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- 10 Aug, 2023 2 commits
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Mike Christie authored
Rename vhost_scsi_iov_to_sgl to vhost_scsi_map_iov_to_sgl so it matches matches the naming style used for vhost_scsi_copy_iov_to_sgl. Signed-off-by:
Mike Christie <michael.christie@oracle.com> Message-Id: <20230709202859.138387-3-michael.christie@oracle.com> Signed-off-by:
Michael S. Tsirkin <mst@redhat.com> Acked-by:
Stefan Hajnoczi <stefanha@redhat.com>
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Mike Christie authored
The linux block layer requires bios/requests to have lengths with a 512 byte alignment. Some drivers/layers like dm-crypt and the directi IO code will test for it and just fail. Other drivers like SCSI just assume the requirement is met and will end up in infinte retry loops. The problem for drivers like SCSI is that it uses functions like blk_rq_cur_sectors and blk_rq_sectors which divide the request's length by 512. If there's lefovers then it just gets dropped. But other code in the block/scsi layer may use blk_rq_bytes/blk_rq_cur_bytes and end up thinking there is still data left and try to retry the cmd. We can then end up getting stuck in retry loops where part of the block/scsi thinks there is data left, but other parts think we want to do IOs of zero length. Linux will always check for alignment, but windows will not. When vhost-scsi then translates the iovec it gets from a windows guest to a scatterlist, we can end up with sg items where the sg->length is not divisible by 512 due to the misaligned offset: sg[0].offset = 255; sg[0].length = 3841; sg... sg[N].offset = 0; sg[N].length = 255; When the lio backends then convert the SG to bios or other iovecs, we end up sending them with the same misaligned values and can hit the issues above. This just has us drop down to allocating a temp page and copying the data when we detect a misaligned buffer and the IO is large enough that it will get split into multiple bad IOs. Signed-off-by:
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- 03 Jul, 2023 4 commits
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Mike Christie authored
This has vhost-scsi support the worker ioctls by calling the vhost_worker_ioctl helper. With a single worker, the single thread becomes a bottlneck when trying to use 3 or more virtqueues like: fio --filename=/dev/sdb --direct=1 --rw=randrw --bs=4k \ --ioengine=libaio --iodepth=128 --numjobs=3 With the patches and doing a worker per vq, we can scale to at least 16 vCPUs/vqs (that's my system limit) with the same command fio command above with numjobs=16: fio --filename=/dev/sdb --direct=1 --rw=randrw --bs=4k \ --ioengine=libaio --iodepth=64 --numjobs=16 which gives around 2002K IOPs. Note that for testing I dropped depth to 64 above because the vhost/virt layer supports only 1024 total commands per device. And the only tuning I did was set LIO's emulate_pr to 0 to avoid LIO's PR lock in the main IO path which becomes an issue at around 12 jobs/virtqueues. Signed-off-by:
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Mike Christie authored
With one worker we will always send the scsi cmd responses then send the TMF rsp, because LIO will always complete the scsi cmds first then call into us to send the TMF response. With multiple workers, the IO vq workers could be running while the TMF/ctl vq worker is running so this has us do a flush before completing the TMF to make sure cmds are completed when it's work is later queued and run. Signed-off-by:
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Mike Christie authored
Convert from vhost_work_queue to vhost_vq_work_queue so we can remove vhost_work_queue. Signed-off-by:
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Mike Christie authored
This patch separates the scsi cmd completion code paths so we can complete cmds based on their vq instead of having all cmds complete on the same worker/CPU. This will be useful with the next patches that allow us to create mulitple worker threads and bind them to different vqs, and we can have completions running on different threads/CPUs. Signed-off-by:
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- 21 Apr, 2023 5 commits
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Mike Christie authored
