Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c
index b481002..9453147 100644
--- a/drivers/hid/hid-debug.c
+++ b/drivers/hid/hid-debug.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* (c) 1999 Andreas Gal <gal@cs.uni-magdeburg.de>
* (c) 2000-2001 Vojtech Pavlik <vojtech@ucw.cz>
@@ -7,19 +8,6 @@
*/
/*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Should you need to contact me, the author, you can do so either by
* e-mail - mail your message to <vojtech@ucw.cz>, or by paper mail:
@@ -30,6 +18,7 @@
#include <linux/debugfs.h>
#include <linux/seq_file.h>
+#include <linux/kfifo.h>
#include <linux/sched/signal.h>
#include <linux/export.h>
#include <linux/slab.h>
@@ -661,17 +650,12 @@
/* enqueue string to 'events' ring buffer */
void hid_debug_event(struct hid_device *hdev, char *buf)
{
- unsigned i;
struct hid_debug_list *list;
unsigned long flags;
spin_lock_irqsave(&hdev->debug_list_lock, flags);
- list_for_each_entry(list, &hdev->debug_list, node) {
- for (i = 0; buf[i]; i++)
- list->hid_debug_buf[(list->tail + i) % HID_DEBUG_BUFSIZE] =
- buf[i];
- list->tail = (list->tail + i) % HID_DEBUG_BUFSIZE;
- }
+ list_for_each_entry(list, &hdev->debug_list, node)
+ kfifo_in(&list->hid_debug_fifo, buf, strlen(buf));
spin_unlock_irqrestore(&hdev->debug_list_lock, flags);
wake_up_interruptible(&hdev->debug_wait);
@@ -722,8 +706,7 @@
hid_debug_event(hdev, buf);
kfree(buf);
- wake_up_interruptible(&hdev->debug_wait);
-
+ wake_up_interruptible(&hdev->debug_wait);
}
EXPORT_SYMBOL_GPL(hid_dump_input);
@@ -1065,16 +1048,16 @@
seq_printf(f, "\n\n");
/* dump parsed data and input mappings */
+ if (down_interruptible(&hdev->driver_input_lock))
+ return 0;
+
hid_dump_device(hdev, f);
seq_printf(f, "\n");
hid_dump_input_mapping(hdev, f);
- return 0;
-}
+ up(&hdev->driver_input_lock);
-static int hid_debug_rdesc_open(struct inode *inode, struct file *file)
-{
- return single_open(file, hid_debug_rdesc_show, inode->i_private);
+ return 0;
}
static int hid_debug_events_open(struct inode *inode, struct file *file)
@@ -1088,8 +1071,8 @@
goto out;
}
- if (!(list->hid_debug_buf = kzalloc(HID_DEBUG_BUFSIZE, GFP_KERNEL))) {
- err = -ENOMEM;
+ err = kfifo_alloc(&list->hid_debug_fifo, HID_DEBUG_FIFOSIZE, GFP_KERNEL);
+ if (err) {
kfree(list);
goto out;
}
@@ -1109,77 +1092,57 @@
size_t count, loff_t *ppos)
{
struct hid_debug_list *list = file->private_data;
- int ret = 0, len;
+ int ret = 0, copied;
DECLARE_WAITQUEUE(wait, current);
mutex_lock(&list->read_mutex);
- while (ret == 0) {
- if (list->head == list->tail) {
- add_wait_queue(&list->hdev->debug_wait, &wait);
- set_current_state(TASK_INTERRUPTIBLE);
+ if (kfifo_is_empty(&list->hid_debug_fifo)) {
+ add_wait_queue(&list->hdev->debug_wait, &wait);
+ set_current_state(TASK_INTERRUPTIBLE);
- while (list->head == list->tail) {
- if (file->f_flags & O_NONBLOCK) {
- ret = -EAGAIN;
- break;
- }
- if (signal_pending(current)) {
- ret = -ERESTARTSYS;
- break;
- }
-
- if (!list->hdev || !list->hdev->debug) {
- ret = -EIO;
- set_current_state(TASK_RUNNING);
- goto out;
- }
-
- /* allow O_NONBLOCK from other threads */
- mutex_unlock(&list->read_mutex);
- schedule();
- mutex_lock(&list->read_mutex);
- set_current_state(TASK_INTERRUPTIBLE);
+ while (kfifo_is_empty(&list->hid_debug_fifo)) {
+ if (file->f_flags & O_NONBLOCK) {
+ ret = -EAGAIN;
+ break;
}
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&list->hdev->debug_wait, &wait);
+ if (signal_pending(current)) {
+ ret = -ERESTARTSYS;
+ break;
+ }
+
+ /* if list->hdev is NULL we cannot remove_wait_queue().
