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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: Jiri Benc <jbenc@redhat.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jiri Benc 2013-04-12 00:56:15 +00:00 committed by David S. Miller
parent d6a4a10411
commit 7356a764cd
1 changed files with 13 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
drivers/ptp/ptp_clock.c
View File

@ -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;