We on longer need to hold the vhost_scsi_mutex the entire time we set/clear the endpoint. The tv_tpg_mutex handles tpg accesses not related to the tpg list, the port link/unlink functions use the tv_tpg_mutex while accessing the tpg->vhost_scsi pointer, vhost_scsi_do_plug will no longer queue events after the virtqueue's backend has been cleared and flushed, and we don't drop our refcount to the tpg until after we have stopped cmds and wait for outstanding cmds to complete. This moves the vhost_scsi_mutex use to it's documented use of being used to access the tpg list. We then don't need to hold it while a flush is being performed causing other device's vhost_scsi_set_endpoint and vhost_scsi_make_tpg/vhost_scsi_drop_tpg calls to have to wait on a flakey device. Signed-off-by:
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Mike Christie authored
We are using the vhost_scsi_mutex to make sure vhost_scsi_port_link and vhost_scsi_port_unlink see if vhost_scsi_clear_endpoint has cleared tpg->vhost_scsi and it can't be freed while they are using. However, we currently set the tpg->vhost_scsi pointer while holding tv_tpg_mutex. So, we can just hold that while calling vhost_scsi_hotplug/hotunplug. We then don't need to hold the vhost_scsi_mutex while vhost_scsi_clear_endpoint is holding it and doing a flush which could cause the LUN map/unmap to have to wait on another device's flush. Signed-off-by:
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Mike Christie authored
We currenly hold the vhost_scsi_mutex while clearing the endpoint and while performing vhost_scsi_do_plug, so tpg->vhost_scsi can't be freed from uder us, and to make sure anything queued is handled by the full call in vhost_scsi_clear_endpoint. This patch removes the need for the vhost_scsi_mutex for the latter case. In the next patches, we won't hold the vhost_scsi_mutex while flushing so this patch adds a check for the clearing of the virtqueue from vhost_scsi_clear_endpoint. We then know that once vhost_scsi_clear_endpoint has cleared the backend that no new events will be queued, and the flush after the vhost_vq_set_backend(vq, NULL) call will see everything that's been queued to that point. So the flush will then handle all events without the need for the vhost_scsi_mutex. Signed-off-by:
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Mike Christie authored
We don't need the device mutex in vhost_scsi_do_plug because: 1. we have the vhost_scsi_mutex so the tpg->vhost_scsi pointer will not change on us and the vhost_scsi can't be freed from under us if it was set. 2. vhost_scsi_clear_endpoint will stop the virtqueues and flush them while holding the vhost_scsi_mutex so we know once vhost_scsi_clear_endpoint has completed that vhost_scsi_do_plug can't send new events and any queued ones have completed. So this patch drops the device mutex use in vhost_scsi_do_plug. Signed-off-by:
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Mike Christie authored
We currently hold the vhost_scsi_mutex the entire time we are running vhost_scsi_clear_endpoint. One of the reasons for this is that it prevents userspace from being able to free the se_tpg from under us after we have called target_undepend_item. However, it forces management operations for for other devices to have to wait on a flakey device's: vhost_scsi_clear_endpoint -> vhost_scsi_flush() call which can which can take a long time. This moves the target_undepend_item call and the tpg unsetup code to after we have stopped new IO from starting up and after we have waited on running IO. We can then release our refcount on the tpg and session knowing our device is no longer accessing them. We can then drop the vhost_scsi_mutex use during thee flush call in later patches in this set, when we have removed other reasons for holding it. Signed-off-by:
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- 04 Apr, 2023 2 commits
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Mike Christie authored
We normally clear the endpoint then unmap LUNs so the devices are fully shutdown when the LUN is unmapped, but it's legal to unmap before clearing. If the user does that while TMFs are running then we can end up crashing. vhost_scsi_port_unlink assumes that the LUN's tmf struct will always be on the tmf_queue list. However, if a TMF is running then it will have been removed while it's executing. If we do a LUN unmap at this time, then we assume the entry is on the list and just start accessing it and free it. This fixes the bug by just allocating the vhost_scsi_tmf struct when it's needed like is done with the se_tmr struct that's needed when we submit the TMF. In this path perf is not an issue and we can use GFP_KERNEL since it won't swing directly back on us, so we don't need to preallocate the struct. Signed-off-by:
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Mike Christie authored
