linux-kernel - [patch 13/13] ptp: Convert ptp_open/read() to _

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Message-ID: <20250620131944.533741574@linutronix.de>
Date: Fri, 20 Jun 2025 15:24:50 +0200 (CEST)
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Richard Cochran <richardcochran@...il.com>,
 netdev@...r.kernel.org
Subject: [patch 13/13] ptp: Convert ptp_open/read() to __free()

Get rid of the kfree() and goto maze and just return error codes directly.

No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 drivers/ptp/ptp_chardev.c |   70 ++++++++++++----------------------------------
 1 file changed, 19 insertions(+), 51 deletions(-)

--- a/drivers/ptp/ptp_chardev.c
+++ b/drivers/ptp/ptp_chardev.c
@@ -106,19 +106,17 @@ int ptp_set_pinfunc(struct ptp_clock *pt
 
 int ptp_open(struct posix_clock_context *pccontext, fmode_t fmode)
 {
-	struct ptp_clock *ptp =
-		container_of(pccontext->clk, struct ptp_clock, clock);
-	struct timestamp_event_queue *queue;
+	struct ptp_clock *ptp =	container_of(pccontext->clk, struct ptp_clock, clock);
+	struct timestamp_event_queue *queue __free(kfree) = NULL;
 	char debugfsname[32];
 
 	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
 	if (!queue)
 		return -EINVAL;
 	queue->mask = bitmap_alloc(PTP_MAX_CHANNELS, GFP_KERNEL);
-	if (!queue->mask) {
-		kfree(queue);
+	if (!queue->mask)
 		return -EINVAL;
-	}
+
 	bitmap_set(queue->mask, 0, PTP_MAX_CHANNELS);
 	spin_lock_init(&queue->lock);
 	scoped_guard(spinlock_irq, &ptp->tsevqs_lock)
@@ -134,7 +132,6 @@ int ptp_open(struct posix_clock_context
 		DIV_ROUND_UP(PTP_MAX_CHANNELS, BITS_PER_BYTE * sizeof(u32));
 	debugfs_create_u32_array("mask", 0444, queue->debugfs_instance,
 				 &queue->dfs_bitmap);
-
 	return 0;
 }
 
@@ -540,67 +537,38 @@ long ptp_ioctl(struct posix_clock_contex
 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 timestamp_event_queue *queue;
-	struct ptp_extts_event *event;
-	int result;
+	struct ptp_clock *ptp =	container_of(pccontext->clk, struct ptp_clock, clock);
+	struct timestamp_event_queue *queue = pccontext->private_clkdata;
+	struct ptp_extts_event *event __free(kfree) = NULL;
 
-	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(struct ptp_extts_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 = cnt * sizeof(struct ptp_extts_event);
-
-	result = cnt;
-	if (copy_to_user(buf, event, cnt)) {
-		result = -EFAULT;
-		goto free_event;
-	}
-
-free_event:
-	kfree(event);
-exit:
-	return result;
+	return copy_to_user(buf, event, cnt) ? -EFAULT : cnt;
 }