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-rw-r--r--drivers/target/target_core_user.c264
1 files changed, 169 insertions, 95 deletions
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 2679e4dcd0f1..52fc1d440d23 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -83,7 +83,10 @@
/* The total size of the ring is 8M + 256K * PAGE_SIZE */
#define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
-/* Default maximum of the global data blocks(512K * PAGE_SIZE) */
+/*
+ * Default number of global data blocks(512K * PAGE_SIZE)
+ * when the unmap thread will be started.
+ */
#define TCMU_GLOBAL_MAX_BLOCKS (512 * 1024)
static u8 tcmu_kern_cmd_reply_supported;
@@ -106,6 +109,7 @@ struct tcmu_nl_cmd {
struct tcmu_dev {
struct list_head node;
struct kref kref;
+
struct se_device se_dev;
char *name;
@@ -128,10 +132,9 @@ struct tcmu_dev {
size_t data_off;
size_t data_size;
- wait_queue_head_t wait_cmdr;
struct mutex cmdr_lock;
+ struct list_head cmdr_queue;
- bool waiting_global;
uint32_t dbi_max;
uint32_t dbi_thresh;
DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
@@ -160,6 +163,7 @@ struct tcmu_dev {
struct tcmu_cmd {
struct se_cmd *se_cmd;
struct tcmu_dev *tcmu_dev;
+ struct list_head cmdr_queue_entry;
uint16_t cmd_id;
@@ -174,7 +178,16 @@ struct tcmu_cmd {
#define TCMU_CMD_BIT_EXPIRED 0
unsigned long flags;
};
-
+/*
+ * To avoid dead lock the mutex lock order should always be:
+ *
+ * mutex_lock(&root_udev_mutex);
+ * ...
+ * mutex_lock(&tcmu_dev->cmdr_lock);
+ * mutex_unlock(&tcmu_dev->cmdr_lock);
+ * ...
+ * mutex_unlock(&root_udev_mutex);
+ */
static DEFINE_MUTEX(root_udev_mutex);
static LIST_HEAD(root_udev);
@@ -182,7 +195,7 @@ static DEFINE_SPINLOCK(timed_out_udevs_lock);
static LIST_HEAD(timed_out_udevs);
static atomic_t global_db_count = ATOMIC_INIT(0);
-static struct work_struct tcmu_unmap_work;
+static struct delayed_work tcmu_unmap_work;
static struct kmem_cache *tcmu_cmd_cache;
@@ -346,10 +359,8 @@ static inline bool tcmu_get_empty_block(struct tcmu_dev *udev,
page = radix_tree_lookup(&udev->data_blocks, dbi);
if (!page) {
if (atomic_add_return(1, &global_db_count) >
- TCMU_GLOBAL_MAX_BLOCKS) {
- atomic_dec(&global_db_count);
- return false;
- }
+ TCMU_GLOBAL_MAX_BLOCKS)
+ schedule_delayed_work(&tcmu_unmap_work, 0);
/* try to get new page from the mm */
page = alloc_page(GFP_KERNEL);
@@ -380,18 +391,11 @@ static bool tcmu_get_empty_blocks(struct tcmu_dev *udev,
{
int i;
- udev->waiting_global = false;
-
for (i = tcmu_cmd->dbi_cur; i < tcmu_cmd->dbi_cnt; i++) {
if (!tcmu_get_empty_block(udev, tcmu_cmd))
- goto err;
+ return false;
}
return true;
-
-err:
- udev->waiting_global = true;
- schedule_work(&tcmu_unmap_work);
- return false;
}
static inline struct page *
@@ -437,6 +441,7 @@ static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
if (!tcmu_cmd)
return NULL;
+ INIT_LIST_HEAD(&tcmu_cmd->cmdr_queue_entry);
tcmu_cmd->se_cmd = se_cmd;
tcmu_cmd->tcmu_dev = udev;
@@ -742,6 +747,10 @@ static int tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd)
unsigned long tmo = udev->cmd_time_out;
int cmd_id;
+ /*
+ * If it was on the cmdr queue waiting we do not reset the timer
+ * for requeues and when it is finally sent to userspace.