If vhost_scsi_setup_vq_cmds fails we leave the tpg->vhost_scsi pointer set. If the device is freed and then the user unmaps the LUN, the call to vhost_scsi_port_unlink -> vhost_scsi_hotunplug will see the that tpg->vhost_scsi is still set and try to use it. This has us clear the vhost_scsi pointer in the failure path. It also has us take tv_tpg_mutex in this failure path, because tv_tpg_vhost_count is accessed under this mutex in vhost_scsi_drop_nexus and in the future we will want to serialize access to tpg->vhost_scsi with that mutex instead of the vhost_scsi_mutex. Signed-off-by:
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- 30 Mar, 2023 1 commit
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Jens Axboe authored
This returns a pointer to the current iovec entry in the iterator. Only useful with ITER_IOVEC right now, but it prepares us to treat ITER_UBUF and ITER_IOVEC identically for the first segment. Rename struct iov_iter->iov to iov_iter->__iov to find any potentially troublesome spots, and also to prevent anyone from adding new code that accesses iter->iov directly. Signed-off-by:Jens Axboe <axboe@kernel.dk>
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- 17 Mar, 2023 1 commit
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Dmitry Bogdanov authored
Remove callouts that are identical to the default implementations in TCM Core. Signed-off-by:
Dmitry Bogdanov <d.bogdanov@yadro.com> Link: https://lore.kernel.org/r/20230313181110.20566-9-d.bogdanov@yadro.comSigned-off-by:
Martin K. Petersen <martin.petersen@oracle.com>
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- 21 Feb, 2023 1 commit
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Bo Liu authored
Follow the advice of the Documentation/filesystems/sysfs.rst and show() should only use sysfs_emit() or sysfs_emit_at() when formatting the value to be returned to user space. Signed-off-by:
Bo Liu <liubo03@inspur.com> Message-Id: <20230129091145.2837-1-liubo03@inspur.com> Signed-off-by:
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- 27 Jan, 2023 1 commit
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Jason Wang authored
Al Viro said: """ Since "vhost/scsi: fix reuse of &vq->iov[out] in response" we have this: cmd->tvc_resp_iov = vq->iov[vc.out]; cmd->tvc_in_iovs = vc.in; combined with iov_iter_init(&iov_iter, ITER_DEST, &cmd->tvc_resp_iov, cmd->tvc_in_iovs, sizeof(v_rsp)); in vhost_scsi_complete_cmd_work(). We used to have ->tvc_resp_iov _pointing_ to vq->iov[vc.out]; back then iov_iter_init() asked to set an iovec-backed iov_iter over the tail of vq->iov[], with length being the amount of iovecs in the tail. Now we have a copy of one element of that array. Fortunately, the members following it in the containing structure are two non-NULL kernel pointers, so copy_to_iter() will not copy anything beyond the first iovec - kernel pointer is not (on the majority of architectures) going to be accepted by access_ok() in copyout() and it won't be skipped since the "length" (in reality - another non-NULL kernel pointer) won't be zero. So it's not going to give a guest-to-qemu escalation, but it's definitely a bug. Frankly, my preference would be to verify that the very first iovec is long enough to hold rsp_size. Due to the above, any users that try to give us vq->iov[vc.out].iov_len < sizeof(struct virtio_scsi_cmd_resp) would currently get a failure in vhost_scsi_complete_cmd_work() anyway. """ However, the spec doesn't say anything about the legacy descriptor layout for the respone. So this patch tries to not assume the response to reside in a single separate descriptor which is what commit 79c14141 ("vhost/scsi: Convert completion path to use") tries to achieve towards to ANY_LAYOUT. This is done by allocating and using dedicate resp iov in the command. To be safety, start with UIO_MAXIOV to be consistent with the limitation that we advertise to the vhost_get_vq_desc(). Testing with the hacked virtio-scsi driver that use 1 descriptor for 1 byte in the response. Reported-by:Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin Coddington <bcodding@redhat.com> Cc: Nicholas Bellinger <nab@linux-iscsi.org> Fixes: a77ec83a ("vhost/scsi: fix reuse of &vq->iov[out] in response") Signed-off-by:
Jason Wang <jasowang@redhat.com> Message-Id: <20230119073647.76467-1-jasowang@redhat.com> Signed-off-by:
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- 25 Nov, 2022 1 commit
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Al Viro authored
READ/WRITE proved to be actively confusing - the meanings are "data destination, as used with read(2)" and "data source, as used with write(2)", but people keep interpreting those as "we read data from it" and "we write data to it", i.e. exactly the wrong way. Call them ITER_DEST and ITER_SOURCE - at least that is harder to misinterpret... Signed-off-by:
