skd: Switch to block layer timeout mechanism

Remove the timeout slot variables and rely on the block layer to
detect request timeouts.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c
index 3590f9a775aef18f5cc8c2dd466da8147ec75d35..a982de2014ccd8fc234a42d1a44c6a1d3123527a 100644 (file)
--- a/drivers/block/skd_main.c
+++ b/drivers/block/skd_main.c
@@ -105,9 +105,6 @@ MODULE_VERSION(DRV_VERSION "-" DRV_BUILD_ID);
 #define SKD_ID_SLOT_MASK        0x00FFu
 #define SKD_ID_SLOT_AND_TABLE_MASK 0x03FFu
 
-#define SKD_N_TIMEOUT_SLOT      4u
-#define SKD_TIMEOUT_SLOT_MASK   3u
-
 #define SKD_N_MAX_SECTORS 2048u
 
 #define SKD_MAX_RETRIES 2u
@@ -125,7 +122,6 @@ enum skd_drvr_state {
        SKD_DRVR_STATE_ONLINE,
        SKD_DRVR_STATE_PAUSING,
        SKD_DRVR_STATE_PAUSED,
-       SKD_DRVR_STATE_DRAINING_TIMEOUT,
        SKD_DRVR_STATE_RESTARTING,
        SKD_DRVR_STATE_RESUMING,
        SKD_DRVR_STATE_STOPPING,
@@ -142,7 +138,6 @@ enum skd_drvr_state {
 #define SKD_WAIT_BOOT_TIMO      SKD_TIMER_SECONDS(90u)
 #define SKD_STARTING_TIMO       SKD_TIMER_SECONDS(8u)
 #define SKD_RESTARTING_TIMO     SKD_TIMER_MINUTES(4u)
-#define SKD_DRAINING_TIMO       SKD_TIMER_SECONDS(6u)
 #define SKD_BUSY_TIMO           SKD_TIMER_MINUTES(20u)
 #define SKD_STARTED_BUSY_TIMO   SKD_TIMER_SECONDS(60u)
 #define SKD_START_WAIT_SECONDS  90u
@@ -185,7 +180,6 @@ struct skd_request_context {
 
        u8 flush_cmd;
 
-       u32 timeout_stamp;
        enum dma_data_direction data_dir;
        struct scatterlist *sg;
        u32 n_sg;
@@ -252,8 +246,6 @@ struct skd_device {
        u32 num_fitmsg_context;
        u32 num_req_context;
 
-       atomic_t timeout_slot[SKD_N_TIMEOUT_SLOT];
-       atomic_t timeout_stamp;
        struct skd_fitmsg_context *skmsg_table;
 
        struct skd_special_context internal_skspcl;
@@ -464,7 +456,6 @@ static bool skd_fail_all(struct request_queue *q)
        case SKD_DRVR_STATE_BUSY:
        case SKD_DRVR_STATE_BUSY_IMMINENT:
        case SKD_DRVR_STATE_BUSY_ERASE:
-       case SKD_DRVR_STATE_DRAINING_TIMEOUT:
                return false;
 
        case SKD_DRVR_STATE_BUSY_SANITIZE:
@@ -492,7 +483,6 @@ static void skd_process_request(struct request *req, bool last)
        u32 count;
        int data_dir;
        __be64 be_dmaa;
-       u32 timo_slot;
        int flush, fua;
 
        WARN_ONCE(tag >= skd_max_queue_depth, "%#x > %#x (nr_requests = %lu)\n",
@@ -577,13 +567,6 @@ static void skd_process_request(struct request *req, bool last)
        skmsg->length += sizeof(struct skd_scsi_request);
        fmh->num_protocol_cmds_coalesced++;
 
-       /*
-        * Update the active request counts.
-        * Capture the timeout timestamp.
-        */
-       skreq->timeout_stamp = atomic_read(&skdev->timeout_stamp);
-       timo_slot = skreq->timeout_stamp & SKD_TIMEOUT_SLOT_MASK;
-       atomic_inc(&skdev->timeout_slot[timo_slot]);
        atomic_inc(&skdev->in_flight);
        dev_dbg(&skdev->pdev->dev, "req=0x%x busy=%d\n", skreq->id,
                atomic_read(&skdev->in_flight));
@@ -617,6 +600,16 @@ static blk_status_t skd_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
        return BLK_STS_OK;
 }
 
