scsi: target: tcmu: Userspace must not complete queued commands
When tcmu queues a new command - no matter whether in command ring or in qfull_queue - a cmd_id from IDR udev->commands is assigned to the command. If userspace sends a wrong command completion containing the cmd_id of a command on the qfull_queue, tcmu_handle_completions() finds the command in the IDR and calls tcmu_handle_completion() for it. This might do some nasty things because commands in qfull_queue do not have a valid dbi list. To fix this bug, we no longer add queued commands to the idr. Instead the cmd_id is assign when a command is written to the command ring. Due to this change I had to adapt the source code at several places where up to now an idr_for_each had been done. [mkp: fix checkpatch warnings] Link: https://lore.kernel.org/r/20200518164833.12775-1-bstroesser@ts.fujitsu.com Acked-by: Mike Christie <mchristi@redhat.com> Signed-off-by: Bodo Stroesser <bstroesser@ts.fujitsu.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Bodo Stroesser
Martin K. Petersen
parent
5482d56bfe
commit
61fb248221
@ -882,41 +882,24 @@ static inline size_t tcmu_cmd_get_cmd_size(struct tcmu_cmd *tcmu_cmd,
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return command_size;
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}
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static int tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd, unsigned int tmo,
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struct timer_list *timer)
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static void tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd, unsigned int tmo,
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struct timer_list *timer)
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{
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struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
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int cmd_id;
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if (tcmu_cmd->cmd_id)
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goto setup_timer;
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cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 1, USHRT_MAX, GFP_NOWAIT);
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if (cmd_id < 0) {
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pr_err("tcmu: Could not allocate cmd id.\n");
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return cmd_id;
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}
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tcmu_cmd->cmd_id = cmd_id;
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pr_debug("allocated cmd %u for dev %s tmo %lu\n", tcmu_cmd->cmd_id,
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udev->name, tmo / MSEC_PER_SEC);
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setup_timer:
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if (!tmo)
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return 0;
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return;
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tcmu_cmd->deadline = round_jiffies_up(jiffies + msecs_to_jiffies(tmo));
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if (!timer_pending(timer))
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mod_timer(timer, tcmu_cmd->deadline);
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return 0;
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pr_debug("Timeout set up for cmd %p, dev = %s, tmo = %lu\n", tcmu_cmd,
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tcmu_cmd->tcmu_dev->name, tmo / MSEC_PER_SEC);
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}
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static int add_to_qfull_queue(struct tcmu_cmd *tcmu_cmd)
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{
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struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
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unsigned int tmo;
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int ret;
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/*
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* For backwards compat if qfull_time_out is not set use
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@ -931,13 +914,11 @@ static int add_to_qfull_queue(struct tcmu_cmd *tcmu_cmd)
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else
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tmo = TCMU_TIME_OUT;
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ret = tcmu_setup_cmd_timer(tcmu_cmd, tmo, &udev->qfull_timer);
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if (ret)
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return ret;
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tcmu_setup_cmd_timer(tcmu_cmd, tmo, &udev->qfull_timer);
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list_add_tail(&tcmu_cmd->queue_entry, &udev->qfull_queue);
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pr_debug("adding cmd %u on dev %s to ring space wait queue\n",
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tcmu_cmd->cmd_id, udev->name);
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pr_debug("adding cmd %p on dev %s to ring space wait queue\n",
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tcmu_cmd, udev->name);
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return 0;
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}
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@ -959,7 +940,7 @@ static int queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, sense_reason_t *scsi_err)
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struct tcmu_mailbox *mb;
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struct tcmu_cmd_entry *entry;
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struct iovec *iov;
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int iov_cnt, ret;
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int iov_cnt, cmd_id;
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uint32_t cmd_head;
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uint64_t cdb_off;
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bool copy_to_data_area;
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@ -1060,14 +1041,21 @@ static int queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, sense_reason_t *scsi_err)
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}
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entry->req.iov_bidi_cnt = iov_cnt;
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ret = tcmu_setup_cmd_timer(tcmu_cmd, udev->cmd_time_out,
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&udev->cmd_timer);
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if (ret) {
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tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cnt);
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cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 1, USHRT_MAX, GFP_NOWAIT);
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if (cmd_id < 0) {
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pr_err("tcmu: Could not allocate cmd id.\n");
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tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cnt);
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*scsi_err = TCM_OUT_OF_RESOURCES;
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return -1;
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}
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tcmu_cmd->cmd_id = cmd_id;
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pr_debug("allocated cmd id %u for cmd %p dev %s\n", tcmu_cmd->cmd_id,
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tcmu_cmd, udev->name);
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tcmu_setup_cmd_timer(tcmu_cmd, udev->cmd_time_out, &udev->cmd_timer);
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entry->hdr.cmd_id = tcmu_cmd->cmd_id;
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/*
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@ -1279,50 +1267,39 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
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return handled;
