pps: access pps device by direct pointer

Using device index as a pointer needs some unnecessary work to be done
every time the pointer is needed (in irq handler for example).  Using a
direct pointer is much more easy (and safe as well).

Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Acked-by: Rodolfo Giometti <giometti@linux.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 28 insertions, 96 deletions

diff --git a/drivers/pps/kapi.c b/drivers/pps/kapi.c
index b431d83b824a..98d4012ca595 100644
--- a/drivers/pps/kapi.c
+++ b/drivers/pps/kapi.c
@@ -32,11 +32,11 @@
 #include <linux/slab.h>
 
 /*
- * Global variables
+ * Local variables
  */
 
-DEFINE_SPINLOCK(pps_idr_lock);
-DEFINE_IDR(pps_idr);
+static DEFINE_SPINLOCK(pps_idr_lock);
+static DEFINE_IDR(pps_idr);
 
 /*
  * Local functions
@@ -60,60 +60,6 @@ static void pps_add_offset(struct pps_ktime *ts, struct pps_ktime *offset)
  * Exported functions
  */
 
-/* pps_get_source - find a PPS source
- * @source: the PPS source ID.
- *
- * This function is used to find an already registered PPS source into the
- * system.
- *
- * The function returns NULL if found nothing, otherwise it returns a pointer
- * to the PPS source data struct (the refcounter is incremented by 1).
- */
-
-struct pps_device *pps_get_source(int source)
-{
-        struct pps_device *pps;
-        unsigned long flags;
-
-        spin_lock_irqsave(&pps_idr_lock, flags);
-
-        pps = idr_find(&pps_idr, source);
-        if (pps != NULL)
-                atomic_inc(&pps->usage);
-
-        spin_unlock_irqrestore(&pps_idr_lock, flags);
-
-        return pps;
-}
-
-/* pps_put_source - free the PPS source data
- * @pps: a pointer to the PPS source.
- *
- * This function is used to free a PPS data struct if its refcount is 0.
- */
-
-void pps_put_source(struct pps_device *pps)
-{
-        unsigned long flags;
-
-        spin_lock_irqsave(&pps_idr_lock, flags);
-        BUG_ON(atomic_read(&pps->usage) == 0);
-
-        if (!atomic_dec_and_test(&pps->usage)) {
-                pps = NULL;
-                goto exit;
-        }
-
-        /* No more reference to the PPS source. We can safely remove the
-         * PPS data struct.
-         */
-        idr_remove(&pps_idr, pps->id);
-
-exit:
-        spin_unlock_irqrestore(&pps_idr_lock, flags);
-        kfree(pps);
-}
-
 /* pps_register_source - add a PPS source in the system
  * @info: the PPS info struct
  * @default_params: the default PPS parameters of the new source
@@ -122,10 +68,11 @@ exit:
  * source is described by info's fields and it will have, as default PPS
  * parameters, the ones specified into default_params.
  *
- * The function returns, in case of success, the PPS source ID.
+ * The function returns, in case of success, the PPS device. Otherwise NULL.
  */
 
-int pps_register_source(struct pps_source_info *info, int default_params)
+struct pps_device *pps_register_source(struct pps_source_info *info,
+                int default_params)
 {
         struct pps_device *pps;
         int id;
@@ -168,7 +115,6 @@ int pps_register_source(struct pps_source_info *info, int default_params)
 
         init_waitqueue_head(&pps->queue);
         spin_lock_init(&pps->lock);
-        atomic_set(&pps->usage, 1);
 
         /* Get new ID for the new PPS source */
         if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0) {
@@ -211,7 +157,7 @@ int pps_register_source(struct pps_source_info *info, int default_params)
 
         pr_info("new PPS source %s at ID %d\n", info->name, id);
 
-        return id;
+        return pps;
 
 free_idr:
         spin_lock_irq(&pps_idr_lock);
@@ -224,38 +170,33 @@ kfree_pps:
 pps_register_source_exit:
         printk(KERN_ERR "pps: %s: unable to register source\n", info->name);
 
-        return err;
+        return NULL;
 }
 EXPORT_SYMBOL(pps_register_source);
 
 /* pps_unregister_source - remove a PPS source from the system
- * @source: the PPS source ID
+ * @pps: the PPS source
  *
  * This function is used to remove a previously registered PPS source from
  * the system.
  */
 