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- 11 Aug, 2022 2 commits
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Mike Christie authored
We are currently hard coded to always create 128 IO virtqueues, so this adds a modparam to control it. For large systems where we are ok with using memory for virtqueues it allows us to add up to 1024. This limit was just selected becuase that's qemu's limit. Signed-off-by:
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Mike Christie authored
Qemu takes it's num_queues limit then adds the fixed queues (control and event) to the total it will request from the kernel. So when a user requests 128 (or qemu does it's num_queues calculation based on vCPUS and other system limits), we hit errors due to userspace trying to setup 130 queues when vhost-scsi has a hard coded limit of 128. This has vhost-scsi adjust it's max so we can do a total of 130 virtqueues (128 IO and 2 fixed). For the case where the user has 128 vCPUs the guest OS can then nicely map each IO virtqueue to a vCPU and not have the odd case where 2 vCPUs share a virtqueue. Signed-off-by:
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- 09 Aug, 2022 1 commit
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Al Viro authored
Most of the users immediately follow successful iov_iter_get_pages() with advancing by the amount it had returned. Provide inline wrappers doing that, convert trivial open-coded uses of those. BTW, iov_iter_get_pages() never returns more than it had been asked to; such checks in cifs ought to be removed someday... Reviewed-by:
Jeff Layton <jlayton@kernel.org> Signed-off-by:
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- 31 May, 2022 2 commits
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Mike Christie authored
This patch renames vhost_work_dev_flush to just vhost_dev_flush to relfect that it flushes everything on the device and that drivers don't know/care that polls are based on vhost_works. Drivers just flush the entire device and polls, and works for vhost-scsi management TMFs and IO net virtqueues, etc all are flushed. Signed-off-by:
Stefano Garzarella <sgarzare@redhat.com> Message-Id: <20220517180850.198915-9-michael.christie@oracle.com> Signed-off-by:
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Mike Christie authored
The flush after vhost_dev_cleanup is not needed because: 1. It doesn't do anything. vhost_dev_cleanup will stop the worker thread so the flush call will just return since the worker has not device. 2. It's not needed for the re-queue case. vhost_scsi_evt_handle_kick grabs the mutex and if the backend is NULL will return without queueing a work. vhost_scsi_clear_endpoint will set the backend to NULL under the vq->mutex then drops the mutex and does a flush. So we know when vhost_scsi_clear_endpoint has dropped the mutex after clearing the backend no evt related work will be able to requeue. The flush would then make sure any queued evts are run and return. Signed-off-by:
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- 05 Sep, 2021 1 commit
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Cai Huoqing authored
use SPDX-License-Identifier instead of a verbose license text Signed-off-by:
Cai Huoqing <caihuoqing@baidu.com> Link: https://lore.kernel.org/r/20210821123320.734-1-caihuoqing@baidu.comSigned-off-by:
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- 03 Jul, 2021 3 commits
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Mike Christie authored
vhost_scsi_flush will flush everything, so we can clear the backends then flush, then destroy. We don't need to flush before each vq destruction because after the flush we will have made sure there can be no new cmds started and there are no running cmds. Signed-off-by:
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Mike Christie authored
The vhost work flush function was flushing the entire work queue, so there is no need for the double vhost_work_dev_flush calls in vhost_scsi_flush. And we do not need to call vhost_poll_flush for each poller because that call also ends up flushing the same work queue thread the vhost_work_dev_flush call flushed. Signed-off-by:
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Mike Christie authored
vhost_work_flush doesn't do anything with the work arg. This patch drops it and then renames vhost_work_flush to vhost_work_dev_flush to reflect that the function flushes all the works in the dev and not just a specific queue or work item. Signed-off-by:
Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Link: https://lore.kernel.org/r/20210525174733.6212-2-michael.christie@oracle.comReviewed-by:
