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vhost-scsi: change removed flag into small state machine

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Introduce EMPTY, PRESENT and REMOVED states for Vhost SCSI targets. This
does not introduce any functional changes but opens a way to stop using
both removed flag and spdk_scsi_dev pointer as indicator if device is
removed or not.

Change-Id: Iecd76ffe9e8121cc1359b1e268eb21679d13598e
Signed-off-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/447070
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
This commit is contained in:
Pawel Wodkowski 2019-03-04 16:20:21 +01:00 committed by Jim Harris
parent b9b1c9592e
commit b1a6197068
1 changed files with 32 additions and 13 deletions
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45
lib/vhost/vhost_scsi.c
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@ -67,9 +67,23 @@
#define VIRTIO_SCSI_EVENTQ 1
#define VIRTIO_SCSI_REQUESTQ 2
enum spdk_scsi_dev_vhost_status {
/* Target ID is empty. */
VHOST_SCSI_DEV_EMPTY,
/* Target ID occupied. */
VHOST_SCSI_DEV_PRESENT,
/* Target ID is occupied but removal is in progress. */
VHOST_SCSI_DEV_REMOVING,
/* In session - device (SCSI target) seen but removed. */
VHOST_SCSI_DEV_REMOVED,
};
struct spdk_scsi_dev_vhost_state {
struct spdk_scsi_dev *dev;
bool removed;
enum spdk_scsi_dev_vhost_status status;
spdk_vhost_event_fn remove_cb;
void *remove_ctx;
};
@ -167,6 +181,8 @@ remove_scsi_tgt(struct spdk_vhost_scsi_dev *svdev,
dev = state->dev;
state->dev = NULL;
assert(state->status == VHOST_SCSI_DEV_REMOVING);
state->status = VHOST_SCSI_DEV_EMPTY;
spdk_scsi_dev_destruct(dev);
if (state->remove_cb) {
state->remove_cb(&svdev->vdev, state->remove_ctx);
@ -219,10 +235,11 @@ process_removed_devs(struct spdk_vhost_scsi_session *svsession)
state = &svsession->scsi_dev_state[i];
dev = state->dev;
if (dev && state->removed && !spdk_scsi_dev_has_pending_tasks(dev)) {
if (dev && state->status == VHOST_SCSI_DEV_REMOVING && !spdk_scsi_dev_has_pending_tasks(dev)) {
/* detach the device from this session */
spdk_scsi_dev_free_io_channels(dev);
state->dev = NULL;
state->status = VHOST_SCSI_DEV_REMOVED;
/* try to detach it globally */
spdk_vhost_lock();
spdk_vhost_dev_foreach_session(&svsession->svdev->vdev,
@ -374,11 +391,11 @@ spdk_vhost_scsi_task_init_target(struct spdk_vhost_scsi_task *task, const __u8 *
state = &svsession->scsi_dev_state[lun[1]];
task->scsi_dev = state->dev;
if (state->dev == NULL || svsession->scsi_dev_state[lun[1]].removed) {
if (state->dev == NULL || state->status != VHOST_SCSI_DEV_PRESENT) {
/* If dev has been hotdetached, return 0 to allow sending
* additional hotremove event via sense codes.
*/
return svsession->scsi_dev_state[lun[1]].removed ? 0 : -1;
return state->status != VHOST_SCSI_DEV_EMPTY ? 0 : -1;
}
task->scsi.target_port = spdk_scsi_dev_find_port_by_id(task->scsi_dev, 0);
@ -923,10 +940,10 @@ spdk_vhost_scsi_session_add_tgt(struct spdk_vhost_dev *vdev,
/* unset the SCSI target so that all I/O to it will be rejected */
svsession->scsi_dev_state[scsi_tgt_num].dev = NULL;
/* unset the removed flag so that we won't reply with SCSI hotremove
/* Set status to EMPTY so that we won't reply with SCSI hotremove
* sense codes - the device hasn't ever been added.
*/
svsession->scsi_dev_state[scsi_tgt_num].removed = false;
svsession->scsi_dev_state[scsi_tgt_num].status = VHOST_SCSI_DEV_EMPTY;
/* Return with no error. We'll continue allocating io_channels for
* other sessions on this device in hopes they succeed. The sessions
@ -1000,12 +1017,13 @@ spdk_vhost_scsi_dev_add_tgt(struct spdk_vhost_dev *vdev, int scsi_tgt_num,
lun_id_list[0] = 0;
bdev_names_list[0] = (char *)bdev_name;
state->removed = false;
state->status = VHOST_SCSI_DEV_PRESENT;
state->dev = spdk_scsi_dev_construct(target_name, bdev_names_list, lun_id_list, 1,
SPDK_SPC_PROTOCOL_IDENTIFIER_SAS,
spdk_vhost_scsi_lun_hotremove, svdev);
if (state->dev == NULL) {
state->status = VHOST_SCSI_DEV_EMPTY;
SPDK_ERRLOG("Couldn't create spdk SCSI target '%s' using bdev '%s' in controller: %s\n",
target_name, bdev_name, vdev->name);
return -EINVAL;
@ -1043,8 +1061,8 @@ spdk_vhost_scsi_session_remove_tgt(struct spdk_vhost_dev *vdev,
/* Mark the target for removal */
svsession = (struct spdk_vhost_scsi_session *)vsession;
state = &svsession->scsi_dev_state[scsi_tgt_num];
assert(!state->removed);
state->removed = true;
assert(state->status == VHOST_SCSI_DEV_PRESENT);
state->status = VHOST_SCSI_DEV_REMOVING;
/* If the session isn't currently polled, unset the dev straight away */
if (vsession->lcore == -1) {
@ -1087,7 +1105,8 @@ spdk_vhost_scsi_dev_remove_tgt(struct spdk_vhost_dev *vdev, unsigned scsi_tgt_nu
return -ENODEV;
}
if (scsi_dev_state->removed) {
assert(scsi_dev_state->status != VHOST_SCSI_DEV_EMPTY);
if (scsi_dev_state->status != VHOST_SCSI_DEV_PRESENT) {
SPDK_WARNLOG("%s: 'Target %u' has been already marked to hotremove.\n",
vdev->name, scsi_tgt_num);
return -EBUSY;
@ -1095,7 +1114,7 @@ spdk_vhost_scsi_dev_remove_tgt(struct spdk_vhost_dev *vdev, unsigned scsi_tgt_nu
scsi_dev_state->remove_cb = cb_fn;
scsi_dev_state->remove_ctx = cb_arg;
scsi_dev_state->removed = true;
scsi_dev_state->status = VHOST_SCSI_DEV_REMOVING;
spdk_vhost_dev_foreach_session(vdev, spdk_vhost_scsi_session_remove_tgt,
(void *)(uintptr_t)scsi_tgt_num);
@ -1273,10 +1292,10 @@ spdk_vhost_scsi_start_cb(struct spdk_vhost_dev *vdev,
SPDK_ERRLOG("%s: failed to alloc io_channel for SCSI target %"PRIu32"\n", vdev->name, i);
/* unset the SCSI target so that all I/O to it will be rejected */
svsession->scsi_dev_state[i].dev = NULL;
/* unset the removed flag so that we won't reply with SCSI hotremove
/* set EMPTY state so that we won't reply with SCSI hotremove
* sense codes - the device hasn't ever been added.
*/
svsession->scsi_dev_state[i].removed = false;
svsession->scsi_dev_state[i].status = VHOST_SCSI_DEV_EMPTY;
continue;
}
}