From: xiao jin <jin.xiao@xxxxxxxxx>
Date: Tue, 8 Oct 2013 16:57:29 +0800
Subject: [PATCH] cdc-acm: put delayed_wb to list
If acm_write_start during acm suspend, write acm_wb is backuped
to delayed_wb. When acm resume, the delayed_wb will be started.
This mechanism can only record one write during acm suspend. More
acm write will be abandoned.
This patch is to use list_head to record the write acm_wb during acm
suspend. It can ensure no acm write abandoned.
Signed-off-by: xiao jin <jin.xiao@xxxxxxxxx>
---
drivers/usb/class/cdc-acm.c | 30 ++++++++++++++++++++----------
drivers/usb/class/cdc-acm.h | 7 ++++++-
2 files changed, 26 insertions(+), 11 deletions(-)
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 9f49bfe..be679be 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -607,6 +607,7 @@ static int acm_tty_write(struct tty_struct *tty,
unsigned long flags;
int wbn;
struct acm_wb *wb;
+ struct delayed_wb *d_wb;
if (!count)
return 0;
@@ -634,12 +635,17 @@ static int acm_tty_write(struct tty_struct *tty,
usb_autopm_get_interface_async(acm->control);
if (acm->susp_count) {
- if (!acm->delayed_wb)
- acm->delayed_wb = wb;
- else
+ d_wb = kmalloc(sizeof(struct delayed_wb), GFP_ATOMIC);
+ if (d_wb == NULL) {
usb_autopm_put_interface_async(acm->control);
- spin_unlock_irqrestore(&acm->write_lock, flags);
- return count; /* A white lie */
+ spin_unlock_irqrestore(&acm->write_lock, flags);
+ return -ENOMEM;
+ } else {
+ d_wb->wb = wb;
+ list_add_tail(&d_wb->list, &acm->delayed_wb_list);
+ spin_unlock_irqrestore(&acm->write_lock, flags);
+ return count; /* A white lie */
+ }
}
usb_mark_last_busy(acm->dev);
@@ -1255,6 +1261,7 @@ made_compressed_probe:
snd->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
snd->instance = acm;
}
+ INIT_LIST_HEAD(&acm->delayed_wb_list);
usb_set_intfdata(intf, acm);
@@ -1449,6 +1456,7 @@ static int acm_resume(struct usb_interface *intf)
{
struct acm *acm = usb_get_intfdata(intf);
struct acm_wb *wb;
+ struct delayed_wb *d_wb, *nd_wb;
int rv = 0;
int cnt;
@@ -1464,14 +1472,16 @@ static int acm_resume(struct usb_interface
*intf)
rv = usb_submit_urb(acm->ctrlurb, GFP_NOIO);
spin_lock_irq(&acm->write_lock);
- if (acm->delayed_wb) {
- wb = acm->delayed_wb;
- acm->delayed_wb = NULL;
+ list_for_each_entry_safe(d_wb, nd_wb,
+ &acm->delayed_wb_list, list) {
+ wb = d_wb->wb;
+ list_del(&d_wb->list);
+ kfree(d_wb);
spin_unlock_irq(&acm->write_lock);
acm_start_wb(acm, wb);
- } else {
- spin_unlock_irq(&acm->write_lock);
+ spin_lock_irq(&acm->write_lock);
}
+ spin_unlock_irq(&acm->write_lock);
/*
* delayed error checking because we must
diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index 0f76e4a..5eed93f 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -79,6 +79,11 @@ struct acm_rb {
struct acm *instance;
};
+struct delayed_wb {
+ struct list_head list;
+ struct acm_wb *wb;
+}
+
struct acm {
struct usb_device *dev; /* the corresponding usb device */
struct usb_interface *control; /* control interface */
@@ -117,7 +122,7 @@ struct acm {
unsigned int throttled:1; /* actually throttled */
unsigned int throttle_req:1; /* throttle requested */
u8 bInterval;
- struct acm_wb *delayed_wb; /* write queued for a device about to be
woken */
+ struct list_head delayed_wb_list; /* delayed wb list */
};
#define CDC_DATA_INTERFACE_TYPE 0x0a
--
1.7.1
--
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