usb: gadget: u_serial: Use kfifo instead of homemade circular buffer
The kernel FIFO implementation, kfifo, provides interfaces to manipulate a first-in-first-out circular buffer. Use kfifo instead of the homemade one to make the code more concise and readable. Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Lu Baolu
Felipe Balbi
Родитель
204ec1af62
Коммит
a622ee9972
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@ -26,6 +26,7 @@
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#include <linux/module.h>
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#include <linux/console.h>
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#include <linux/kthread.h>
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#include <linux/kfifo.h>
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#include "u_serial.h"
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@ -80,19 +81,11 @@
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#define WRITE_BUF_SIZE 8192 /* TX only */
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#define GS_CONSOLE_BUF_SIZE 8192
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/* circular buffer */
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struct gs_buf {
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unsigned buf_size;
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char *buf_buf;
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char *buf_get;
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char *buf_put;
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};
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/* console info */
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struct gscons_info {
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struct gs_port *port;
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struct task_struct *console_thread;
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struct gs_buf con_buf;
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struct kfifo con_buf;
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/* protect the buf and busy flag */
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spinlock_t con_lock;
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int req_busy;
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@ -122,7 +115,7 @@ struct gs_port {
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struct list_head write_pool;
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int write_started;
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int write_allocated;
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struct gs_buf port_write_buf;
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struct kfifo port_write_buf;
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wait_queue_head_t drain_wait; /* wait while writes drain */
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bool write_busy;
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wait_queue_head_t close_wait;
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@ -154,144 +147,6 @@ static struct portmaster {
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/*-------------------------------------------------------------------------*/
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/* Circular Buffer */
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/*
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* gs_buf_alloc
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*
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* Allocate a circular buffer and all associated memory.
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*/
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static int gs_buf_alloc(struct gs_buf *gb, unsigned size)
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{
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gb->buf_buf = kmalloc(size, GFP_KERNEL);
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if (gb->buf_buf == NULL)
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return -ENOMEM;
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gb->buf_size = size;
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gb->buf_put = gb->buf_buf;
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gb->buf_get = gb->buf_buf;
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return 0;
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}
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/*
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* gs_buf_free
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*
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* Free the buffer and all associated memory.
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*/
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static void gs_buf_free(struct gs_buf *gb)
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{
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kfree(gb->buf_buf);
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gb->buf_buf = NULL;
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}
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/*
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* gs_buf_clear
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*
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* Clear out all data in the circular buffer.
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*/
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static void gs_buf_clear(struct gs_buf *gb)
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{
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gb->buf_get = gb->buf_put;
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/* equivalent to a get of all data available */
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}
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/*
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* gs_buf_data_avail
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*
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* Return the number of bytes of data written into the circular
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* buffer.
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*/
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static unsigned gs_buf_data_avail(struct gs_buf *gb)
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{
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return (gb->buf_size + gb->buf_put - gb->buf_get) % gb->buf_size;
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}
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/*
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* gs_buf_space_avail
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*
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* Return the number of bytes of space available in the circular
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* buffer.
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*/
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static unsigned gs_buf_space_avail(struct gs_buf *gb)
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{
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return (gb->buf_size + gb->buf_get - gb->buf_put - 1) % gb->buf_size;
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}
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/*
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* gs_buf_put
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*
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* Copy data data from a user buffer and put it into the circular buffer.
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* Restrict to the amount of space available.
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*
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* Return the number of bytes copied.
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*/
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static unsigned
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gs_buf_put(struct gs_buf *gb, const char *buf, unsigned count)
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{
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unsigned len;
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len = gs_buf_space_avail(gb);
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if (count > len)
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count = len;
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if (count == 0)
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return 0;
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len = gb->buf_buf + gb->buf_size - gb->buf_put;
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if (count > len) {
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memcpy(gb->buf_put, buf, len);
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memcpy(gb->buf_buf, buf+len, count - len);
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gb->buf_put = gb->buf_buf + count - len;
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} else {
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memcpy(gb->buf_put, buf, count);
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if (count < len)
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gb->buf_put += count;
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else /* count == len */
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gb->buf_put = gb->buf_buf;
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}
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return count;
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}
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/*
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* gs_buf_get
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*
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* Get data from the circular buffer and copy to the given buffer.
