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Commit 7356a764 authored by Jiri Benc's avatar Jiri Benc Committed by David S. Miller
Browse files

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.

Tested with 28 PHCs, removing and re-adding some of them.

Thanks to Ben Hutchings for advice leading to simpler and cleaner patch.

Signed-off-by: default avatarJiri Benc <jbenc@redhat.com>
Acked-by: default avatarRichard Cochran <richardcochran@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d6a4a104

drivers/ptp/ptp_clock.c

+13 −25
Original line number Diff line number Diff line
@@ -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)
@@ -42,8 +41,7 @@ 
static dev_t ptp_devt;

static struct class *ptp_class;



static DECLARE_BITMAP(ptp_clocks_map, PTP_MAX_CLOCKS);

static DEFINE_MUTEX(ptp_clocks_mutex); /* protects 'ptp_clocks_map' */

static DEFINE_IDA(ptp_clocks_map);



/* time stamp event queue operations */
@@ -171,12 +169,7 @@ 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);



	/* Remove the clock from the bit map. */

	mutex_lock(&ptp_clocks_mutex);

	clear_bit(ptp->index, ptp_clocks_map);

	mutex_unlock(&ptp_clocks_mutex);



	ida_simple_remove(&ptp_clocks_map, ptp->index);

	kfree(ptp);

}
@@ -191,21 +184,18 @@ 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 = ida_simple_get(&ptp_clocks_map, 0, MINORMASK + 1, GFP_KERNEL);

	if (index < 0) {

		err = index;

		goto no_slot;

	}



	ptp->clock.ops = ptp_clock_ops;

	ptp->clock.release = delete_ptp_clock;

	ptp->info = info;
@@ -248,7 +238,6 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info, 
		goto no_clock;

	}



	mutex_unlock(&ptp_clocks_mutex);

	return ptp;



no_clock:
@@ -260,11 +249,9 @@ struct ptp_clock *ptp_clock_register(struct ptp_clock_info *info, 
	device_destroy(ptp_class, ptp->devid);

no_device:

	mutex_destroy(&ptp->tsevq_mux);

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 +310,8 @@ 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);

	ida_destroy(&ptp_clocks_map);

}



static int __init ptp_init(void)
@@ -336,7 +324,7 @@ static int __init ptp_init(void) 
		return PTR_ERR(ptp_class);

	}



	err = alloc_chrdev_region(&ptp_devt, 0, PTP_MAX_CLOCKS, "ptp");

	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;