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Commit 1451f414 authored by Frank Haverkamp's avatar Frank Haverkamp Committed by Greg Kroah-Hartman
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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: default avatarFrank Haverkamp <haver@linux.vnet.ibm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 08e4906c

drivers/misc/genwqe/card_base.h

+11 −6
Original line number Diff line number Diff line
@@ -201,7 +201,8 @@ static inline void genwqe_mapping_init(struct dma_mapping *m, 
 * @ddcb_seq:          Sequence number of last DDCB

 * @ddcbs_in_flight:   Currently enqueued DDCBs

 * @ddcbs_completed:   Number of already completed DDCBs

 * @busy:              Number of -EBUSY returns

 * @return_on_busy:    Number of -EBUSY returns on full queue

 * @wait_on_busy:      Number of waits on full queue

 * @ddcb_daddr:        DMA address of first DDCB in the queue

 * @ddcb_vaddr:        Kernel virtual address of first DDCB in the queue

 * @ddcb_req:          Associated requests (one per DDCB)
@@ -218,7 +219,8 @@ struct ddcb_queue { 
	unsigned int ddcbs_in_flight;	/* number of ddcbs in processing */

	unsigned int ddcbs_completed;

	unsigned int ddcbs_max_in_flight;

	unsigned int busy;		/* how many times -EBUSY? */

	unsigned int return_on_busy;    /* how many times -EBUSY? */

	unsigned int wait_on_busy;



	dma_addr_t ddcb_daddr;		/* DMA address */

	struct ddcb *ddcb_vaddr;	/* kernel virtual addr for DDCBs */
@@ -226,7 +228,7 @@ struct ddcb_queue { 
	wait_queue_head_t *ddcb_waitqs; /* waitqueue per ddcb */



	spinlock_t ddcb_lock;		/* exclusive access to queue */

	wait_queue_head_t ddcb_waitq;	/* wait for ddcb processing */

	wait_queue_head_t busy_waitq;   /* wait for ddcb processing */



	/* registers or the respective queue to be used */

	u32 IO_QUEUE_CONFIG;
@@ -508,7 +510,7 @@ static inline bool dma_mapping_used(struct dma_mapping *m) 
 * buildup and teardown.

 */

int  __genwqe_execute_ddcb(struct genwqe_dev *cd,

			   struct genwqe_ddcb_cmd *cmd);

			   struct genwqe_ddcb_cmd *cmd, unsigned int f_flags);



/**

 * __genwqe_execute_raw_ddcb() - Execute DDCB request without addr translation
@@ -520,9 +522,12 @@ int __genwqe_execute_ddcb(struct genwqe_dev *cd, 
 * modification.

 */

int  __genwqe_execute_raw_ddcb(struct genwqe_dev *cd,

			       struct genwqe_ddcb_cmd *cmd);

			       struct genwqe_ddcb_cmd *cmd,

			       unsigned int f_flags);

int  __genwqe_enqueue_ddcb(struct genwqe_dev *cd,

			   struct ddcb_requ *req,

			   unsigned int f_flags);



int  __genwqe_enqueue_ddcb(struct genwqe_dev *cd, struct ddcb_requ *req);

int  __genwqe_wait_ddcb(struct genwqe_dev *cd, struct ddcb_requ *req);

int  __genwqe_purge_ddcb(struct genwqe_dev *cd, struct ddcb_requ *req);

drivers/misc/genwqe/card_ddcb.c

+34 −10
Original line number Diff line number Diff line
@@ -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;
@@ -747,12 +749,14 @@ 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

 * @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",
@@ -785,11 +790,26 @@ 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++;



		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) {

		spin_unlock_irqrestore(&queue->ddcb_lock, flags);
@@ -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;

drivers/misc/genwqe/card_debugfs.c

+4 −2
Original line number Diff line number Diff line
@@ -244,14 +244,16 @@ static int genwqe_ddcb_info_show(struct seq_file *s, void *unused) 
		   "  ddcbs_in_flight:     %u\n"

		   "  ddcbs_max_in_flight: %u\n"

		   "  ddcbs_completed:     %u\n"