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* Restrict to the amount of data available.
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*
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* Return the number of bytes copied.
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*/
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static unsigned
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gs_buf_get(struct gs_buf *gb, char *buf, unsigned count)
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{
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unsigned len;
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len = gs_buf_data_avail(gb);
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if (count > len)
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count = len;
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if (count == 0)
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return 0;
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len = gb->buf_buf + gb->buf_size - gb->buf_get;
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if (count > len) {
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memcpy(buf, gb->buf_get, len);
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memcpy(buf+len, gb->buf_buf, count - len);
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gb->buf_get = gb->buf_buf + count - len;
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} else {
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memcpy(buf, gb->buf_get, count);
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if (count < len)
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gb->buf_get += count;
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else /* count == len */
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gb->buf_get = gb->buf_buf;
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}
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return count;
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}
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/*-------------------------------------------------------------------------*/
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/* I/O glue between TTY (upper) and USB function (lower) driver layers */
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/*
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@ -346,11 +201,11 @@ gs_send_packet(struct gs_port *port, char *packet, unsigned size)
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{
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unsigned len;
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len = gs_buf_data_avail(&port->port_write_buf);
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len = kfifo_len(&port->port_write_buf);
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if (len < size)
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size = len;
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if (size != 0)
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size = gs_buf_get(&port->port_write_buf, packet, size);
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size = kfifo_out(&port->port_write_buf, packet, size);
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return size;
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}
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@ -398,7 +253,7 @@ __acquires(&port->port_lock)
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req->length = len;
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list_del(&req->list);
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req->zero = (gs_buf_data_avail(&port->port_write_buf) == 0);
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req->zero = kfifo_is_empty(&port->port_write_buf);
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pr_vdebug("ttyGS%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n",
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port->port_num, len, *((u8 *)req->buf),
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@ -787,10 +642,11 @@ static int gs_open(struct tty_struct *tty, struct file *file)
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spin_lock_irq(&port->port_lock);
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/* allocate circular buffer on first open */
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if (port->port_write_buf.buf_buf == NULL) {
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if (!kfifo_initialized(&port->port_write_buf)) {
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spin_unlock_irq(&port->port_lock);
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status = gs_buf_alloc(&port->port_write_buf, WRITE_BUF_SIZE);
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status = kfifo_alloc(&port->port_write_buf,
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WRITE_BUF_SIZE, GFP_KERNEL);
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spin_lock_irq(&port->port_lock);
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if (status) {
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@ -839,7 +695,7 @@ static int gs_writes_finished(struct gs_port *p)
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/* return true on disconnect or empty buffer */
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spin_lock_irq(&p->port_lock);
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cond = (p->port_usb == NULL) || !gs_buf_data_avail(&p->port_write_buf);
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cond = (p->port_usb == NULL) || !kfifo_len(&p->port_write_buf);
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spin_unlock_irq(&p->port_lock);
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return cond;
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@ -875,7 +731,7 @@ static void gs_close(struct tty_struct *tty, struct file *file)
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/* wait for circular write buffer to drain, disconnect, or at
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* most GS_CLOSE_TIMEOUT seconds; then discard the rest
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*/
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if (gs_buf_data_avail(&port->port_write_buf) > 0 && gser) {
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if (kfifo_len(&port->port_write_buf) > 0 && gser) {
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spin_unlock_irq(&port->port_lock);
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wait_event_interruptible_timeout(port->drain_wait,
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gs_writes_finished(port),
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@ -889,9 +745,9 @@ static void gs_close(struct tty_struct *tty, struct file *file)
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* let the push tasklet fire again until we're re-opened.
