@@ -21,6 +21,7 @@
#include <linux/posix-clock.h>
#include <linux/poll.h>
#include <linux/sched.h>
+#include <linux/slab.h>
#include "ptp_private.h"
@@ -136,20 +137,23 @@ unsigned int ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
return queue_cnt(&ptp->tsevq) ? POLLIN : 0;
}
+#define EXTTS_BUFSIZE (PTP_BUF_TIMESTAMPS * sizeof(struct ptp_extts_event))
+
ssize_t ptp_read(struct posix_clock *pc,
uint rdflags, char __user *buf, size_t cnt)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
struct timestamp_event_queue *queue = &ptp->tsevq;
- struct ptp_extts_event event[PTP_BUF_TIMESTAMPS];
+ struct ptp_extts_event *event;
unsigned long flags;
size_t qcnt, i;
+ int result;
if (cnt % sizeof(struct ptp_extts_event) != 0)
return -EINVAL;
- if (cnt > sizeof(event))
- cnt = sizeof(event);
+ if (cnt > EXTTS_BUFSIZE)
+ cnt = EXTTS_BUFSIZE;
cnt = cnt / sizeof(struct ptp_extts_event);
@@ -167,6 +171,12 @@ ssize_t ptp_read(struct posix_clock *pc,
return -ENODEV;
}
+ event = kmalloc(EXTTS_BUFSIZE, GFP_KERNEL);
+ if (!event) {
+ mutex_unlock(&ptp->tsevq_mux);
+ return -ENOMEM;
+ }
+
spin_lock_irqsave(&queue->lock, flags);
qcnt = queue_cnt(queue);
@@ -185,8 +195,10 @@ ssize_t ptp_read(struct posix_clock *pc,
mutex_unlock(&ptp->tsevq_mux);
+ result = cnt;
if (copy_to_user(buf, event, cnt))
- return -EFAULT;
+ result = -EFAULT;
- return cnt;
+ kfree(event);
+ return result;
}
This patch removes the large buffer from the stack of the read file operation and replaces it with a kmalloced buffer. Signed-off-by: Richard Cochran <richardcochran@gmail.com> --- drivers/ptp/ptp_chardev.c | 22 +++++++++++++++++----- 1 files changed, 17 insertions(+), 5 deletions(-)