+ */
if (tcmu_cmd->cmd_id)
return 0;
@@ -753,13 +762,31 @@ static int tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd)
tcmu_cmd->cmd_id = cmd_id;
if (!tmo)
- return 0;
+ tmo = TCMU_TIME_OUT;
+
+ pr_debug("allocated cmd %u for dev %s tmo %lu\n", tcmu_cmd->cmd_id,
+ udev->name, tmo / MSEC_PER_SEC);
tcmu_cmd->deadline = round_jiffies_up(jiffies + msecs_to_jiffies(tmo));
mod_timer(&udev->timeout, tcmu_cmd->deadline);
return 0;
}
+static int add_to_cmdr_queue(struct tcmu_cmd *tcmu_cmd)
+{
+ struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
+ int ret;
+
+ ret = tcmu_setup_cmd_timer(tcmu_cmd);
+ if (ret)
+ return ret;
+
+ list_add_tail(&tcmu_cmd->cmdr_queue_entry, &udev->cmdr_queue);
+ pr_debug("adding cmd %u on dev %s to ring space wait queue\n",
+ tcmu_cmd->cmd_id, udev->name);
+ return 0;
+}
+
/**
* queue_cmd_ring - queue cmd to ring or internally
* @tcmu_cmd: cmd to queue
@@ -768,6 +795,7 @@ static int tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd)
* Returns:
* -1 we cannot queue internally or to the ring.
* 0 success
+ * 1 internally queued to wait for ring memory to free.
*/
static sense_reason_t queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, int *scsi_err)
{
@@ -805,7 +833,8 @@ static sense_reason_t queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, int *scsi_err)
base_command_size = tcmu_cmd_get_base_cmd_size(tcmu_cmd->dbi_cnt);
command_size = tcmu_cmd_get_cmd_size(tcmu_cmd, base_command_size);
- mutex_lock(&udev->cmdr_lock);
+ if (!list_empty(&udev->cmdr_queue))
+ goto queue;
mb = udev->mb_addr;
cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
@@ -814,42 +843,18 @@ static sense_reason_t queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, int *scsi_err)
pr_warn("TCMU: Request of size %zu/%zu is too big for %u/%zu "
"cmd ring/data area\n", command_size, data_length,
udev->cmdr_size, udev->data_size);
- mutex_unlock(&udev->cmdr_lock);
*scsi_err = TCM_INVALID_CDB_FIELD;
return -1;
}
- while (!is_ring_space_avail(udev, tcmu_cmd, command_size, data_length)) {
- int ret;
- DEFINE_WAIT(__wait);
-
+ if (!is_ring_space_avail(udev, tcmu_cmd, command_size, data_length)) {
/*
* Don't leave commands partially setup because the unmap
* thread might need the blocks to make forward progress.
*/
tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cur);
tcmu_cmd_reset_dbi_cur(tcmu_cmd);
-
- prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE);
-
- pr_debug("sleeping for ring space\n");
- mutex_unlock(&udev->cmdr_lock);
- if (udev->cmd_time_out)
- ret = schedule_timeout(
- msecs_to_jiffies(udev->cmd_time_out));
- else
- ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT));
- finish_wait(&udev->wait_cmdr, &__wait);
- if (!ret) {
- pr_warn("tcmu: command timed out\n");
- *scsi_err = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
- return -1;
- }
-
- mutex_lock(&udev->cmdr_lock);
-
- /* We dropped cmdr_lock, cmd_head is stale */
- cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
+ goto queue;
}
/* Insert a PAD if end-of-ring space is too small */
@@ -924,31 +929,39 @@ static sense_reason_t queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, int *scsi_err)
UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
tcmu_flush_dcache_range(mb, sizeof(*mb));
- mutex_unlock(&udev->cmdr_lock);
/* TODO: only if FLUSH and FUA? */
uio_event_notify(&udev->uio_info);
- if (udev->cmd_time_out)
- mod_timer(&udev->timeout, round_jiffies_up(jiffies +
- msecs_to_jiffies(udev->cmd_time_out)));
-
return 0;
+
+queue:
+ if (add_to_cmdr_queue(tcmu_cmd)) {
+ *scsi_err = TCM_OUT_OF_RESOURCES;
+ return -1;
+ }
+
+ return 1;
}
static sense_reason_t
tcmu_queue_cmd(struct se_cmd *se_cmd)
{
+ struct se_device *se_dev = se_cmd->se_dev;
+ struct tcmu_dev *udev = TCMU_DEV(se_dev);
struct tcmu_cmd *tcmu_cmd;
sense_reason_t scsi_ret;
+ int ret;
tcmu_cmd = tcmu_alloc_cmd(se_cmd);
if (!tcmu_cmd)
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
- if (queue_cmd_ring(tcmu_cmd, &scsi_ret) < 0)
+ mutex_lock(&udev->cmdr_lock);
+ ret = queue_cmd_ring(tcmu_cmd, &scsi_ret);
+ mutex_unlock(&udev->cmdr_lock);
+ if (ret < 0)
tcmu_free_cmd(tcmu_cmd);
-
return scsi_ret;
}
@@ -1036,10 +1049,15 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
handled++;
}
- if (mb->cmd_tail == mb->cmd_head)
- del_timer(&udev->timeout); /* no more pending cmds */
-
- wake_up(&udev->wait_cmdr);
+ if (mb->cmd_tail == mb->cmd_head && list_empty(&udev->cmdr_queue)) {
+ del_timer(&udev->timeout);
+ /*
+ * not more pending or waiting commands so try to reclaim
+ * blocks if needed.