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}
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static int tcmu_check_expired_cmd(int id, void *p, void *data)
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static void tcmu_check_expired_ring_cmd(struct tcmu_cmd *cmd)
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{
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struct tcmu_cmd *cmd = p;
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struct tcmu_dev *udev = cmd->tcmu_dev;
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u8 scsi_status;
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struct se_cmd *se_cmd;
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bool is_running;
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if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
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return 0;
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if (!time_after(jiffies, cmd->deadline))
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return 0;
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return;
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is_running = test_bit(TCMU_CMD_BIT_INFLIGHT, &cmd->flags);
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set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
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list_del_init(&cmd->queue_entry);
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se_cmd = cmd->se_cmd;
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cmd->se_cmd = NULL;
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if (is_running) {
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/*
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* If cmd_time_out is disabled but qfull is set deadline
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* will only reflect the qfull timeout. Ignore it.
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*/
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if (!udev->cmd_time_out)
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return 0;
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pr_debug("Timing out inflight cmd %u on dev %s.\n",
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cmd->cmd_id, cmd->tcmu_dev->name);
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set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
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/*
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* target_complete_cmd will translate this to LUN COMM FAILURE
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*/
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scsi_status = SAM_STAT_CHECK_CONDITION;
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list_del_init(&cmd->queue_entry);
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cmd->se_cmd = NULL;
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} else {
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list_del_init(&cmd->queue_entry);
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idr_remove(&udev->commands, id);
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tcmu_free_cmd(cmd);
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scsi_status = SAM_STAT_TASK_SET_FULL;
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}
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target_complete_cmd(se_cmd, SAM_STAT_CHECK_CONDITION);
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}
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pr_debug("Timing out cmd %u on dev %s that is %s.\n",
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id, udev->name, is_running ? "inflight" : "queued");
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static void tcmu_check_expired_queue_cmd(struct tcmu_cmd *cmd)
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{
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struct se_cmd *se_cmd;
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target_complete_cmd(se_cmd, scsi_status);
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return 0;
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if (!time_after(jiffies, cmd->deadline))
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return;
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list_del_init(&cmd->queue_entry);
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se_cmd = cmd->se_cmd;
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tcmu_free_cmd(cmd);
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pr_debug("Timing out queued cmd %p on dev %s.\n",
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cmd, cmd->tcmu_dev->name);
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target_complete_cmd(se_cmd, SAM_STAT_TASK_SET_FULL);
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}
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static void tcmu_device_timedout(struct tcmu_dev *udev)
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@ -1407,16 +1384,15 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
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return &udev->se_dev;
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}
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static bool run_qfull_queue(struct tcmu_dev *udev, bool fail)
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static void run_qfull_queue(struct tcmu_dev *udev, bool fail)
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{
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struct tcmu_cmd *tcmu_cmd, *tmp_cmd;
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LIST_HEAD(cmds);
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bool drained = true;
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sense_reason_t scsi_ret;
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int ret;
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if (list_empty(&udev->qfull_queue))
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return true;
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return;
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pr_debug("running %s's cmdr queue forcefail %d\n", udev->name, fail);
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@ -1425,11 +1401,10 @@ static bool run_qfull_queue(struct tcmu_dev *udev, bool fail)
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list_for_each_entry_safe(tcmu_cmd, tmp_cmd, &cmds, queue_entry) {
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list_del_init(&tcmu_cmd->queue_entry);
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pr_debug("removing cmd %u on dev %s from queue\n",
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tcmu_cmd->cmd_id, udev->name);
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pr_debug("removing cmd %p on dev %s from queue\n",
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tcmu_cmd, udev->name);
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if (fail) {
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idr_remove(&udev->commands, tcmu_cmd->cmd_id);
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/*
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* We were not able to even start the command, so
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* fail with busy to allow a retry in case runner
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@ -1444,10 +1419,8 @@ static bool run_qfull_queue(struct tcmu_dev *udev, bool fail)
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ret = queue_cmd_ring(tcmu_cmd, &scsi_ret);
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if (ret < 0) {
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pr_debug("cmd %u on dev %s failed with %u\n",
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tcmu_cmd->cmd_id, udev->name, scsi_ret);
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idr_remove(&udev->commands, tcmu_cmd->cmd_id);
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pr_debug("cmd %p on dev %s failed with %u\n",
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tcmu_cmd, udev->name, scsi_ret);
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/*
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* Ignore scsi_ret for now. target_complete_cmd
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* drops it.
