@@ -218,7 +218,7 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
/*
* 1024 is big enough for saturating the fast scsi LUN now
*/
-static int scsi_device_max_queue_depth(struct scsi_device *sdev)
+int scsi_device_max_queue_depth(struct scsi_device *sdev)
{
return max_t(int, sdev->host->can_queue, 1024);
}
@@ -242,6 +242,8 @@ int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
if (sdev->request_queue)
blk_set_queue_depth(sdev->request_queue, depth);
+ sbitmap_resize(&sdev->budget_map, sdev->queue_depth);
+
return sdev->queue_depth;
}
EXPORT_SYMBOL(scsi_change_queue_depth);
@@ -328,7 +328,7 @@ void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
if (starget->can_queue > 0)
atomic_dec(&starget->target_busy);
- atomic_dec(&sdev->device_busy);
+ sbitmap_put(&sdev->budget_map, cmd->budget_token);
cmd->budget_token = -1;
}
@@ -1256,19 +1256,20 @@ scsi_device_state_check(struct scsi_device *sdev, struct request *req)
}
/*
- * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
- * return 0.
- *
- * Called with the queue_lock held.
+ * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
+ * and return the token else return -1.
*/
static inline int scsi_dev_queue_ready(struct request_queue *q,
struct scsi_device *sdev)
{
- unsigned int busy;
+ int token;
- busy = atomic_inc_return(&sdev->device_busy) - 1;
+ token = sbitmap_get(&sdev->budget_map);
if (atomic_read(&sdev->device_blocked)) {
- if (busy)
+ if (token < 0)
+ goto out;
+
+ if (scsi_device_busy(sdev) > 1)
goto out_dec;
/*
@@ -1280,13 +1281,12 @@ static inline int scsi_dev_queue_ready(struct request_queue *q,
"unblocking device at zero depth\n"));
}
- if (busy >= sdev->queue_depth)
- goto out_dec;
-
- return 1;
+ return token;
out_dec:
- atomic_dec(&sdev->device_busy);
- return 0;
+ if (token >= 0)
+ sbitmap_put(&sdev->budget_map, token);
+out:
+ return -1;
}
/*
@@ -1611,15 +1611,16 @@ static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
{
struct scsi_device *sdev = q->queuedata;
- atomic_dec(&sdev->device_busy);
+ sbitmap_put(&sdev->budget_map, budget_token);
}
static int scsi_mq_get_budget(struct request_queue *q)
{
struct scsi_device *sdev = q->queuedata;
+ int token = scsi_dev_queue_ready(q, sdev);
- if (scsi_dev_queue_ready(q, sdev))
- return 0;
+ if (token >= 0)
+ return token;
atomic_inc(&sdev->restarts);
@@ -5,6 +5,7 @@
#include <linux/device.h>
#include <linux/async.h>
#include <scsi/scsi_device.h>
+#include <linux/sbitmap.h>
struct request_queue;
struct request;
@@ -182,6 +183,8 @@ static inline void scsi_dh_add_device(struct scsi_device *sdev) { }
static inline void scsi_dh_release_device(struct scsi_device *sdev) { }
#endif
+extern int scsi_device_max_queue_depth(struct scsi_device *sdev);
+
/*
* internal scsi timeout functions: for use by mid-layer and transport
* classes.
@@ -215,6 +215,7 @@ static void scsi_unlock_floptical(struct scsi_device *sdev,
static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
u64 lun, void *hostdata)
{
+ unsigned int depth;
struct scsi_device *sdev;
int display_failure_msg = 1, ret;
struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
@@ -276,8 +277,25 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
WARN_ON_ONCE(!blk_get_queue(sdev->request_queue));
sdev->request_queue->queuedata = sdev;
- scsi_change_queue_depth(sdev, sdev->host->cmd_per_lun ?
- sdev->host->cmd_per_lun : 1);
+ depth = sdev->host->cmd_per_lun ?: 1;
+
+ /*
+ * Use .can_queue as budget map's depth because we have to
+ * support adjusting queue depth from sysfs. Meantime use
+ * default device queue depth to figure out sbitmap shift
+ * since we use this queue depth most of times.
+ */
+ if (sbitmap_init_node(&sdev->budget_map,
+ scsi_device_max_queue_depth(sdev),
+ sbitmap_calculate_shift(depth),
+ GFP_KERNEL, sdev->request_queue->node,
+ false, true)) {
+ put_device(&starget->dev);
+ kfree(sdev);
+ goto out;
+ }
+
+ scsi_change_queue_depth(sdev, depth);
scsi_sysfs_device_initialize(sdev);
@@ -979,6 +997,7 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
scsi_attach_vpd(sdev);
sdev->max_queue_depth = sdev->queue_depth;
+ WARN_ON_ONCE(sdev->max_queue_depth > sdev->budget_map.depth);
sdev->sdev_bflags = *bflags;
/*
@@ -477,6 +477,8 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
/* NULL queue means the device can't be used */
sdev->request_queue = NULL;
+ sbitmap_free(&sdev->budget_map);
+
mutex_lock(&sdev->inquiry_mutex);
vpd_pg0 = rcu_replace_pointer(sdev->vpd_pg0, vpd_pg0,
lockdep_is_held(&sdev->inquiry_mutex));
@@ -8,6 +8,7 @@
#include <linux/blkdev.h>
#include <scsi/scsi.h>
#include <linux/atomic.h>
+#include <linux/sbitmap.h>
struct device;
struct request_queue;
@@ -106,7 +107,7 @@ struct scsi_device {
struct list_head siblings; /* list of all devices on this host */
struct list_head same_target_siblings; /* just the devices sharing same target id */
- atomic_t device_busy; /* commands actually active on LLDD */
+ struct sbitmap budget_map;
atomic_t device_blocked; /* Device returned QUEUE_FULL. */
atomic_t restarts;
@@ -592,7 +593,7 @@ static inline int scsi_device_supports_vpd(struct scsi_device *sdev)
static inline int scsi_device_busy(struct scsi_device *sdev)
{
- return atomic_read(&sdev->device_busy);
+ return sbitmap_weight(&sdev->budget_map);
}
#define MODULE_ALIAS_SCSI_DEVICE(type) \