-void pps_unregister_source(int source)
+void pps_unregister_source(struct pps_device *pps)
 {
-        struct pps_device *pps;
+        unsigned int id = pps->id;
 
-        spin_lock_irq(&pps_idr_lock);
-        pps = idr_find(&pps_idr, source);
+        pps_unregister_cdev(pps);
 
-        if (!pps) {
-                BUG();
-                spin_unlock_irq(&pps_idr_lock);
-                return;
-        }
+        spin_lock_irq(&pps_idr_lock);
+        idr_remove(&pps_idr, pps->id);
         spin_unlock_irq(&pps_idr_lock);
 
-        pps_unregister_cdev(pps);
-        pps_put_source(pps);
+        kfree(pps);
 }
 EXPORT_SYMBOL(pps_unregister_source);
 
 /* pps_event - register a PPS event into the system
- * @source: the PPS source ID
+ * @pps: the PPS device
  * @ts: the event timestamp
  * @event: the event type
  * @data: userdef pointer
@@ -263,30 +204,24 @@ EXPORT_SYMBOL(pps_unregister_source);
  * This function is used by each PPS client in order to register a new
  * PPS event into the system (it's usually called inside an IRQ handler).
  *
- * If an echo function is associated with the PPS source it will be called
+ * If an echo function is associated with the PPS device it will be called
  * as:
- *      pps->info.echo(source, event, data);
+ *      pps->info.echo(pps, event, data);
  */
-
-void pps_event(int source, struct pps_event_time *ts, int event, void *data)
+void pps_event(struct pps_device *pps, struct pps_event_time *ts, int event,
+                void *data)
 {
-        struct pps_device *pps;
         unsigned long flags;
         int captured = 0;
         struct pps_ktime ts_real;
 
         if ((event & (PPS_CAPTUREASSERT | PPS_CAPTURECLEAR)) == 0) {
-                printk(KERN_ERR "pps: unknown event (%x) for source %d\n",
-                        event, source);
+                dev_err(pps->dev, "unknown event (%x)\n", event);
                 return;
         }
 
-        pps = pps_get_source(source);
-        if (!pps)
-                return;
-
-        pr_debug("PPS event on source %d at %ld.%09ld\n",
-                        pps->id, ts->ts_real.tv_sec, ts->ts_real.tv_nsec);
+        dev_dbg(pps->dev, "PPS event at %ld.%09ld\n",
+                        ts->ts_real.tv_sec, ts->ts_real.tv_nsec);
 
         timespec_to_pps_ktime(&ts_real, ts->ts_real);
 
@@ -294,7 +229,7 @@ void pps_event(int source, struct pps_event_time *ts, int event, void *data)
 
         /* Must call the echo function? */
         if ((pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)))
-                pps->info.echo(source, event, data);
+                pps->info.echo(pps, event, data);
 
         /* Check the event */
         pps->current_mode = pps->params.mode;
@@ -308,8 +243,8 @@ void pps_event(int source, struct pps_event_time *ts, int event, void *data)
                 /* Save the time stamp */
                 pps->assert_tu = ts_real;
                 pps->assert_sequence++;
-                pr_debug("capture assert seq #%u for source %d\n",
-                        pps->assert_sequence, source);
+                dev_dbg(pps->dev, "capture assert seq #%u\n",
+                        pps->assert_sequence);
 
                 captured = ~0;
         }
@@ -323,8 +258,8 @@ void pps_event(int source, struct pps_event_time *ts, int event, void *data)
                 /* Save the time stamp */
                 pps->clear_tu = ts_real;
                 pps->clear_sequence++;
-                pr_debug("capture clear seq #%u for source %d\n",
-                        pps->clear_sequence, source);
+                dev_dbg(pps->dev, "capture clear seq #%u\n",
+                        pps->clear_sequence);
 
                 captured = ~0;
         }
@@ -338,8 +273,5 @@ void pps_event(int source, struct pps_event_time *ts, int event, void *data)
         }
 
         spin_unlock_irqrestore(&pps->lock, flags);
-
-        /* Now we can release the PPS source for (possible) deregistration */
-        pps_put_source(pps);
 }
 EXPORT_SYMBOL(pps_event);