88007bfe5a78 ffffffff8179b37d ffff88007bccc800 ffff88007bccc800
  ffff88007bfe5a98 ffffffff8179b3b6 ffff88007bccc800 ffff880077fd0d28
 Call Trace:
  [<ffffffff8179b37d>] virtscsi_set_affinity+0x2d/0x40
  [<ffffffff8179b3b6>] virtscsi_remove_vqs+0x26/0x50
  [<ffffffff8179c7d2>] virtscsi_remove+0x82/0xa0
  [<ffffffff814cb6b2>] virtio_dev_remove+0x22/0x70
  [<ffffffff8167ca49>] __device_release_driver+0x69/0xd0
  [<ffffffff8167cb9d>] device_release_driver+0x2d/0x40
  [<ffffffff8167bb96>] bus_remove_device+0x116/0x150
  [<ffffffff81679936>] device_del+0x126/0x1e0
  [<ffffffff81679a06>] device_unregister+0x16/0x30
  [<ffffffff814cb889>] unregister_virtio_device+0x19/0x30
  [<ffffffff814cdad6>] virtio_pci_remove+0x36/0x80
  [<ffffffff81464ae7>] pci_device_remove+0x37/0x70
  [<ffffffff8167ca49>] __device_release_driver+0x69/0xd0
  [<ffffffff8167cb9d>] device_release_driver+0x2d/0x40
  [<ffffffff8167bb96>] bus_remove_device+0x116/0x150
  [<ffffffff81679936>] device_del+0x126/0x1e0
  [<ffffffff8145edfc>] pci_stop_bus_device+0x9c/0xb0
  [<ffffffff8145f036>] pci_stop_and_remove_bus_device+0x16/0x30
  [<ffffffff81474a9e>] acpiphp_disable_slot+0x8e/0x150
  [<ffffffff81474f6a>] hotplug_event_func+0xba/0x1a0
  [<ffffffff814906c8>] ? acpi_os_release_object+0xe/0x12
  [<ffffffff81475911>] _handle_hotplug_event_func+0x31/0x70
  [<ffffffff810b5333>] process_one_work+0x183/0x500
  [<ffffffff810b66e2>] worker_thread+0x122/0x400
  [<ffffffff810b65c0>] ? manage_workers+0x2d0/0x2d0
  [<ffffffff810bc5de>] kthread+0xce/0xe0
  [<ffffffff810bc510>] ? kthread_freezable_should_stop+0x70/0x70
  [<ffffffff81ca045c>] ret_from_fork+0x7c/0xb0
  [<ffffffff810bc510>] ? kthread_freezable_should_stop+0x70/0x70
 Code: 01 00 00 00 74 59 45 31 e4 83 bb c8 01 00 00 02 74 46 66 2e 0f 1f 84 00 00 00 00 00 49 63 c4 48 c1 e0 04 48 8b bc 0
3 10 02 00 00 <48> 8b 47 20 48 8b 80 d0 01 00 00 48 8b 40 50 48 85 c0 74 07 be
 RIP  [<ffffffff8179b29f>] __virtscsi_set_affinity+0x6f/0x120
  RSP <ffff88007bfe5a38>
 CR2: 0000000000000020
 ---[ end trace 99679331a3775f48 ]---

CC: stable@vger.kernel.org
Signed-off-by: NAsias He <asias@redhat.com>
Reviewed-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Add hot cpu notifier to reset the request virtqueue affinity
when doing cpu hotplug.

Cc: linux-scsi@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: NAsias He <asias@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This patch adds queue steering to virtio-scsi.  When a target is sent
multiple requests, we always drive them to the same queue so that FIFO
processing order is kept.  However, if a target was idle, we can choose
a queue arbitrarily.  In this case the queue is chosen according to the
current VCPU, so the driver expects the number of request queues to be
equal to the number of VCPUs.  This makes it easy and fast to select
the queue, and also lets the driver optimize the IRQ affinity for the
virtqueues (each virtqueue's affinity is set to the CPU that "owns"
the queue).

The speedup comes from improving cache locality and giving CPU affinity
to the virtqueues, which is why this scheme was selected.  Assuming that
the thread that is sending requests to the device is I/O-bound, it is
likely to be sleeping at the time the ISR is executed, and thus executing
the ISR on the same processor that sent the requests is cheap.

However, the kernel will not execute the ISR on the "best" processor
unless you explicitly set the affinity.  This is because in practice
you will have many such I/O-bound processes and thus many otherwise
idle processors.  Then the kernel will execute the ISR on a random
processor, rather than the one that is sending requests to the device.

The alternative to per-CPU virtqueues is per-target virtqueues.  To
achieve the same locality, we could dynamically choose the virtqueue's
affinity based on the CPU of the last task that sent a request.  This
is less appealing because we do not set the affinity directly---we only
provide a hint to the irqbalanced running in userspace.  Dynamically
changing the affinity only works if the userspace applies the hint
fast enough.

Cc: linux-scsi@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: NAsias He <asias@redhat.com>
Tested-by: NVenkatesh Srinivas <venkateshs@google.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Avoid duplicated code in all of the callers.

Cc: linux-scsi@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: NAsias He <asias@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This will be needed soon in order to retrieve the per-target
struct.

Cc: linux-scsi@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: NAsias He <asias@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

virtio_scsi_target_state is now empty.  We will find new uses for it in
the next few patches, so this patch does not drop it completely.

And as James suggested, we use entries target_alloc and target_destroy
in the host template to allocate and destroy the virtio_scsi_target_state
of each target, attach this struct to scsi_target->hostdata. Now
we can get at it from the sdev with scsi_target(sdev)->hostdata.
No messing around with fixed size arrays and bulk memory allocation
and no need to pass in the maximum target size as a parameter because
everything should now happen dynamically.

Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: NAsias He <asias@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

It's a bit clearer, and add_buf is going away.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Reviewed-by: NAsias He <asias@redhat.com>

Using the new virtqueue_add_sgs function lets us simplify the queueing
path.  In particular, all data protected by the tgt_lock is just gone
(multiqueue will find a new use for the lock).
Signed-off-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NAsias He <asias@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Convert the virtio-scsi driver to use pr_err() instead of printk().
Signed-off-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

CONFIG_HOTPLUG is going away as an option.  As a result, the __dev*
markings need to be removed.

This change removes the use of __devinit, __devexit_p, __devinitdata,
__devinitconst, and __devexit from these drivers.

Based on patches originally written by Bill Pemberton, but redone by me
in order to handle some of the coding style issues better, by hand.

Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Adam Radford <linuxraid@lsi.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We simplified virtqueue_add_buf(), make it clear in the callers.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

virtscsi_queuecommand was leaking memory when the virtio queue was full.

Tested: Guest operates correctly even with very small queue sizes, validated
we're not leaking kmalloc-192 sized allocations anymore.
Signed-off-by: NEric Northup <digitaleric@google.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Support the LUN parameter change event.  Currently, the host fires this event
when the capacity of a disk is changed from the virtual machine monitor.
The resize then appears in the kernel log like this:

  sd 0:0:0:0: [sda] 46137344 512-byte logical blocks: (23.6 GB/22.0 GIb)
  sda: detected capacity change from 22548578304 to 23622320128
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

virtio-scsi needs to report LUNs greater than 256 using the "flat"
format.  Because the Linux SCSI layer just maps the SCSI LUN to
an u32, without any parsing, these end up in the range from 16640
to 32767.  Fix max_lun to account for the possibility that logical
unit numbers are encoded with the "flat" format.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

The sg struct is used without being initialized, which breaks
when CONFIG_DEBUG_SG is enabled.

Cc: stable@vger.kernel.org
Signed-off-by: NRichard W.M. Jones <rjones@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

When using the commands below to write some data to a virtio-scsi LUN of the
QEMU guest(32-bit) with 1G physical memory(qemu -m 1024), the qemu will crash.

        # sudo mkfs.ext4 /dev/sdb  (/dev/sdb is the virtio-scsi LUN.)
        # sudo mount /dev/sdb /mnt
        # dd if=/dev/zero of=/mnt/file bs=1M count=1024

In current implementation, sg_set_buf is called to add buffers to sg list which
is put into the virtqueue eventually. But if there are some HighMem pages in
table->sgl you can not get virtual address by sg_virt. So, sg_virt(sg_elem) may
return NULL value. This will cause QEMU exit when virtqueue_map_sg is called
in QEMU because an invalid GPA is passed by virtqueue.

Two solutions are discussed here:
http://lkml.indiana.edu/hypermail/linux/kernel/1207.3/00675.html

Finally, value assignment approach was adopted because:

Value assignment creates a well-formed scatterlist, because the termination
marker in source sg_list has been set in blk_rq_map_sg(). The last entry of the
source sg_list is just copied to the the last entry in destination list.  Note
that, for now, virtio_ring does not care about the form of the scatterlist and
simply processes the first out_num + in_num consecutive elements of the sg[]
array.

I have tested the patch on my workstation. QEMU would not crash any more.

Cc: <stable@vger.kernel.org> # 3.4: 4fe74b1c: [SCSI] virtio-scsi: SCSI driver
Signed-off-by: NWang Sen <senwang@linux.vnet.ibm.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

This patch changes virtio-scsi to use a new virtio_driver->scan() callback
so that scsi_scan_host() can be properly invoked once virtio_dev_probe() has
set add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK) to signal active virtio-ring
operation, instead of from within virtscsi_probe().

This fixes a bug where SCSI LUN scanning for both virtio-scsi-raw and
virtio-scsi/tcm_vhost setups was happening before VIRTIO_CONFIG_S_DRIVER_OK
had been set, causing VIRTIO_SCSI_S_BAD_TARGET to occur.  This fixes a bug
with virtio-scsi/tcm_vhost where LUN scan was not detecting LUNs.

Tested with virtio-scsi-raw + virtio-scsi/tcm_vhost w/ IBLOCK on 3.5-rc2 code.
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

This patch implements the hotplug support for virtio-scsi.
When there is a device attached/detached, the virtio-scsi driver will be
signaled via event virtual queue and it will add/remove the scsi device
in question automatically.
Signed-off-by: NSen Wang <senwang@linux.vnet.ibm.com>
Signed-off-by: NCong Meng <mc@linux.vnet.ibm.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

To improve performance for I/O to different targets, add a separate
scatterlist for each of them.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

We do not need the sglist after calling virtqueue_add_buf.  Hence we
can "pipeline" the locked operations and start preparing the sglist
for the next request while we kick the virtqueue.

Together with the previous two patches, this improves performance as
follows.  For a simple "if=/dev/sda of=/dev/null bs=128M iflag=direct"
(the source being a 10G disk, residing entirely in the host buffer cache),
the additional locking does not cause any penalty with only one dd
process, but 2 simultaneous I/O operations improve their times by 3%:

               number of simultaneous dd
                   1               2
 ----------------------------------------
 current        5.9958s        10.2640s
 patched        5.9531s         9.8663s

(Times are best of 10).
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Keep a separate lock for each virtqueue.  While not particularly
important now, it prepares the code for when we will add support
for multiple request queues.  It is also more tidy as soon as
we introduce a separate lock for the sglist.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>