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authorDavid Brownell <dbrownell@users.sourceforge.net>2008-08-06 18:44:12 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2008-08-13 17:32:57 -0700
commit934da4635c2d05cef474e5243ef05df95b2ad264 (patch)
tree0ce5d1645e8e6c79253e0b1133d65800122547e1 /drivers
parent672c4e1843c54227ff1bdf1fdd96f9c45c56aa85 (diff)
usb: cdc-acm: stop dropping tx buffers
The "increase cdc-acm write throughput" patch left in place two now-obsolete mechanisms, either of which can make the cdc-acm driver drop TX data (nasty!). This patch removes them: - The write_ready flag ... if an URB and buffer were found, they can (and should!) always be used. - TX path acm_wb_is_used() ... used when the buffer was just allocated, so that check is pointless. Also fix a won't-yet-matter leak of a write buffer on a disconnect path. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: David Engraf <david.engraf@netcom.eu> Acked-by: Oliver Neukum <oneukum@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/usb/class/cdc-acm.c32
-rw-r--r--drivers/usb/class/cdc-acm.h2
2 files changed, 3 insertions, 31 deletions
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 910247d191e..a9dd28f446d 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -144,11 +144,6 @@ static int acm_wb_is_avail(struct acm *acm)
return n;
}
-static inline int acm_wb_is_used(struct acm *acm, int wbn)
-{
- return acm->wb[wbn].use;
-}
-
/*
* Finish write.
*/
@@ -157,7 +152,6 @@ static void acm_write_done(struct acm *acm, struct acm_wb *wb)
unsigned long flags;
spin_lock_irqsave(&acm->write_lock, flags);
- acm->write_ready = 1;
wb->use = 0;
acm->transmitting--;
spin_unlock_irqrestore(&acm->write_lock, flags);
@@ -190,40 +184,25 @@ static int acm_start_wb(struct acm *acm, struct acm_wb *wb)
static int acm_write_start(struct acm *acm, int wbn)
{
unsigned long flags;
- struct acm_wb *wb;
+ struct acm_wb *wb = &acm->wb[wbn];
int rc;
spin_lock_irqsave(&acm->write_lock, flags);
if (!acm->dev) {
+ wb->use = 0;
spin_unlock_irqrestore(&acm->write_lock, flags);
return -ENODEV;
}
- if (!acm->write_ready) {
- spin_unlock_irqrestore(&acm->write_lock, flags);
- return 0; /* A white lie */
- }
-
- wb = &acm->wb[wbn];
- if(acm_wb_is_avail(acm) <= 1)
- acm->write_ready = 0;
-
dbg("%s susp_count: %d", __func__, acm->susp_count);
if (acm->susp_count) {
- acm->old_ready = acm->write_ready;
acm->delayed_wb = wb;
- acm->write_ready = 0;
schedule_work(&acm->waker);
spin_unlock_irqrestore(&acm->write_lock, flags);
return 0; /* A white lie */
}
usb_mark_last_busy(acm->dev);
- if (!acm_wb_is_used(acm, wbn)) {
- spin_unlock_irqrestore(&acm->write_lock, flags);
- return 0;
- }
-
rc = acm_start_wb(acm, wb);
spin_unlock_irqrestore(&acm->write_lock, flags);
@@ -512,7 +491,6 @@ static void acm_softint(struct work_struct *work)
static void acm_waker(struct work_struct *waker)
{
struct acm *acm = container_of(waker, struct acm, waker);
- unsigned long flags;
int rv;
rv = usb_autopm_get_interface(acm->control);
@@ -524,9 +502,6 @@ static void acm_waker(struct work_struct *waker)
acm_start_wb(acm, acm->delayed_wb);
acm->delayed_wb = NULL;
}
- spin_lock_irqsave(&acm->write_lock, flags);
- acm->write_ready = acm->old_ready;
- spin_unlock_irqrestore(&acm->write_lock, flags);
usb_autopm_put_interface(acm->control);
}
@@ -697,7 +672,7 @@ static int acm_tty_write_room(struct tty_struct *tty)
* Do not let the line discipline to know that we have a reserve,
* or it might get too enthusiastic.
*/
- return (acm->write_ready && acm_wb_is_avail(acm)) ? acm->writesize : 0;
+ return acm_wb_is_avail(acm) ? acm->writesize : 0;
}
static int acm_tty_chars_in_buffer(struct tty_struct *tty)
@@ -1076,7 +1051,6 @@ skip_normal_probe:
spin_lock_init(&acm->write_lock);
spin_lock_init(&acm->read_lock);
mutex_init(&acm->mutex);
- acm->write_ready = 1;
acm->rx_endpoint = usb_rcvbulkpipe(usb_dev, epread->bEndpointAddress);
buf = usb_buffer_alloc(usb_dev, ctrlsize, GFP_KERNEL, &acm->ctrl_dma);
diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index 85c3aaaab7c..94266362ca6 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -106,8 +106,6 @@ struct acm {
struct list_head spare_read_bufs;
struct list_head filled_read_bufs;
int write_used; /* number of non-empty write buffers */
- int write_ready; /* write urb is not running */
- int old_ready;
int processing;
int transmitting;
spinlock_t write_lock;