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- 04 Mar, 2021 5 commits
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Mike Christie authored
Convert vhost-scsi to use the LIO wq cmd submission helper. Link: https://lore.kernel.org/r/20210227170006.5077-18-michael.christie@oracle.comSigned-off-by:
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Mike Christie authored
tcm_loop could be used like a normal block device, so we can't use GFP_KERNEL and should use GFP_NOIO. This adds a gfp_t arg to target_cmd_init_cdb() and converts the users. For every driver but loop GFP_KERNEL is kept. This will also be useful in subsequent patches where loop needs to do target_submit_prep() from interrupt context to get a ref to the se_device, and so it will need to use GFP_ATOMIC. Link: https://lore.kernel.org/r/20210227170006.5077-16-michael.christie@oracle.comTested-by:
Laurence Oberman <loberman@redhat.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
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Mike Christie authored
target_submit_cmd_map_sgls() is being removed, so convert vhost-scsi to the new submission API. This has it use target_init_cmd(), target_submit_prep(), target_submit() because we need to have LIO core map sgls which is now done in target_submit_prep(), and in the next patches we will do the target_submit step from the LIO workqueue. Note: vhost-scsi never calls target_stop_session() so target_submit_cmd_map_sgls() never failed (in the new API target_init_cmd() handles target_stop_session() being called when cmds are being submitted). If it were to have used target_stop_session() and got an error, we would have hit a refcount bug like xen and usb, because it does: if (rc < 0) { transport_send_check_condition_and_sense(se_cmd, TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0); transport_generic_free_cmd(se_cmd, 0); } transport_send_check_condition_and_sense() calls queue_status which does transport_generic_free_cmd(), and then we do an extra transport_generic_free_cmd() call above which would have dropped the refcount to -1 and the refcount code would spit out errors. Link: https://lore.kernel.org/r/20210227170006.5077-12-michael.christie@oracle.com Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: -
Ming Lei authored
Allocation hint should have belonged to sbitmap. Also, when sbitmap's depth is high and there is no need to use mulitple wakeup queues, user can benefit from percpu allocation hint too. Move allocation hint into sbitmap, then SCSI device queue can benefit from allocation hint when converting to plain sbitmap. Convert vhost/scsi.c to use sbitmap allocation with percpu alloc hint. This is more efficient than the previous approach. Link: https://lore.kernel.org/r/20210122023317.687987-5-ming.lei@redhat.com Cc: Omar Sandoval <osandov@fb.com> Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Sumanesh Samanta <sumanesh.samanta@broadcom.com> Cc: Ewan D. Milne <emilne@redhat.com> Cc: Mike Christie <michael.christie@oracle.com> Cc: virtualization@lists.linux-foundation.org Tested-by:
Sumanesh Samanta <sumanesh.samanta@broadcom.com> Reviewed-by:
Hannes Reinecke <hare@suse.de> Signed-off-by:
Ming Lei <ming.lei@redhat.com> Signed-off-by:
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Ming Lei authored
Currently the allocation round_robin info is maintained by sbitmap_queue. However, bit allocation really belongs to sbitmap. Move it there. Link: https://lore.kernel.org/r/20210122023317.687987-3-ming.lei@redhat.com Cc: Omar Sandoval <osandov@fb.com> Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Sumanesh Samanta <sumanesh.samanta@broadcom.com> Cc: Ewan D. Milne <emilne@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: virtualization@lists.linux-foundation.org Tested-by:
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- 23 Feb, 2021 1 commit
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Dongli Zhang authored
The size of 'struct vhost_scsi' is order-10 (~2.3MB). It may take long time delay by kzalloc() to compact memory pages by retrying multiple times when there is a lack of high-order pages. As a result, there is latency to create a VM (with vhost-scsi) or to hotadd vhost-scsi-based storage. The prior commit 595cb754 ("vhost/scsi: use vmalloc for order-10 allocation") prefers to fallback only when really needed, while this patch allocates with kvzalloc() with __GFP_NORETRY implicitly set to avoid retrying memory pages compact for multiple times. The __GFP_NORETRY is implicitly set if the size to allocate is more than PAGE_SZIE and when __GFP_RETRY_MAYFAIL is not explicitly set. Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Joe Jin <joe.jin@oracle.com> Signed-off-by:
Dongli Zhang <dongli.zhang@oracle.com> Link: https://lore.kernel.org/r/20210123080853.4214-1-dongli.zhang@oracle.comSigned-off-by:
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- 18 Dec, 2020 1 commit
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Zhang Changzhong authored
Fix to return a negative error code from the error handling case instead of 0, as done elsewhere in this function. Fixes: 25b98b64 ("vhost scsi: alloc cmds per vq instead of session") Reported-by:
Hulk Robot <hulkci@huawei.com> Signed-off-by:
Zhang Changzhong <zhangchangzhong@huawei.com> Link: https://lore.kernel.org/r/1607071411-33484-1-git-send-email-zhangchangzhong@huawei.comSigned-off-by:
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- 25 Nov, 2020 1 commit
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Mike Christie authored
vhost scsi owns the scsi se_cmd but lio frees the se_cmd->se_tmr before calling release_cmd, so while with normal cmd completion we can access the se_cmd from the vhost work, we can't do the same with se_cmd->se_tmr. This has us copy the tmf response in vhost_scsi_queue_tm_rsp to our internal vhost-scsi tmf struct for when it gets sent to the guest from our worker thread. Fixes: efd838fe ("vhost scsi: Add support for LUN resets.") Signed-off-by:
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- 15 Nov, 2020 4 commits
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Mike Christie authored
In newer versions of virtio-scsi we just reset the timer when an a command times out, so TMFs are never sent for the cmd time out case. However, in older kernels and for the TMF inject cases, we can still get resets and we end up just failing immediately so the guest might see the device get offlined and IO errors. For the older kernel cases, we want the same end result as the modern virtio-scsi driver where we let the lower levels fire their error handling and handle the problem. And at the upper levels we want to wait. This patch ties the LUN reset handling into the LIO TMF code which will just wait for outstanding commands to complete like we are doing in the modern virtio-scsi case. Note: I did not handle the ABORT case to keep this simple. For ABORTs LIO just waits on the cmd like how it does for the RESET case. If an ABORT fails, the guest OS ends up escalating to LUN RESET, so in the end we get the same behavior where we wait on the outstanding cmds. Signed-off-by:
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Mike Christie authored
Move code to parse lun from req's lun_buf to helper, so tmf code can use it in the next patch. Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com> Acked-by:
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Mike Christie authored
We might not do the final se_cmd put from vhost_scsi_complete_cmd_work. When the last put happens a little later then we could race where vhost_scsi_complete_cmd_work does vhost_signal, the guest runs and sends more IO, and vhost_scsi_handle_vq runs but does not find any free cmds. This patch has us delay completing the cmd until the last lio core ref is dropped. We then know that once we signal to the guest that the cmd is completed that if it queues a new command it will find a free cmd. Signed-off-by:
Maurizio Lombardi <mlombard@redhat.com> Link: https://lore.kernel.org/r/1604986403-4931-4-git-send-email-michael.christie@oracle.comSigned-off-by:
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Mike Christie authored
We currently are limited to 256 cmds per session. This leads to problems where if the user has increased virtqueue_size to more than 2 or cmd_per_lun to more than 256 vhost_scsi_get_tag can fail and the guest will get IO errors. This patch moves the cmd allocation to per vq so we can easily match whatever the user has specified for num_queues and virtqueue_size/cmd_per_lun. It also makes it easier to control how much memory we preallocate. For cases, where perf is not as important and we can use the current defaults (1 vq and 128 cmds per vq) memory use from preallocate cmds is cut in half. For cases, where we are willing to use more memory for higher perf, cmd mem use will now increase as the num queues and queue depth increases. Signed-off-by:
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- 29 Jul, 2020 1 commit
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Michael S. Tsirkin authored
vhost/scsi doesn't handle type conversion correctly for request type when using virtio 1.0 and up for BE, or cross-endian platforms. Fix it up using vhost_32_to_cpu. Cc: stable@vger.kernel.org Signed-off-by:
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