+static enum blk_eh_timer_return skd_timed_out(struct request *req)
+{
+       struct skd_device *skdev = req->q->queuedata;
+
+       dev_err(&skdev->pdev->dev, "request with tag %#x timed out\n",
+               blk_mq_unique_tag(req));
+
+       return BLK_EH_HANDLED;
+}
+
 static void skd_end_request(struct skd_device *skdev, struct request *req,
                            blk_status_t error)
 {
@@ -635,6 +628,18 @@ static void skd_end_request(struct skd_device *skdev, struct request *req,
        blk_mq_end_request(req, error);
 }
 
+/* Only called in case of a request timeout */
+static void skd_softirq_done(struct request *req)
+{
+       struct skd_device *skdev = req->q->queuedata;
+       struct skd_request_context *skreq = blk_mq_rq_to_pdu(req);
+       unsigned long flags;
+
+       spin_lock_irqsave(&skdev->lock, flags);
+       skd_end_request(skdev, blk_mq_rq_from_pdu(skreq), BLK_STS_TIMEOUT);
+       spin_unlock_irqrestore(&skdev->lock, flags);
+}
+
 static bool skd_preop_sg_list(struct skd_device *skdev,
                             struct skd_request_context *skreq)
 {
@@ -733,8 +738,6 @@ static void skd_start_queue(struct work_struct *work)
 static void skd_timer_tick(ulong arg)
 {
        struct skd_device *skdev = (struct skd_device *)arg;
-
-       u32 timo_slot;
        unsigned long reqflags;
        u32 state;
 
@@ -751,35 +754,9 @@ static void skd_timer_tick(ulong arg)
        if (state != skdev->drive_state)
                skd_isr_fwstate(skdev);
 
-       if (skdev->state != SKD_DRVR_STATE_ONLINE) {
+       if (skdev->state != SKD_DRVR_STATE_ONLINE)
                skd_timer_tick_not_online(skdev);
-               goto timer_func_out;
-       }
-       timo_slot = atomic_inc_return(&skdev->timeout_stamp) &
-               SKD_TIMEOUT_SLOT_MASK;
-
-       /*
-        * All requests that happened during the previous use of
-        * this slot should be done by now. The previous use was
-        * over 7 seconds ago.
-        */
-       if (atomic_read(&skdev->timeout_slot[timo_slot]) == 0)
-               goto timer_func_out;
-
-       /* Something is overdue */
-       dev_dbg(&skdev->pdev->dev, "found %d timeouts, draining busy=%d\n",
-               atomic_read(&skdev->timeout_slot[timo_slot]),
-               atomic_read(&skdev->in_flight));
-       dev_err(&skdev->pdev->dev, "Overdue IOs (%d), busy %d\n",
-               atomic_read(&skdev->timeout_slot[timo_slot]),
-               atomic_read(&skdev->in_flight));
-
-       skdev->timer_countdown = SKD_DRAINING_TIMO;
-       skdev->state = SKD_DRVR_STATE_DRAINING_TIMEOUT;
-       skdev->timo_slot = timo_slot;
-       blk_stop_queue(skdev->queue);
 
-timer_func_out:
        mod_timer(&skdev->timer, (jiffies + HZ));
 
        spin_unlock_irqrestore(&skdev->lock, reqflags);
@@ -848,27 +825,6 @@ static void skd_timer_tick_not_online(struct skd_device *skdev)
        case SKD_DRVR_STATE_PAUSED:
                break;
 
-       case SKD_DRVR_STATE_DRAINING_TIMEOUT:
-               dev_dbg(&skdev->pdev->dev,
-                       "draining busy [%d] tick[%d] qdb[%d] tmls[%d]\n",
-                       skdev->timo_slot, skdev->timer_countdown,
-                       atomic_read(&skdev->in_flight),
-                       atomic_read(&skdev->timeout_slot[skdev->timo_slot]));
-               /* if the slot has cleared we can let the I/O continue */
-               if (atomic_read(&skdev->timeout_slot[skdev->timo_slot]) == 0) {
-                       dev_dbg(&skdev->pdev->dev,
-                               "Slot drained, starting queue.\n");
-                       skdev->state = SKD_DRVR_STATE_ONLINE;
-                       blk_start_queue(skdev->queue);
-                       return;
-               }
-               if (skdev->timer_countdown > 0) {
-                       skdev->timer_countdown--;
-                       return;
-               }
-               skd_restart_device(skdev);
-               break;
-
        case SKD_DRVR_STATE_RESTARTING:
                if (skdev->timer_countdown > 0) {
                        skdev->timer_countdown--;
@@ -1495,8 +1451,6 @@ static void skd_resolve_req_exception(struct skd_device *skdev,
 static void skd_release_skreq(struct skd_device *skdev,
                              struct skd_request_context *skreq)
 {
-       u32 timo_slot;
-
        /*
         * Decrease the number of active requests.
         * Also decrements the count in the timeout slot.
@@ -1504,10 +1458,6 @@ static void skd_release_skreq(struct skd_device *skdev,
        SKD_ASSERT(atomic_read(&skdev->in_flight) > 0);
        atomic_dec(&skdev->in_flight);
 
