ptp: Simplify ptp_read()

The mixture of gotos and direct return codes is inconsistent and just makes
the code harder to read. Let it consistently return error codes directly and
tidy the code flow up accordingly.

No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://patch.msgid.link/20250625115133.486953538@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/ptp/ptp_chardev.c b/drivers/ptp/ptp_chardev.c
index 8ccc2ad32a811eb5c355b5dd44915521e054e915..6b611fe5a95ea37b25391770109c43f8909bbf7c 100644 (file)
--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -106,8 +106,7 @@ int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin,
 
 int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode)
 {
-       struct ptp_clock *ptp =
-               container_of(pccontext->clk, struct ptp_clock, clock);
+       struct ptp_clock *ptp = container_of(pccontext->clk, struct ptp_clock, clock);
        struct timestamp_event_queue *queue;
        char debugfsname[32];
 
@@ -536,67 +535,46 @@ __poll_t ptp_poll(struct posix_clock_context *pccontext, struct file *fp,
 ssize_t ptp_read(struct posix_clock_context *pccontext, uint rdflags,
                 char __user *buf, size_t cnt)
 {
-       struct ptp_clock *ptp =
-               container_of(pccontext->clk, struct ptp_clock, clock);
+       struct ptp_clock *ptp = container_of(pccontext->clk, struct ptp_clock, clock);
        struct timestamp_event_queue *queue;
        struct ptp_extts_event *event;
-       int result;
+       ssize_t result;
 
        queue = pccontext->private_clkdata;
-       if (!queue) {
-               result = -EINVAL;
-               goto exit;
-       }
+       if (!queue)
+               return -EINVAL;
 
-       if (cnt % sizeof(struct ptp_extts_event) != 0) {
-               result = -EINVAL;
-               goto exit;
-       }
+       if (cnt % sizeof(*event) != 0)
+               return -EINVAL;
 
        if (cnt > EXTTS_BUFSIZE)
                cnt = EXTTS_BUFSIZE;
 
-       cnt = cnt / sizeof(struct ptp_extts_event);
-
-       if (wait_event_interruptible(ptp->tsev_wq,
-                                    ptp->defunct || queue_cnt(queue))) {
+       if (wait_event_interruptible(ptp->tsev_wq, ptp->defunct || queue_cnt(queue)))
                return -ERESTARTSYS;
-       }
 
-       if (ptp->defunct) {
-               result = -ENODEV;
-               goto exit;
-       }
+       if (ptp->defunct)
+               return -ENODEV;
 
        event = kmalloc(EXTTS_BUFSIZE, GFP_KERNEL);
-       if (!event) {
-               result = -ENOMEM;
-               goto exit;
-       }
+       if (!event)
+               return -ENOMEM;
 
        scoped_guard(spinlock_irq, &queue->lock) {
-               size_t qcnt = queue_cnt(queue);
-
-               if (cnt > qcnt)
-                       cnt = qcnt;
+               size_t qcnt = min((size_t)queue_cnt(queue), cnt / sizeof(*event));
 
-               for (size_t i = 0; i < cnt; i++) {
+               for (size_t i = 0; i < qcnt; i++) {
                        event[i] = queue->buf[queue->head];
                        /* Paired with READ_ONCE() in queue_cnt() */
                        WRITE_ONCE(queue->head, (queue->head + 1) % PTP_MAX_TIMESTAMPS);
                }
+               cnt = qcnt * sizeof(*event);
        }
 
-       cnt = cnt * sizeof(struct ptp_extts_event);
-
        result = cnt;
-       if (copy_to_user(buf, event, cnt)) {
+       if (copy_to_user(buf, event, cnt))
                result = -EFAULT;
-               goto free_event;
-       }
 
-free_event:
        kfree(event);
-exit:
        return result;
 }