linux.git/drivers/vhost/scsi.c, branch v5.13

scsi: target: vhost-scsi: Use LIO wq cmd submission helper

2021-03-04T22:37:02+00:00

Convert vhost-scsi to use the LIO wq cmd submission helper.

Link: https://lore.kernel.org/r/20210227170006.5077-18-michael.christie@oracle.com
Signed-off-by: Mike Christie 
Reviewed-by: Stefan Hajnoczi 
Signed-off-by: Martin K. Petersen

scsi: target: core: Add gfp_t arg to target_cmd_init_cdb()

2021-03-04T22:37:02+00:00

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.com
Tested-by: Laurence Oberman 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: target: vhost-scsi: Convert to new submission API

2021-03-04T22:37:01+00:00

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" 
Cc: Stefan Hajnoczi 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Stefan Hajnoczi 
Signed-off-by: Mike Christie 
Signed-off-by: Martin K. Petersen

scsi: sbitmap: Move allocation hint into sbitmap

2021-03-04T22:36:59+00:00

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 
Cc: Kashyap Desai 
Cc: Sumanesh Samanta 
Cc: Ewan D. Milne 
Cc: Mike Christie 
Cc: virtualization@lists.linux-foundation.org
Tested-by: Sumanesh Samanta 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Ming Lei 
Signed-off-by: Martin K. Petersen

scsi: sbitmap: Maintain allocation round_robin in sbitmap

2021-03-04T22:36:59+00:00

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 
Cc: Kashyap Desai 
Cc: Sumanesh Samanta 
Cc: Ewan D. Milne 
Cc: Hannes Reinecke 
Cc: virtualization@lists.linux-foundation.org
Tested-by: Sumanesh Samanta 
Reviewed-by: Hannes Reinecke 
Signed-off-by: Ming Lei 
Signed-off-by: Martin K. Petersen

vhost scsi: alloc vhost_scsi with kvzalloc() to avoid delay

2021-02-23T12:52:56+00:00

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 595cb754983d ("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 
Cc: Joe Jin 
Signed-off-by: Dongli Zhang 
Link: https://lore.kernel.org/r/20210123080853.4214-1-dongli.zhang@oracle.com
Signed-off-by: Michael S. Tsirkin 
Acked-by: Jason Wang

vhost scsi: fix error return code in vhost_scsi_set_endpoint()

2020-12-18T21:14:31+00:00

Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: 25b98b64e284 ("vhost scsi: alloc cmds per vq instead of session")
Reported-by: Hulk Robot 
Signed-off-by: Zhang Changzhong 
Link: https://lore.kernel.org/r/1607071411-33484-1-git-send-email-zhangchangzhong@huawei.com
Signed-off-by: Michael S. Tsirkin

vhost scsi: fix lun reset completion handling

2020-11-25T09:22:13+00:00

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: efd838fec17b ("vhost scsi: Add support for LUN resets.")
Signed-off-by: Mike Christie 
Acked-by: Stefan Hajnoczi 
Link: https://lore.kernel.org/r/1605887459-3864-1-git-send-email-michael.christie@oracle.com
Signed-off-by: Michael S. Tsirkin

vhost scsi: Add support for LUN resets.

2020-11-15T22:30:55+00:00

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: Mike Christie 
Link: https://lore.kernel.org/r/1604986403-4931-6-git-send-email-michael.christie@oracle.com
Signed-off-by: Michael S. Tsirkin 
Acked-by: Stefan Hajnoczi

vhost scsi: add lun parser helper

2020-11-15T22:30:55+00:00

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: Mike Christie 
Reviewed-by: Paolo Bonzini 
Acked-by: Jason Wang 
Link: https://lore.kernel.org/r/1604986403-4931-5-git-send-email-michael.christie@oracle.com
Signed-off-by: Michael S. Tsirkin 
Acked-by: Stefan Hajnoczi