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author | Frank Haverkamp <haver@linux.vnet.ibm.com> | 2014-09-10 16:37:53 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-09-23 23:15:47 -0700 |
commit | 1451f414639465995dfc1f820aa1a64723cbd662 (patch) | |
tree | d1983ab9e5d532368ad82261295a78c114fa8514 /drivers/misc/genwqe/card_ddcb.c | |
parent | 08e4906cc29d092ae2da0ff089efe1488e584d3c (diff) | |
download | linux-stable-1451f414639465995dfc1f820aa1a64723cbd662.tar.gz linux-stable-1451f414639465995dfc1f820aa1a64723cbd662.tar.bz2 linux-stable-1451f414639465995dfc1f820aa1a64723cbd662.zip |
GenWQE: Support blocking when DDCB queue is busy
When the GenWQE hardware queue was busy, the driver returned simply
-EBUSY. This caused polling by applications which increased the load
on the already busy system. This change implements the possiblity to
sleep on a waitqueue instead when the DDCB queue is busy. The
requestor is woken up when there is free space on the queue again.
The old way to get -EBUSY is still available if the device is openend
with O_NONBLOCKING. The default is now blocking behavior.
Signed-off-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/misc/genwqe/card_ddcb.c')
-rw-r--r-- | drivers/misc/genwqe/card_ddcb.c | 44 |
1 files changed, 34 insertions, 10 deletions
diff --git a/drivers/misc/genwqe/card_ddcb.c b/drivers/misc/genwqe/card_ddcb.c index 51480e4f8054..6d51e5f08664 100644 --- a/drivers/misc/genwqe/card_ddcb.c +++ b/drivers/misc/genwqe/card_ddcb.c @@ -448,8 +448,10 @@ static int genwqe_check_ddcb_queue(struct genwqe_dev *cd, queue->ddcbs_completed++; queue->ddcbs_in_flight--; - /* wake up process waiting for this DDCB */ + /* wake up process waiting for this DDCB, and + processes on the busy queue */ wake_up_interruptible(&queue->ddcb_waitqs[queue->ddcb_act]); + wake_up_interruptible(&queue->busy_waitq); pick_next_one: queue->ddcb_act = (queue->ddcb_act + 1) % queue->ddcb_max; @@ -745,14 +747,16 @@ int genwqe_init_debug_data(struct genwqe_dev *cd, struct genwqe_debug_data *d) /** * __genwqe_enqueue_ddcb() - Enqueue a DDCB - * @cd: pointer to genwqe device descriptor - * @req: pointer to DDCB execution request + * @cd: pointer to genwqe device descriptor + * @req: pointer to DDCB execution request + * @f_flags: file mode: blocking, non-blocking * * Return: 0 if enqueuing succeeded * -EIO if card is unusable/PCIe problems * -EBUSY if enqueuing failed */ -int __genwqe_enqueue_ddcb(struct genwqe_dev *cd, struct ddcb_requ *req) +int __genwqe_enqueue_ddcb(struct genwqe_dev *cd, struct ddcb_requ *req, + unsigned int f_flags) { struct ddcb *pddcb; unsigned long flags; @@ -760,6 +764,7 @@ int __genwqe_enqueue_ddcb(struct genwqe_dev *cd, struct ddcb_requ *req) struct pci_dev *pci_dev = cd->pci_dev; u16 icrc; + retry: if (cd->card_state != GENWQE_CARD_USED) { printk_ratelimited(KERN_ERR "%s %s: [%s] Card is unusable/PCIe problem Req#%d\n", @@ -785,9 +790,24 @@ int __genwqe_enqueue_ddcb(struct genwqe_dev *cd, struct ddcb_requ *req) pddcb = get_next_ddcb(cd, queue, &req->num); /* get ptr and num */ if (pddcb == NULL) { + int rc; + spin_unlock_irqrestore(&queue->ddcb_lock, flags); - queue->busy++; - return -EBUSY; + + if (f_flags & O_NONBLOCK) { + queue->return_on_busy++; + return -EBUSY; + } + + queue->wait_on_busy++; + rc = wait_event_interruptible(queue->busy_waitq, + queue_free_ddcbs(queue) != 0); + dev_dbg(&pci_dev->dev, "[%s] waiting for free DDCB: rc=%d\n", + __func__, rc); + if (rc == -ERESTARTSYS) + return rc; /* interrupted by a signal */ + + goto retry; } if (queue->ddcb_req[req->num] != NULL) { @@ -890,9 +910,11 @@ int __genwqe_enqueue_ddcb(struct genwqe_dev *cd, struct ddcb_requ *req) * __genwqe_execute_raw_ddcb() - Setup and execute DDCB * @cd: pointer to genwqe device descriptor * @req: user provided DDCB request + * @f_flags: file mode: blocking, non-blocking */ int __genwqe_execute_raw_ddcb(struct genwqe_dev *cd, - struct genwqe_ddcb_cmd *cmd) + struct genwqe_ddcb_cmd *cmd, + unsigned int f_flags) { int rc = 0; struct pci_dev *pci_dev = cd->pci_dev; @@ -908,7 +930,7 @@ int __genwqe_execute_raw_ddcb(struct genwqe_dev *cd, __func__, cmd->asiv_length); return -EINVAL; } - rc = __genwqe_enqueue_ddcb(cd, req); + rc = __genwqe_enqueue_ddcb(cd, req, f_flags); if (rc != 0) return rc; @@ -1014,7 +1036,8 @@ static int setup_ddcb_queue(struct genwqe_dev *cd, struct ddcb_queue *queue) queue->ddcbs_in_flight = 0; /* statistics */ queue->ddcbs_max_in_flight = 0; queue->ddcbs_completed = 0; - queue->busy = 0; + queue->return_on_busy = 0; + queue->wait_on_busy = 0; queue->ddcb_seq = 0x100; /* start sequence number */ queue->ddcb_max = genwqe_ddcb_max; /* module parameter */ @@ -1054,7 +1077,7 @@ static int setup_ddcb_queue(struct genwqe_dev *cd, struct ddcb_queue *queue) queue->ddcb_next = 0; /* queue is empty */ spin_lock_init(&queue->ddcb_lock); - init_waitqueue_head(&queue->ddcb_waitq); + init_waitqueue_head(&queue->busy_waitq); val64 = ((u64)(queue->ddcb_max - 1) << 8); /* lastptr */ __genwqe_writeq(cd, queue->IO_QUEUE_CONFIG, 0x07); /* iCRC/vCRC */ @@ -1302,6 +1325,7 @@ static int queue_wake_up_all(struct genwqe_dev *cd) for (i = 0; i < queue->ddcb_max; i++) wake_up_interruptible(&queue->ddcb_waitqs[queue->ddcb_act]); + wake_up_interruptible(&queue->busy_waitq); spin_unlock_irqrestore(&queue->ddcb_lock, flags); return 0; |