From 6fbb2de5c960e4d5f769bb0bfb958e306ccc83ee Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Thu, 17 Aug 2017 13:13:27 -0700 Subject: [PATCH] skd: Convert several per-device scalar variables into atomics Convert the per-device scalar variables that are protected by the queue lock into atomics such that it becomes safe to access these variables without holding the queue lock. Signed-off-by: Bart Van Assche Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Johannes Thumshirn Signed-off-by: Jens Axboe --- drivers/block/skd_main.c | 68 ++++++++++++++++++++++------------------ 1 file changed, 37 insertions(+), 31 deletions(-) diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c index 35343fbf4144..4b92d711d2d3 100644 --- a/drivers/block/skd_main.c +++ b/drivers/block/skd_main.c @@ -243,7 +243,7 @@ struct skd_device { enum skd_drvr_state state; u32 drive_state; - u32 in_flight; + atomic_t in_flight; u32 cur_max_queue_depth; u32 queue_low_water_mark; u32 dev_max_queue_depth; @@ -251,8 +251,8 @@ struct skd_device { u32 num_fitmsg_context; u32 num_req_context; - u32 timeout_slot[SKD_N_TIMEOUT_SLOT]; - u32 timeout_stamp; + atomic_t timeout_slot[SKD_N_TIMEOUT_SLOT]; + atomic_t timeout_stamp; struct skd_fitmsg_context *skmsg_table; struct skd_request_context *skreq_table; @@ -517,7 +517,8 @@ static void skd_request_fn(struct request_queue *q) } if (blk_queue_stopped(skdev->queue)) { - if (skdev->in_flight >= skdev->queue_low_water_mark) + if (atomic_read(&skdev->in_flight) >= + skdev->queue_low_water_mark) /* There is still some kind of shortage */ return; @@ -559,9 +560,11 @@ static void skd_request_fn(struct request_queue *q) /* At this point we know there is a request */ /* Are too many requets already in progress? */ - if (skdev->in_flight >= skdev->cur_max_queue_depth) { + if (atomic_read(&skdev->in_flight) >= + skdev->cur_max_queue_depth) { dev_dbg(&skdev->pdev->dev, "qdepth %d, limit %d\n", - skdev->in_flight, skdev->cur_max_queue_depth); + atomic_read(&skdev->in_flight), + skdev->cur_max_queue_depth); break; } @@ -647,12 +650,12 @@ static void skd_request_fn(struct request_queue *q) * Update the active request counts. * Capture the timeout timestamp. */ - skreq->timeout_stamp = skdev->timeout_stamp; + skreq->timeout_stamp = atomic_read(&skdev->timeout_stamp); timo_slot = skreq->timeout_stamp & SKD_TIMEOUT_SLOT_MASK; - skdev->timeout_slot[timo_slot]++; - skdev->in_flight++; + 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, - skdev->in_flight); + atomic_read(&skdev->in_flight)); /* * If the FIT msg buffer is full send it. @@ -805,22 +808,24 @@ static void skd_timer_tick(ulong arg) skd_timer_tick_not_online(skdev); goto timer_func_out; } - skdev->timeout_stamp++; - timo_slot = skdev->timeout_stamp & SKD_TIMEOUT_SLOT_MASK; + 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 (skdev->timeout_slot[timo_slot] == 0) + 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", - skdev->timeout_slot[timo_slot], skdev->in_flight); + atomic_read(&skdev->timeout_slot[timo_slot]), + atomic_read(&skdev->in_flight)); dev_err(&skdev->pdev->dev, "Overdue IOs (%d), busy %d\n", - skdev->timeout_slot[timo_slot], skdev->in_flight); + 