-       timo_slot = skreq->timeout_stamp & SKD_TIMEOUT_SLOT_MASK;
-       SKD_ASSERT(atomic_read(&skdev->timeout_slot[timo_slot]) > 0);
-       atomic_dec(&skdev->timeout_slot[timo_slot]);
-
        /*
         * Reclaim the skd_request_context
         */
@@ -1620,7 +1570,6 @@ static int skd_isr_completion_posted(struct skd_device *skdev,
                if (skreq->n_sg > 0)
                        skd_postop_sg_list(skdev, skreq);
 
-               /* Mark the FIT msg and timeout slot as free. */
                skd_release_skreq(skdev, skreq);
 
                /*
@@ -1979,13 +1928,8 @@ static void skd_recover_request(struct request *req, void *data, bool reserved)
 
 static void skd_recover_requests(struct skd_device *skdev)
 {
-       int i;
-
        blk_mq_tagset_busy_iter(&skdev->tag_set, skd_recover_request, skdev);
 
-       for (i = 0; i < SKD_N_TIMEOUT_SLOT; i++)
-               atomic_set(&skdev->timeout_slot[i], 0);
-
        atomic_set(&skdev->in_flight, 0);
 }
 
@@ -2917,6 +2861,10 @@ static int skd_cons_disk(struct skd_device *skdev)
        queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
        queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
 
+       blk_queue_rq_timeout(q, 8 * HZ);
+       blk_queue_rq_timed_out(q, skd_timed_out);
+       blk_queue_softirq_done(q, skd_softirq_done);
+
        spin_lock_irqsave(&skdev->lock, flags);
        dev_dbg(&skdev->pdev->dev, "stopping queue\n");
        blk_mq_stop_hw_queues(skdev->queue);
@@ -3561,8 +3509,6 @@ const char *skd_skdev_state_to_str(enum skd_drvr_state state)
                return "PAUSING";
        case SKD_DRVR_STATE_PAUSED:
                return "PAUSED";
-       case SKD_DRVR_STATE_DRAINING_TIMEOUT:
-               return "DRAINING_TIMEOUT";
        case SKD_DRVR_STATE_RESTARTING:
                return "RESTARTING";
        case SKD_DRVR_STATE_RESUMING:
@@ -3616,9 +3562,8 @@ static void skd_log_skdev(struct skd_device *skdev, const char *event)
        dev_dbg(&skdev->pdev->dev, "  busy=%d limit=%d dev=%d lowat=%d\n",
                atomic_read(&skdev->in_flight), skdev->cur_max_queue_depth,
                skdev->dev_max_queue_depth, skdev->queue_low_water_mark);
-       dev_dbg(&skdev->pdev->dev, "  timestamp=0x%x cycle=%d cycle_ix=%d\n",
-               atomic_read(&skdev->timeout_stamp), skdev->skcomp_cycle,
-               skdev->skcomp_ix);
+       dev_dbg(&skdev->pdev->dev, "  cycle=%d cycle_ix=%d\n",
+               skdev->skcomp_cycle, skdev->skcomp_ix);
 }
 
 static void skd_log_skreq(struct skd_device *skdev,
@@ -3632,8 +3577,8 @@ static void skd_log_skreq(struct skd_device *skdev,
        dev_dbg(&skdev->pdev->dev, "  state=%s(%d) id=0x%04x fitmsg=0x%04x\n",
                skd_skreq_state_to_str(skreq->state), skreq->state, skreq->id,
                skreq->fitmsg_id);
-       dev_dbg(&skdev->pdev->dev, "  timo=0x%x sg_dir=%d n_sg=%d\n",
-               skreq->timeout_stamp, skreq->data_dir, skreq->n_sg);
+       dev_dbg(&skdev->pdev->dev, "  sg_dir=%d n_sg=%d\n",
+               skreq->data_dir, skreq->n_sg);
 
        dev_dbg(&skdev->pdev->dev,
                "req=%p lba=%u(0x%x) count=%u(0x%x) dir=%d\n", req, lba, lba,