+ */
+ if (atomic_read(&global_db_count) > TCMU_GLOBAL_MAX_BLOCKS)
+ schedule_delayed_work(&tcmu_unmap_work, 0);
+ }
return handled;
}
@@ -1047,6 +1065,10 @@ static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
static int tcmu_check_expired_cmd(int id, void *p, void *data)
{
struct tcmu_cmd *cmd = p;
+ struct tcmu_dev *udev = cmd->tcmu_dev;
+ u8 scsi_status;
+ struct se_cmd *se_cmd;
+ bool is_running;
if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
return 0;
@@ -1054,10 +1076,27 @@ static int tcmu_check_expired_cmd(int id, void *p, void *data)
if (!time_after(jiffies, cmd->deadline))
return 0;
- set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
- target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
+ is_running = list_empty(&cmd->cmdr_queue_entry);
+ pr_debug("Timing out cmd %u on dev %s that is %s.\n",
+ id, udev->name, is_running ? "inflight" : "queued");
+
+ se_cmd = cmd->se_cmd;
cmd->se_cmd = NULL;
+ if (is_running) {
+ set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
+ /*
+ * target_complete_cmd will translate this to LUN COMM FAILURE
+ */
+ scsi_status = SAM_STAT_CHECK_CONDITION;
+ } else {
+ list_del_init(&cmd->cmdr_queue_entry);
+
+ idr_remove(&udev->commands, id);
+ tcmu_free_cmd(cmd);
+ scsi_status = SAM_STAT_TASK_SET_FULL;
+ }
+ target_complete_cmd(se_cmd, scsi_status);
return 0;
}
@@ -1072,7 +1111,7 @@ static void tcmu_device_timedout(struct timer_list *t)
list_add_tail(&udev->timedout_entry, &timed_out_udevs);
spin_unlock(&timed_out_udevs_lock);
- schedule_work(&tcmu_unmap_work);
+ schedule_delayed_work(&tcmu_unmap_work, 0);
}
static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
@@ -1113,10 +1152,10 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
udev->hba = hba;
udev->cmd_time_out = TCMU_TIME_OUT;
- init_waitqueue_head(&udev->wait_cmdr);
mutex_init(&udev->cmdr_lock);
INIT_LIST_HEAD(&udev->timedout_entry);
+ INIT_LIST_HEAD(&udev->cmdr_queue);
idr_init(&udev->commands);
timer_setup(&udev->timeout, tcmu_device_timedout, 0);
@@ -1129,13 +1168,63 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
return &udev->se_dev;
}
+static bool run_cmdr_queue(struct tcmu_dev *udev)
+{
+ struct tcmu_cmd *tcmu_cmd, *tmp_cmd;
+ LIST_HEAD(cmds);
+ bool drained = true;
+ sense_reason_t scsi_ret;
+ int ret;
+
+ if (list_empty(&udev->cmdr_queue))
+ return true;
+
+ pr_debug("running %s's cmdr queue\n", udev->name);
+
+ list_splice_init(&udev->cmdr_queue, &cmds);
+
+ list_for_each_entry_safe(tcmu_cmd, tmp_cmd, &cmds, cmdr_queue_entry) {
+ list_del_init(&tcmu_cmd->cmdr_queue_entry);
+
+ pr_debug("removing cmd %u on dev %s from queue\n",
+ tcmu_cmd->cmd_id, udev->name);
+
+ ret = queue_cmd_ring(tcmu_cmd, &scsi_ret);
+ if (ret < 0) {
+ pr_debug("cmd %u on dev %s failed with %u\n",
+ tcmu_cmd->cmd_id, udev->name, scsi_ret);
+
+ idr_remove(&udev->commands, tcmu_cmd->cmd_id);
+ /*
+ * Ignore scsi_ret for now. target_complete_cmd
+ * drops it.
