linux.git/drivers/vhost/scsi.c, branch v5.15

vhost scsi: Convert to SPDX identifier

2021-09-05T20:23:08+00:00

use SPDX-License-Identifier instead of a verbose license text

Signed-off-by: Cai Huoqing 
Link: https://lore.kernel.org/r/20210821123320.734-1-caihuoqing@baidu.com
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Stefan Hajnoczi

vhost-scsi: reduce flushes during endpoint clearing

2021-07-03T08:50:54+00:00

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: Mike Christie 
Link: https://lore.kernel.org/r/20210525174733.6212-4-michael.christie@oracle.com
Signed-off-by: Michael S. Tsirkin

vhost-scsi: remove extra flushes

2021-07-03T08:50:54+00:00

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: Mike Christie 
Reviewed-by: Stefan Hajnoczi 
Acked-by: Jason Wang 
Link: https://lore.kernel.org/r/20210525174733.6212-3-michael.christie@oracle.com
Signed-off-by: Michael S. Tsirkin

vhost: remove work arg from vhost_work_flush

2021-07-03T08:50:54+00:00

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: Mike Christie 
Acked-by: Jason Wang 
Reviewed-by: Chaitanya Kulkarni 
Link: https://lore.kernel.org/r/20210525174733.6212-2-michael.christie@oracle.com
Reviewed-by: Stefano Garzarella 
Signed-off-by: Michael S. Tsirkin

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