		   "  busy:                %u\n"

		   "  return_on_busy:      %u\n"

		   "  wait_on_busy:        %u\n"

		   "  irqs_processed:      %u\n",

		   queue->ddcb_max, (long long)queue->ddcb_daddr,

		   (long long)queue->ddcb_daddr +

		   (queue->ddcb_max * DDCB_LENGTH),

		   (long long)queue->ddcb_vaddr, queue->ddcbs_in_flight,

		   queue->ddcbs_max_in_flight, queue->ddcbs_completed,

		   queue->busy, cd->irqs_processed);

		   queue->return_on_busy, queue->wait_on_busy,

		   cd->irqs_processed);



	/* Hardware State */

	seq_printf(s, "  0x%08x 0x%016llx IO_QUEUE_CONFIG\n"

drivers/misc/genwqe/card_dev.c

+8 −4
Original line number Diff line number Diff line
@@ -516,6 +516,7 @@ static int do_flash_update(struct genwqe_file *cfile, 
	u32 crc;

	u8 cmdopts;

	struct genwqe_dev *cd = cfile->cd;

	struct file *filp = cfile->filp;

	struct pci_dev *pci_dev = cd->pci_dev;



	if ((load->size & 0x3) != 0)
@@ -610,7 +611,7 @@ static int do_flash_update(struct genwqe_file *cfile, 
		/* For Genwqe5 we get back the calculated CRC */

		*(u64 *)&req->asv[0] = 0ULL;			/* 0x80 */



		rc = __genwqe_execute_raw_ddcb(cd, req);

		rc = __genwqe_execute_raw_ddcb(cd, req, filp->f_flags);



		load->retc = req->retc;

		load->attn = req->attn;
@@ -650,6 +651,7 @@ static int do_flash_read(struct genwqe_file *cfile, 
	u8 *xbuf;

	u8 cmdopts;

	struct genwqe_dev *cd = cfile->cd;

	struct file *filp = cfile->filp;

	struct pci_dev *pci_dev = cd->pci_dev;

	struct genwqe_ddcb_cmd *cmd;
@@ -727,7 +729,7 @@ static int do_flash_read(struct genwqe_file *cfile, 
		/* we only get back the calculated CRC */

		*(u64 *)&cmd->asv[0] = 0ULL;	/* 0x80 */



		rc = __genwqe_execute_raw_ddcb(cd, cmd);

		rc = __genwqe_execute_raw_ddcb(cd, cmd, filp->f_flags);



		load->retc = cmd->retc;

		load->attn = cmd->attn;
@@ -988,13 +990,14 @@ static int genwqe_execute_ddcb(struct genwqe_file *cfile, 
{

	int rc;

	struct genwqe_dev *cd = cfile->cd;

	struct file *filp = cfile->filp;

	struct ddcb_requ *req = container_of(cmd, struct ddcb_requ, cmd);



	rc = ddcb_cmd_fixups(cfile, req);

	if (rc != 0)

		return rc;



	rc = __genwqe_execute_raw_ddcb(cd, cmd);

	rc = __genwqe_execute_raw_ddcb(cd, cmd, filp->f_flags);

	ddcb_cmd_cleanup(cfile, req);

	return rc;

}
@@ -1006,6 +1009,7 @@ static int do_execute_ddcb(struct genwqe_file *cfile, 
	struct genwqe_ddcb_cmd *cmd;

	struct ddcb_requ *req;

	struct genwqe_dev *cd = cfile->cd;

	struct file *filp = cfile->filp;



	cmd = ddcb_requ_alloc();

	if (cmd == NULL)
@@ -1021,7 +1025,7 @@ static int do_execute_ddcb(struct genwqe_file *cfile, 
	if (!raw)

		rc = genwqe_execute_ddcb(cfile, cmd);

	else

		rc = __genwqe_execute_raw_ddcb(cd, cmd);

		rc = __genwqe_execute_raw_ddcb(cd, cmd, filp->f_flags);



	/* Copy back only the modifed fields. Do not copy ASIV

	   back since the copy got modified by the driver. */