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@ -1462,13 +1435,11 @@ static bool run_qfull_queue(struct tcmu_dev *udev, bool fail)
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* the queue
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*/
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list_splice_tail(&cmds, &udev->qfull_queue);
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drained = false;
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break;
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}
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}
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tcmu_set_next_deadline(&udev->qfull_queue, &udev->qfull_timer);
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return drained;
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}
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static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
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@ -1652,6 +1623,8 @@ static void tcmu_dev_kref_release(struct kref *kref)
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if (tcmu_check_and_free_pending_cmd(cmd) != 0)
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all_expired = false;
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}
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if (!list_empty(&udev->qfull_queue))
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all_expired = false;
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idr_destroy(&udev->commands);
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WARN_ON(!all_expired);
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@ -2037,9 +2010,6 @@ static void tcmu_reset_ring(struct tcmu_dev *udev, u8 err_level)
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mutex_lock(&udev->cmdr_lock);
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idr_for_each_entry(&udev->commands, cmd, i) {
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if (!test_bit(TCMU_CMD_BIT_INFLIGHT, &cmd->flags))
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continue;
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pr_debug("removing cmd %u on dev %s from ring (is expired %d)\n",
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cmd->cmd_id, udev->name,
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test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags));
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@ -2076,6 +2046,8 @@ static void tcmu_reset_ring(struct tcmu_dev *udev, u8 err_level)
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del_timer(&udev->cmd_timer);
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run_qfull_queue(udev, false);
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mutex_unlock(&udev->cmdr_lock);
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}
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@ -2699,6 +2671,7 @@ static void find_free_blocks(void)
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static void check_timedout_devices(void)
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{
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struct tcmu_dev *udev, *tmp_dev;
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struct tcmu_cmd *cmd, *tmp_cmd;
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LIST_HEAD(devs);
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spin_lock_bh(&timed_out_udevs_lock);
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@ -2709,9 +2682,24 @@ static void check_timedout_devices(void)
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spin_unlock_bh(&timed_out_udevs_lock);
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mutex_lock(&udev->cmdr_lock);
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idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
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tcmu_set_next_deadline(&udev->inflight_queue, &udev->cmd_timer);
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/*
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* If cmd_time_out is disabled but qfull is set deadline
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* will only reflect the qfull timeout. Ignore it.
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*/
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if (udev->cmd_time_out) {
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list_for_each_entry_safe(cmd, tmp_cmd,
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&udev->inflight_queue,
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queue_entry) {
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tcmu_check_expired_ring_cmd(cmd);
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}
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tcmu_set_next_deadline(&udev->inflight_queue,
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&udev->cmd_timer);
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}
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list_for_each_entry_safe(cmd, tmp_cmd, &udev->qfull_queue,
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queue_entry) {
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tcmu_check_expired_queue_cmd(cmd);
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}
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tcmu_set_next_deadline(&udev->qfull_queue, &udev->qfull_timer);
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mutex_unlock(&udev->cmdr_lock);
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