+ */
+ target_complete_cmd(tcmu_cmd->se_cmd,
+ SAM_STAT_CHECK_CONDITION);
+ tcmu_free_cmd(tcmu_cmd);
+ } else if (ret > 0) {
+ pr_debug("ran out of space during cmdr queue run\n");
+ /*
+ * cmd was requeued, so just put all cmds back in
+ * the queue
+ */
+ list_splice_tail(&cmds, &udev->cmdr_queue);
+ drained = false;
+ goto done;
+ }
+ }
+done:
+ return drained;
+}
+
static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
{
- struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
+ struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
- mutex_lock(&tcmu_dev->cmdr_lock);
- tcmu_handle_completions(tcmu_dev);
- mutex_unlock(&tcmu_dev->cmdr_lock);
+ mutex_lock(&udev->cmdr_lock);
+ tcmu_handle_completions(udev);
+ run_cmdr_queue(udev);
+ mutex_unlock(&udev->cmdr_lock);
return 0;
}
@@ -1531,7 +1620,6 @@ static int tcmu_configure_device(struct se_device *dev)
udev->data_off = CMDR_SIZE;
udev->data_size = DATA_SIZE;
udev->dbi_thresh = 0; /* Default in Idle state */
- udev->waiting_global = false;
/* Initialise the mailbox of the ring buffer */
mb = udev->mb_addr;
@@ -1977,12 +2065,14 @@ static struct target_backend_ops tcmu_ops = {
.tb_dev_attrib_attrs = NULL,
};
-
static void find_free_blocks(void)
{
struct tcmu_dev *udev;
loff_t off;
- uint32_t start, end, block;
+ u32 start, end, block, total_freed = 0;
+
+ if (atomic_read(&global_db_count) <= TCMU_GLOBAL_MAX_BLOCKS)
+ return;
mutex_lock(&root_udev_mutex);
list_for_each_entry(udev, &root_udev, node) {
@@ -1991,8 +2081,8 @@ static void find_free_blocks(void)
/* Try to complete the finished commands first */
tcmu_handle_completions(udev);
- /* Skip the udevs waiting the global pool or in idle */
- if (udev->waiting_global || !udev->dbi_thresh) {
+ /* Skip the udevs in idle */
+ if (!udev->dbi_thresh) {
mutex_unlock(&udev->cmdr_lock);
continue;
}
@@ -2001,8 +2091,8 @@ static void find_free_blocks(void)
block = find_last_bit(udev->data_bitmap, end);
if (block == udev->dbi_max) {
/*
- * The last bit is dbi_max, so there is
- * no need to shrink any blocks.
+ * The last bit is dbi_max, so it is not possible
+ * reclaim any blocks.
*/
mutex_unlock(&udev->cmdr_lock);
continue;
@@ -2022,30 +2112,15 @@ static void find_free_blocks(void)
/* Release the block pages */
tcmu_blocks_release(&udev->data_blocks, start, end);
mutex_unlock(&udev->cmdr_lock);
- }
- mutex_unlock(&root_udev_mutex);
-}
-static void run_cmdr_queues(void)
-{
- struct tcmu_dev *udev;
-
- /*
- * Try to wake up the udevs who are waiting
- * for the global data block pool.
- */
- mutex_lock(&root_udev_mutex);
- list_for_each_entry(udev, &root_udev, node) {
- mutex_lock(&udev->cmdr_lock);
- if (!udev->waiting_global) {
- mutex_unlock(&udev->cmdr_lock);
- break;
- }
- mutex_unlock(&udev->cmdr_lock);
-
- wake_up(&udev->wait_cmdr);
+ total_freed += end - start;
+ pr_debug("Freed %u blocks (total %u) from %s.\n", end - start,
+ total_freed, udev->name);
}
mutex_unlock(&root_udev_mutex);
+
+ if (atomic_read(&global_db_count) > TCMU_GLOBAL_MAX_BLOCKS)
+ schedule_delayed_work(&tcmu_unmap_work, msecs_to_jiffies(5000));
}
static void check_timedout_devices(void)
@@ -2074,7 +2149,6 @@ static void tcmu_unmap_work_fn(struct work_struct *work)
{
check_timedout_devices();
find_free_blocks();
- run_cmdr_queues();
}
static int __init tcmu_module_init(void)
@@ -2083,7 +2157,7 @@ static int __init tcmu_module_init(void)
BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
- INIT_WORK(&tcmu_unmap_work, tcmu_unmap_work_fn);
+ INIT_DELAYED_WORK(&tcmu_unmap_work, tcmu_unmap_work_fn);
tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
sizeof(struct tcmu_cmd),
@@ -2146,7 +2220,7 @@ out_free_cache:
static void __exit tcmu_module_exit(void)
{
- cancel_work_sync(&tcmu_unmap_work);
+ cancel_delayed_work_sync(&tcmu_unmap_work);
target_backend_unregister(&tcmu_ops);
kfree(tcmu_attrs);
genl_unregister_family(&tcmu_genl_family);

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