// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Copyright (c) 2014 David Jander, Protonic Holland
- * Copyright (C) 2014-2017 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>
+/* Copyright (c) 2014 Protonic Holland,
+ * David Jander
+ * Copyright (C) 2014-2017 Pengutronix,
+ * Marc Kleine-Budde <kernel@pengutronix.de>
*/
#include <linux/can/dev.h>
u32 timestamp;
};
-static inline struct can_rx_offload_cb *can_rx_offload_get_cb(struct sk_buff *skb)
+static inline struct can_rx_offload_cb *
+can_rx_offload_get_cb(struct sk_buff *skb)
{
BUILD_BUG_ON(sizeof(struct can_rx_offload_cb) > sizeof(skb->cb));
return (struct can_rx_offload_cb *)skb->cb;
}
-static inline bool can_rx_offload_le(struct can_rx_offload *offload, unsigned int a, unsigned int b)
+static inline bool
+can_rx_offload_le(struct can_rx_offload *offload,
+ unsigned int a, unsigned int b)
{
if (offload->inc)
return a <= b;
return a >= b;
}
-static inline unsigned int can_rx_offload_inc(struct can_rx_offload *offload, unsigned int *val)
+static inline unsigned int
+can_rx_offload_inc(struct can_rx_offload *offload, unsigned int *val)
{
if (offload->inc)
return (*val)++;
static int can_rx_offload_napi_poll(struct napi_struct *napi, int quota)
{
- struct can_rx_offload *offload = container_of(napi, struct can_rx_offload, napi);
+ struct can_rx_offload *offload = container_of(napi,
+ struct can_rx_offload,
+ napi);
struct net_device *dev = offload->dev;
struct net_device_stats *stats = &dev->stats;
struct sk_buff *skb;
return work_done;
}
-static inline void __skb_queue_add_sort(struct sk_buff_head *head, struct sk_buff *new,
- int (*compare)(struct sk_buff *a, struct sk_buff *b))
+static inline void
+__skb_queue_add_sort(struct sk_buff_head *head, struct sk_buff *new,
+ int (*compare)(struct sk_buff *a, struct sk_buff *b))
{
struct sk_buff *pos, *insert = NULL;
return cb_b->timestamp - cb_a->timestamp;
}
-static struct sk_buff *can_rx_offload_offload_one(struct can_rx_offload *offload, unsigned int n)
+/**
+ * can_rx_offload_offload_one() - Read one CAN frame from HW
+ * @offload: pointer to rx_offload context
+ * @n: number of mailbox to read
+ *
+ * The task of this function is to read a CAN frame from mailbox @n
+ * from the device and return the mailbox's content as a struct
+ * sk_buff.
+ *
+ * If the struct can_rx_offload::skb_queue exceeds the maximal queue
+ * length (struct can_rx_offload::skb_queue_len_max) or no skb can be
+ * allocated, the mailbox contents is discarded by reading it into an
+ * overflow buffer. This way the mailbox is marked as free by the
+ * driver.
+ *
+ * Return: A pointer to skb containing the CAN frame on success.
+ *
+ * NULL if the mailbox @n is empty.
+ *
+ * ERR_PTR() in case of an error
+ */
+static struct sk_buff *
+can_rx_offload_offload_one(struct can_rx_offload *offload, unsigned int n)
{
- struct sk_buff *skb = NULL;
+ struct sk_buff *skb = NULL, *skb_error = NULL;
struct can_rx_offload_cb *cb;
struct can_frame *cf;
int ret;
- /* If queue is full or skb not available, read to discard mailbox */
- if (likely(skb_queue_len(&offload->skb_queue) <=
- offload->skb_queue_len_max))
+ if (likely(skb_queue_len(&offload->skb_queue) <
+ offload->skb_queue_len_max)) {
skb = alloc_can_skb(offload->dev, &cf);
+ if (unlikely(!skb))
+ skb_error = ERR_PTR(-ENOMEM); /* skb alloc failed */
+ } else {
+ skb_error = ERR_PTR(-ENOBUFS); /* skb_queue is full */
+ }
- if (!skb) {
+ /* If queue is full or skb not available, drop by reading into
+ * overflow buffer.
