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path: root/drivers/scsi/virtio_scsi.c
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* virtio-scsi: reset virtqueue affinity when doing cpu hotplugWanlong Gao2013-04-081-0/+29
| | | | | | | | | | | Add hot cpu notifier to reset the request virtqueue affinity when doing cpu hotplug. Cc: linux-scsi@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Reviewed-by: Asias He <asias@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio-scsi: introduce multiqueue supportPaolo Bonzini2013-04-081-28/+254
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Reviewed-by: Asias He <asias@redhat.com> Tested-by: Venkatesh Srinivas <venkateshs@google.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio-scsi: push vq lock/unlock into virtscsi_vq_donePaolo Bonzini2013-04-081-13/+9
| | | | | | | | | | Avoid duplicated code in all of the callers. Cc: linux-scsi@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Reviewed-by: Asias He <asias@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio-scsi: pass struct virtio_scsi to virtqueue completion functionPaolo Bonzini2013-04-081-8/+9
| | | | | | | | | | | This will be needed soon in order to retrieve the per-target struct. Cc: linux-scsi@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Reviewed-by: Asias He <asias@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio-scsi: redo allocation of target dataWanlong Gao2013-04-081-46/+25
| | | | | | | | | | | | | | | | | | | | 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: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Reviewed-by: Asias He <asias@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio_scsi: use virtqueue_add_inbuf() for virtscsi_kick_event.Rusty Russell2013-03-201-2/+2
| | | | | | | It's a bit clearer, and add_buf is going away. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Reviewed-by: Asias He <asias@redhat.com>
* virtio-scsi: use virtqueue_add_sgs for command buffersWanlong Gao2013-03-201-63/+37
| | | | | | | | | | | 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: Wanlong Gao <gaowanlong@cn.fujitsu.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Asias He <asias@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* virtio-scsi: use pr_err() instead of printk()Wanlong Gao2013-03-121-4/+4
| | | | | | | | Convert the virtio-scsi driver to use pr_err() instead of printk(). Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Drivers: scsi: remove __dev* attributes.Greg Kroah-Hartman2013-01-031-3/+3
| | | | | | | | | | | | | | | | 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds2012-12-201-11/+13
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull virtio update from Rusty Russell: "Some nice cleanups, and even a patch my wife did as a "live" demo for Latinoware 2012. There's a slightly non-trivial merge in virtio-net, as we cleaned up the virtio add_buf interface while DaveM accepted the mq virtio-net patches." * tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (27 commits) virtio_console: Add support for remoteproc serial virtio_console: Merge struct buffer_token into struct port_buffer virtio: add drv_to_virtio to make code clearly virtio: use dev_to_virtio wrapper in virtio virtio-mmio: Fix irq parsing in command line parameter virtio_console: Free buffers from out-queue upon close virtio: Convert dev_printk(KERN_<LEVEL> to dev_<level>( virtio_console: Use kmalloc instead of kzalloc virtio_console: Free buffer if splice fails virtio: tools: make it clear that virtqueue_add_buf() no longer returns > 0 virtio: scsi: make it clear that virtqueue_add_buf() no longer returns > 0 virtio: rpmsg: make it clear that virtqueue_add_buf() no longer returns > 0 virtio: net: make it clear that virtqueue_add_buf() no longer returns > 0 virtio: console: make it clear that virtqueue_add_buf() no longer returns > 0 virtio: make virtqueue_add_buf() returning 0 on success, not capacity. virtio: console: don't rely on virtqueue_add_buf() returning capacity. virtio_net: don't rely on virtqueue_add_buf() returning capacity. virtio-net: remove unused skb_vnet_hdr->num_sg field virtio-net: correct capacity math on ring full virtio: move queue_index and num_free fields into core struct virtqueue. ...
| * virtio: scsi: make it clear that virtqueue_add_buf() no longer returns > 0Rusty Russell2012-12-181-11/+13
| | | | | | | | | | | | We simplified virtqueue_add_buf(), make it clear in the callers. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* | [SCSI] virtio_scsi: fix memory leak on full queue condition.Eric Northup2012-11-271-0/+2
|/ | | | | | | | | | | 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: Eric Northup <digitaleric@google.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] virtio-scsi: support online resizing of disksPaolo Bonzini2012-10-091-1/+30
| | | | | | | | | | | | 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: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] virtio-scsi: fix LUNs greater than 255Paolo Bonzini2012-10-091-1/+5
| | | | | | | | | | | 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: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] virtio-scsi: initialize scatterlist structureRichard W.M. Jones2012-10-091-1/+1
| | | | | | | | | | The sg struct is used without being initialized, which breaks when CONFIG_DEBUG_SG is enabled. Cc: stable@vger.kernel.org Signed-off-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] scsi: virtio-scsi: Fix address translation failure of HighMem pages ↵Wang Sen2012-09-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | used by sg list 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: 4fe74b1: [SCSI] virtio-scsi: SCSI driver Signed-off-by: Wang Sen <senwang@linux.vnet.ibm.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] virtio-scsi: Add vdrv->scan for post VIRTIO_CONFIG_S_DRIVER_OK LUN ↵Nicholas Bellinger2012-07-201-3/+12
| | | | | | | | | | | | | | | | | | | | scanning 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: Nicholas Bellinger <nab@linux-iscsi.org> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] virtio-scsi: hotplug support for virtio-scsiCong Meng2012-07-201-1/+123
| | | | | | | | | | | | 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: Sen Wang <senwang@linux.vnet.ibm.com> Signed-off-by: Cong Meng <mc@linux.vnet.ibm.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] virtio-scsi: split scatterlist per targetPaolo Bonzini2012-07-201-47/+94
| | | | | | | | To improve performance for I/O to different targets, add a separate scatterlist for each of them. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] virtio-scsi: release sg_lock after add_bufPaolo Bonzini2012-07-201-2/+2
| | | | | | | | | | | | | | | | | | | | | | | 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: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] virtio-scsi: split locking per vqPaolo Bonzini2012-07-201-25/+52
| | | | | | | | | | 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: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] virtio-scsi: unlock during kickPaolo Bonzini2012-07-201-1/+3
| | | | | | | | Separate virtqueue_kick_prepare from virtqueue_notify, so that the expensive vmexit is done without holding the lock. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] virtio_scsi: fix TMF use-after-freePaolo Bonzini2012-05-101-11/+13
| | | | | | | | | | | | | | Fix a use-after-free in the TMF path, where cmd may have been already freed by virtscsi_complete_free when wait_for_completion restarts executing virtscsi_tmf. Technically a race, but in practice the command will always be freed long before the completion waiter is awoken. The fix is to make callers specifying a completion responsible for freeing the command in all cases. Signed-off-by: Hu Tao <hutao@cn.fujitsu.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] virtio-scsi: SCSI driver for QEMU based virtual machinesPaolo Bonzini2012-02-191-0/+594
The virtio-scsi HBA is the basis of an alternative storage stack for QEMU-based virtual machines (including KVM). Compared to virtio-blk it is more scalable, because it supports many LUNs on a single PCI slot), more powerful (it more easily supports passthrough of host devices to the guest) and more easily extensible (new SCSI features implemented by QEMU should not require updating the driver in the guest). Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
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