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*/
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if (gser == NULL)
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gs_buf_free(&port->port_write_buf);
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kfifo_free(&port->port_write_buf);
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else
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gs_buf_clear(&port->port_write_buf);
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kfifo_reset(&port->port_write_buf);
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port->port.tty = NULL;
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@ -915,7 +771,7 @@ static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count)
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spin_lock_irqsave(&port->port_lock, flags);
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if (count)
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count = gs_buf_put(&port->port_write_buf, buf, count);
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count = kfifo_in(&port->port_write_buf, buf, count);
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/* treat count == 0 as flush_chars() */
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if (port->port_usb)
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gs_start_tx(port);
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@ -934,7 +790,7 @@ static int gs_put_char(struct tty_struct *tty, unsigned char ch)
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port->port_num, tty, ch, __builtin_return_address(0));
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spin_lock_irqsave(&port->port_lock, flags);
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status = gs_buf_put(&port->port_write_buf, &ch, 1);
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status = kfifo_put(&port->port_write_buf, ch);
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spin_unlock_irqrestore(&port->port_lock, flags);
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return status;
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@ -961,7 +817,7 @@ static int gs_write_room(struct tty_struct *tty)
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spin_lock_irqsave(&port->port_lock, flags);
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if (port->port_usb)
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room = gs_buf_space_avail(&port->port_write_buf);
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room = kfifo_avail(&port->port_write_buf);
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spin_unlock_irqrestore(&port->port_lock, flags);
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pr_vdebug("gs_write_room: (%d,%p) room=%d\n",
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@ -977,7 +833,7 @@ static int gs_chars_in_buffer(struct tty_struct *tty)
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int chars = 0;
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spin_lock_irqsave(&port->port_lock, flags);
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chars = gs_buf_data_avail(&port->port_write_buf);
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chars = kfifo_len(&port->port_write_buf);
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spin_unlock_irqrestore(&port->port_lock, flags);
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pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n",
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@ -1148,7 +1004,7 @@ static int gs_console_thread(void *data)
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ep = port->port_usb->in;
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spin_lock_irq(&info->con_lock);
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count = gs_buf_data_avail(&info->con_buf);
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count = kfifo_len(&info->con_buf);
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size = ep->maxpacket;
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if (count > 0 && !info->req_busy) {
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@ -1156,7 +1012,7 @@ static int gs_console_thread(void *data)
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if (count < size)
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size = count;
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xfer = gs_buf_get(&info->con_buf, req->buf, size);
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xfer = kfifo_out(&info->con_buf, req->buf, size);
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req->length = xfer;
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spin_unlock(&info->con_lock);
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@ -1192,7 +1048,7 @@ static int gs_console_setup(struct console *co, char *options)
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info->req_busy = 0;
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spin_lock_init(&info->con_lock);
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status = gs_buf_alloc(&info->con_buf, GS_CONSOLE_BUF_SIZE);
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status = kfifo_alloc(&info->con_buf, GS_CONSOLE_BUF_SIZE, GFP_KERNEL);
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if (status) {
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pr_err("%s: allocate console buffer failed\n", __func__);
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return status;
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@ -1202,7 +1058,7 @@ static int gs_console_setup(struct console *co, char *options)
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co, "gs_console");
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if (IS_ERR(info->console_thread)) {
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pr_err("%s: cannot create console thread\n", __func__);
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gs_buf_free(&info->con_buf);
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kfifo_free(&info->con_buf);
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return PTR_ERR(info->console_thread);
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}
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wake_up_process(info->console_thread);
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@ -1217,7 +1073,7 @@ static void gs_console_write(struct console *co,
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unsigned long flags;
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spin_lock_irqsave(&info->con_lock, flags);
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gs_buf_put(&info->con_buf, buf, count);
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kfifo_in(&info->con_buf, buf, count);
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spin_unlock_irqrestore(&info->con_lock, flags);
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wake_up_process(info->console_thread);
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@ -1256,7 +1112,7 @@ static void gserial_console_exit(void)
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unregister_console(&gserial_cons);
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if (!IS_ERR_OR_NULL(info->console_thread))
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kthread_stop(info->console_thread);
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gs_buf_free(&info->con_buf);
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kfifo_free(&info->con_buf);
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}
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#else
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@ -1529,7 +1385,7 @@ void gserial_disconnect(struct gserial *gser)
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/* finally, free any unused/unusable I/O buffers */
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spin_lock_irqsave(&port->port_lock, flags);
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if (port->port.count == 0 && !port->openclose)
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gs_buf_free(&port->port_write_buf);
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kfifo_free(&port->port_write_buf);
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gs_free_requests(gser->out, &port->read_pool, NULL);
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gs_free_requests(gser->out, &port->read_queue, NULL);
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gs_free_requests(gser->in, &port->write_pool, NULL);
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