+ */
+ if (unlikely(skb_error)) {
struct can_frame cf_overflow;
u32 timestamp;
ret = offload->mailbox_read(offload, &cf_overflow,
×tamp, n);
- if (ret)
- offload->dev->stats.rx_dropped++;
- return NULL;
+ /* Mailbox was empty. */
+ if (unlikely(!ret))
+ return NULL;
+
+ /* Mailbox has been read and we're dropping it or
+ * there was a problem reading the mailbox.
+ *
+ * Increment error counters in any case.
+ */
+ offload->dev->stats.rx_dropped++;
+ offload->dev->stats.rx_fifo_errors++;
+
+ /* There was a problem reading the mailbox, propagate
+ * error value.
+ */
+ if (unlikely(ret < 0))
+ return ERR_PTR(ret);
+
+ return skb_error;
}
cb = can_rx_offload_get_cb(skb);
ret = offload->mailbox_read(offload, cf, &cb->timestamp, n);
- if (!ret) {
+
+ /* Mailbox was empty. */
+ if (unlikely(!ret)) {
kfree_skb(skb);
return NULL;
}
+ /* There was a problem reading the mailbox, propagate error value. */
+ if (unlikely(ret < 0)) {
+ kfree_skb(skb);
+
+ offload->dev->stats.rx_dropped++;
+ offload->dev->stats.rx_fifo_errors++;
+
+ return ERR_PTR(ret);
+ }
+
+ /* Mailbox was read. */
return skb;
}
-int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload, u64 pending)
+int can_rx_offload_irq_offload_timestamp(struct can_rx_offload *offload,
+ u64 pending)
{
struct sk_buff_head skb_queue;
unsigned int i;
continue;
skb = can_rx_offload_offload_one(offload, i);
- if (!skb)
- break;
+ if (IS_ERR_OR_NULL(skb))
+ continue;
__skb_queue_add_sort(&skb_queue, skb, can_rx_offload_compare);
}
struct sk_buff *skb;
int received = 0;
- while ((skb = can_rx_offload_offload_one(offload, 0))) {
+ while (1) {
+ skb = can_rx_offload_offload_one(offload, 0);
+ if (IS_ERR(skb))
+ continue;
+ if (!skb)
+ break;
+
skb_queue_tail(&offload->skb_queue, skb);
received++;
}
unsigned long flags;
if (skb_queue_len(&offload->skb_queue) >
- offload->skb_queue_len_max)
- return -ENOMEM;
+ offload->skb_queue_len_max) {
+ kfree_skb(skb);
+ return -ENOBUFS;
+ }
cb = can_rx_offload_get_cb(skb);
cb->timestamp = timestamp;
struct sk_buff *skb)
{
if (skb_queue_len(&offload->skb_queue) >
- offload->skb_queue_len_max)
- return -ENOMEM;
+ offload->skb_queue_len_max) {
+ kfree_skb(skb);
+ return -ENOBUFS;
+ }
skb_queue_tail(&offload->skb_queue, skb);
can_rx_offload_schedule(offload);
}
EXPORT_SYMBOL_GPL(can_rx_offload_queue_tail);
-static int can_rx_offload_init_queue(struct net_device *dev, struct can_rx_offload *offload, unsigned int weight)
+static int can_rx_offload_init_queue(struct net_device *dev,
+ struct can_rx_offload *offload,
+ unsigned int weight)
{
offload->dev = dev;
return 0;
}
-int can_rx_offload_add_timestamp(struct net_device *dev, struct can_rx_offload *offload)
+int can_rx_offload_add_timestamp(struct net_device *dev,
+ struct can_rx_offload *offload)
{
unsigned int weight;
}
EXPORT_SYMBOL_GPL(can_rx_offload_add_timestamp);
-int can_rx_offload_add_fifo(struct net_device *dev, struct can_rx_offload *offload, unsigned int weight)
+int can_rx_offload_add_fifo(struct net_device *dev,
+ struct can_rx_offload *offload, unsigned int weight)
{
if (!offload->mailbox_read)
return -EINVAL;
projects / linux-2.6-microblaze.git / blobdiff