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; @@ -900,10 +905,10 @@ static void skd_timer_tick_not_online(struct skd_device *skdev) dev_dbg(&skdev->pdev->dev, "draining busy [%d] tick[%d] qdb[%d] tmls[%d]\n", skdev->timo_slot, skdev->timer_countdown, - skdev->in_flight, - skdev->timeout_slot[skdev->timo_slot]); + 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 (skdev->timeout_slot[skdev->timo_slot] == 0) { + 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; @@ -1310,7 +1315,7 @@ static void skd_send_fitmsg(struct skd_device *skdev, u64 qcmd; dev_dbg(&skdev->pdev->dev, "dma address 0x%llx, busy=%d\n", - skmsg->mb_dma_address, skdev->in_flight); + skmsg->mb_dma_address, atomic_read(&skdev->in_flight)); dev_dbg(&skdev->pdev->dev, "msg_buf %p\n", skmsg->msg_buf); qcmd = skmsg->mb_dma_address; @@ -1550,12 +1555,12 @@ static void skd_release_skreq(struct skd_device *skdev, * Decrease the number of active requests. * Also decrements the count in the timeout slot. */ - SKD_ASSERT(skdev->in_flight > 0); - skdev->in_flight -= 1; + SKD_ASSERT(atomic_read(&skdev->in_flight) > 0); + atomic_dec(&skdev->in_flight); timo_slot = skreq->timeout_stamp & SKD_TIMEOUT_SLOT_MASK; - SKD_ASSERT(skdev->timeout_slot[timo_slot] > 0); - skdev->timeout_slot[timo_slot] -= 1; + SKD_ASSERT(atomic_read(&skdev->timeout_slot[timo_slot]) > 0); + atomic_dec(&skdev->timeout_slot[timo_slot]); /* * Reset backpointer @@ -1615,8 +1620,8 @@ static int skd_isr_completion_posted(struct skd_device *skdev, dev_dbg(&skdev->pdev->dev, "cycle=%d ix=%d got cycle=%d cmdctxt=0x%x stat=%d busy=%d rbytes=0x%x proto=%d\n", skdev->skcomp_cycle, skdev->skcomp_ix, cmp_cycle, - cmp_cntxt, cmp_status, skdev->in_flight, cmp_bytes, - skdev->proto_ver); + cmp_cntxt, cmp_status, atomic_read(&skdev->in_flight), + cmp_bytes, skdev->proto_ver); if (cmp_cycle != skdev->skcomp_cycle) { dev_dbg(&skdev->pdev->dev, "end of completions\n"); @@ -1707,8 +1712,8 @@ static int skd_isr_completion_posted(struct skd_device *skdev, } } - if ((skdev->state == SKD_DRVR_STATE_PAUSING) - && (skdev->in_flight) == 0) { + if (skdev->state == SKD_DRVR_STATE_PAUSING && + atomic_read(&skdev->in_flight) == 0) { skdev->state = SKD_DRVR_STATE_PAUSED; wake_up_interruptible(&skdev->waitq); } @@ -2053,9 +2058,9 @@ static void skd_recover_requests(struct skd_device *skdev) } for (i = 0; i < SKD_N_TIMEOUT_SLOT; i++) - skdev->timeout_slot[i] = 0; + atomic_set(&skdev->timeout_slot[i], 0); - skdev->in_flight = 0; + atomic_set(&skdev->in_flight, 0); } static void skd_isr_msg_from_dev(struct skd_device *skdev) @@ -3714,10 +3719,11 @@ static void skd_log_skdev(struct skd_device *skdev, const char *event) skd_drive_state_to_str(skdev->drive_state), skdev->drive_state, skd_skdev_state_to_str(skdev->state), skdev->state); dev_dbg(&skdev->pdev->dev, " busy=%d limit=%d dev=%d lowat=%d\n", - skdev->in_flight, skdev->cur_max_queue_depth, + 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", - skdev->timeout_stamp, skdev->skcomp_cycle, skdev->skcomp_ix); + atomic_read(&skdev->timeout_stamp), skdev->skcomp_cycle, + skdev->skcomp_ix); } static void skd_log_skreq(struct skd_device *skdev,