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Date: Thu, 11 Apr 2013 14:48:51 +0200
From: Jiri Benc <jbenc@...hat.com>
To: netdev@...r.kernel.org
Cc: Richard Cochran <richardcochran@...il.com>,
Ben Hutchings <bhutchings@...arflare.com>
Subject: [PATCH v2 net-next] ptp: dynamic allocation of PHC char devices
As network adapters supporting PTP are becoming more common, machines with
many NICs suddenly have many PHCs, too. The current limit of eight /dev/ptp*
char devices (and thus, 8 network interfaces with PHC) is insufficient. Let
the ptp driver allocate the char devices dynamically.
idr is used for tracking minor numbers allocation; the mapping from index to
pointer is not used, as it is not needed for posix clocks.
Tested with 28 PHCs, removing and re-adding some of them.
Signed-off-by: Jiri Benc <jbenc@...hat.com>
---
v2: Removed dynamic allocation of chunks of minor numbers, the full minor
range is allocated instead.
---
drivers/ptp/ptp_clock.c | 60 +++++++++++++++++++++++++++++-----------------
1 files changed, 38 insertions(+), 22 deletions(-)
diff --git a/drivers/ptp/ptp_clock.c b/drivers/ptp/ptp_clock.c
index 79f4bce..c8c57bc 100644
--- a/drivers/ptp/ptp_clock.c
+++ b/drivers/ptp/ptp_clock.c
@@ -17,7 +17,7 @@
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
-#include <linux/bitops.h>
+#include <linux/idr.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
@@ -32,7 +32,6 @@
#include "ptp_private.h"
#define PTP_MAX_ALARMS 4
-#define PTP_MAX_CLOCKS 8
#define PTP_PPS_DEFAULTS (PPS_CAPTUREASSERT | PPS_OFFSETASSERT)
#define PTP_PPS_EVENT PPS_CAPTUREASSERT
#define PTP_PPS_MODE (PTP_PPS_DEFAULTS | PPS_CANWAIT | PPS_TSFMT_TSPEC)
@@ -42,7 +41,7 @@
static dev_t ptp_devt;
static struct class *ptp_class;
-static DECLARE_BITMAP(ptp_clocks_map, PTP_MAX_CLOCKS);
+static struct idr ptp_clocks_map;
static DEFINE_MUTEX(ptp_clocks_mutex); /* protects 'ptp_clocks_map' */
/* time stamp event queue operations */
@@ -166,17 +165,36 @@ static struct posix_clock_operations ptp_clock_ops = {
.read = ptp_read,
};
-static void delete_ptp_clock(struct posix_clock *pc)
+static int ptp_clock_alloc_index(struct ptp_clock *ptp)
{
- struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+ int index;
- mutex_destroy(&ptp->tsevq_mux);
+ mutex_lock(&ptp_clocks_mutex);
+ index = idr_alloc(&ptp_clocks_map, ptp, 0, 0, GFP_KERNEL);
+ if (index < 0)
+ goto no_idr;
+ if (index > MINORMASK) {
+ idr_remove(&ptp_clocks_map, index);
+ index = -EBUSY;
+ }
+no_idr:
+ mutex_unlock(&ptp_clocks_mutex);
+ return index;
+}
- /* Remove the clock from the bit map. */
+static void ptp_clock_free_index(int index)
+{
mutex_lock(&ptp_clocks_mutex);
- clear_bit(ptp->index, ptp_clocks_map);
+ idr_remove(&ptp_clocks_map, index);
mutex_unlock(&ptp_clocks_mutex);
+}
+static void delete_ptp_clock(struct posix_clock *pc)
+{
+ struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
+
+ mutex_destroy(&ptp->tsevq_mux);
+ ptp_clock_free_index(ptp->index);
kfree(ptp);
}
@@ -191,21 +209,18 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info,
if (info->n_alarm > PTP_MAX_ALARMS)
return ERR_PTR(-EINVAL);
- /* Find a free clock slot and reserve it. */
- err = -EBUSY;
- mutex_lock(&ptp_clocks_mutex);
- index = find_first_zero_bit(ptp_clocks_map, PTP_MAX_CLOCKS);
- if (index < PTP_MAX_CLOCKS)
- set_bit(index, ptp_clocks_map);
- else
- goto no_slot;
-
/* Initialize a clock structure. */
err = -ENOMEM;
ptp = kzalloc(sizeof(struct ptp_clock), GFP_KERNEL);
if (ptp == NULL)
goto no_memory;
+ index = ptp_clock_alloc_index(ptp);
+ if (index < 0) {
+ err = index;
+ goto no_slot;
+ }
+
ptp->clock.ops = ptp_clock_ops;
ptp->clock.release = delete_ptp_clock;
ptp->info = info;
@@ -260,11 +275,10 @@ no_sysfs:
device_destroy(ptp_class, ptp->devid);
no_device:
mutex_destroy(&ptp->tsevq_mux);
+ ptp_clock_free_index(index);
+no_slot:
kfree(ptp);
no_memory:
- clear_bit(index, ptp_clocks_map);
-no_slot:
- mutex_unlock(&ptp_clocks_mutex);
return ERR_PTR(err);
}
EXPORT_SYMBOL(ptp_clock_register);
@@ -323,7 +337,8 @@ EXPORT_SYMBOL(ptp_clock_index);
static void __exit ptp_exit(void)
{
class_destroy(ptp_class);
- unregister_chrdev_region(ptp_devt, PTP_MAX_CLOCKS);
+ unregister_chrdev_region(ptp_devt, MINORMASK + 1);
+ idr_destroy(&ptp_clocks_map);
}
static int __init ptp_init(void)
@@ -336,7 +351,8 @@ static int __init ptp_init(void)
return PTR_ERR(ptp_class);
}
- err = alloc_chrdev_region(&ptp_devt, 0, PTP_MAX_CLOCKS, "ptp");
+ idr_init(&ptp_clocks_map);
+ err = alloc_chrdev_region(&ptp_devt, 0, MINORMASK + 1, "ptp");
if (err < 0) {
pr_err("ptp: failed to allocate device region\n");
goto no_region;
--
1.7.6.5
--
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