From: Frank Haverkamp <haver@linux.vnet.ibm.com>
Date: Wed, 10 Sep 2014 14:37:53 +0000 (+0200)
Subject: GenWQE: Support blocking when DDCB queue is busy
X-Git-Tag: firefly_0821_release~176^2~3117^2~31
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1451f414639465995dfc1f820aa1a64723cbd662;p=firefly-linux-kernel-4.4.55.git
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>
---
diff --git a/drivers/misc/genwqe/card_base.h b/drivers/misc/genwqe/card_base.h
index b622d204b72b..c64d7cad1085 100644
--- a/drivers/misc/genwqe/card_base.h
+++ b/drivers/misc/genwqe/card_base.h
@@ -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);
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;
diff --git a/drivers/misc/genwqe/card_debugfs.c b/drivers/misc/genwqe/card_debugfs.c
index 40b425d35866..c715534e7fe7 100644
--- a/drivers/misc/genwqe/card_debugfs.c
+++ b/drivers/misc/genwqe/card_debugfs.c
@@ -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"
diff --git a/drivers/misc/genwqe/card_dev.c b/drivers/misc/genwqe/card_dev.c
index 59e0081acc8f..5918586f2f76 100644
--- a/drivers/misc/genwqe/card_dev.c
+++ b/drivers/misc/genwqe/card_dev.c
@@ -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. */