+ * if list->hdev->debug is 0 then hid_debug_unregister()
+ * was already called and list->hdev is being destroyed.
+ * if we add remove_wait_queue() here we can hit a race.
+ */
+ if (!list->hdev || !list->hdev->debug) {
+ ret = -EIO;
+ set_current_state(TASK_RUNNING);
+ goto out;
+ }
+
+ /* allow O_NONBLOCK from other threads */
+ mutex_unlock(&list->read_mutex);
+ schedule();
+ mutex_lock(&list->read_mutex);
+ set_current_state(TASK_INTERRUPTIBLE);
}
+ __set_current_state(TASK_RUNNING);
+ remove_wait_queue(&list->hdev->debug_wait, &wait);
+
if (ret)
goto out;
-
- /* pass the ringbuffer contents to userspace */
-copy_rest:
- if (list->tail == list->head)
- goto out;
- if (list->tail > list->head) {
- len = list->tail - list->head;
- if (len > count)
- len = count;
-
- if (copy_to_user(buffer + ret, &list->hid_debug_buf[list->head], len)) {
- ret = -EFAULT;
- goto out;
- }
- ret += len;
- list->head += len;
- } else {
- len = HID_DEBUG_BUFSIZE - list->head;
- if (len > count)
- len = count;
-
- if (copy_to_user(buffer, &list->hid_debug_buf[list->head], len)) {
- ret = -EFAULT;
- goto out;
- }
- list->head = 0;
- ret += len;
- count -= len;
- if (count > 0)
- goto copy_rest;
- }
-
}
+
+ /* pass the fifo content to userspace, locking is not needed with only
+ * one concurrent reader and one concurrent writer
+ */
+ ret = kfifo_to_user(&list->hid_debug_fifo, buffer, count, &copied);
+ if (ret)
+ goto out;
+ ret = copied;
out:
mutex_unlock(&list->read_mutex);
return ret;
@@ -1190,7 +1153,7 @@
struct hid_debug_list *list = file->private_data;
poll_wait(file, &list->hdev->debug_wait, wait);
- if (list->head != list->tail)
+ if (!kfifo_is_empty(&list->hid_debug_fifo))
return EPOLLIN | EPOLLRDNORM;
if (!list->hdev->debug)
return EPOLLERR | EPOLLHUP;
@@ -1205,18 +1168,13 @@
spin_lock_irqsave(&list->hdev->debug_list_lock, flags);
list_del(&list->node);
spin_unlock_irqrestore(&list->hdev->debug_list_lock, flags);
- kfree(list->hid_debug_buf);
+ kfifo_free(&list->hid_debug_fifo);
kfree(list);
return 0;
}
-static const struct file_operations hid_debug_rdesc_fops = {
- .open = hid_debug_rdesc_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = single_release,
-};
+DEFINE_SHOW_ATTRIBUTE(hid_debug_rdesc);
static const struct file_operations hid_debug_events_fops = {
.owner = THIS_MODULE,
@@ -1256,4 +1214,3 @@
{
debugfs_remove_recursive(hid_debug_root);
}
-