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Subject[061/289] isdn/gigaset: fix bas_gigaset AT read error handling
2.6.36-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Tilman Schmidt <tilman@imap.cc>

commit c8701a08d6a4efeae45d84d0aa87172f23b14e3c upstream.

Rework the handling of USB errors in AT response reads
to fix a possible infinite retry loop and a memory leak,
and silence a few overly verbose kernel messages.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/isdn/gigaset/bas-gigaset.c | 83 ++++++++++++++-----------------------
1 file changed, 33 insertions(+), 50 deletions(-)
--- a/drivers/isdn/gigaset/bas-gigaset.c
+++ b/drivers/isdn/gigaset/bas-gigaset.c
@@ -438,23 +438,27 @@ static void cmd_in_timeout(unsigned long
return;
}

- if (ucs->retry_cmd_in++ < BAS_RETRY) {
- dev_notice(cs->dev, "control read: timeout, retry %d\n",
- ucs->retry_cmd_in);
- rc = atread_submit(cs, BAS_TIMEOUT);
- if (rc >= 0 || rc == -ENODEV)
- /* resubmitted or disconnected */
- /* - bypass regular exit block */
- return;
- } else {
+ if (ucs->retry_cmd_in++ >= BAS_RETRY) {
dev_err(cs->dev,
"control read: timeout, giving up after %d tries\n",
ucs->retry_cmd_in);
+ kfree(ucs->rcvbuf);
+ ucs->rcvbuf = NULL;
+ ucs->rcvbuf_size = 0;
+ error_reset(cs);
+ return;
+ }
+
+ gig_dbg(DEBUG_USBREQ, "%s: timeout, retry %d",
+ __func__, ucs->retry_cmd_in);
+ rc = atread_submit(cs, BAS_TIMEOUT);
+ if (rc < 0) {
+ kfree(ucs->rcvbuf);
+ ucs->rcvbuf = NULL;
+ ucs->rcvbuf_size = 0;
+ if (rc != -ENODEV)
+ error_reset(cs);
}
- kfree(ucs->rcvbuf);
- ucs->rcvbuf = NULL;
- ucs->rcvbuf_size = 0;
- error_reset(cs);
}

/* read_ctrl_callback
@@ -470,18 +474,11 @@ static void read_ctrl_callback(struct ur
struct cardstate *cs = inbuf->cs;
struct bas_cardstate *ucs = cs->hw.bas;
int status = urb->status;
- int have_data = 0;
unsigned numbytes;
int rc;

update_basstate(ucs, 0, BS_ATRDPEND);
wake_up(&ucs->waitqueue);
-
- if (!ucs->rcvbuf_size) {
- dev_warn(cs->dev, "%s: no receive in progress\n", __func__);
- return;
- }
-
del_timer(&ucs->timer_cmd_in);

switch (status) {
@@ -495,19 +492,10 @@ static void read_ctrl_callback(struct ur
numbytes = ucs->rcvbuf_size;
}

- /* copy received bytes to inbuf */
- have_data = gigaset_fill_inbuf(inbuf, ucs->rcvbuf, numbytes);
-
- if (unlikely(numbytes < ucs->rcvbuf_size)) {
- /* incomplete - resubmit for remaining bytes */
- ucs->rcvbuf_size -= numbytes;
- ucs->retry_cmd_in = 0;
- rc = atread_submit(cs, BAS_TIMEOUT);
- if (rc >= 0 || rc == -ENODEV)
- /* resubmitted or disconnected */
- /* - bypass regular exit block */
- return;
- error_reset(cs);
+ /* copy received bytes to inbuf, notify event layer */
+ if (gigaset_fill_inbuf(inbuf, ucs->rcvbuf, numbytes)) {
+ gig_dbg(DEBUG_INTR, "%s-->BH", __func__);
+ gigaset_schedule_event(cs);
}
break;

@@ -516,37 +504,32 @@ static void read_ctrl_callback(struct ur
case -EINPROGRESS: /* pending */
case -ENODEV: /* device removed */
case -ESHUTDOWN: /* device shut down */
- /* no action necessary */
+ /* no further action necessary */
gig_dbg(DEBUG_USBREQ, "%s: %s",
__func__, get_usb_statmsg(status));
break;

- default: /* severe trouble */
- dev_warn(cs->dev, "control read: %s\n",
- get_usb_statmsg(status));
+ default: /* other errors: retry */
if (ucs->retry_cmd_in++ < BAS_RETRY) {
- dev_notice(cs->dev, "control read: retry %d\n",
- ucs->retry_cmd_in);
+ gig_dbg(DEBUG_USBREQ, "%s: %s, retry %d", __func__,
+ get_usb_statmsg(status), ucs->retry_cmd_in);
rc = atread_submit(cs, BAS_TIMEOUT);
- if (rc >= 0 || rc == -ENODEV)
- /* resubmitted or disconnected */
- /* - bypass regular exit block */
+ if (rc >= 0)
+ /* successfully resubmitted, skip freeing */
return;
- } else {
- dev_err(cs->dev,
- "control read: giving up after %d tries\n",
- ucs->retry_cmd_in);
+ if (rc == -ENODEV)
+ /* disconnect, no further action necessary */
+ break;
}
+ dev_err(cs->dev, "control read: %s, giving up after %d tries\n",
+ get_usb_statmsg(status), ucs->retry_cmd_in);
error_reset(cs);
}

+ /* read finished, free buffer */
kfree(ucs->rcvbuf);
ucs->rcvbuf = NULL;
ucs->rcvbuf_size = 0;
- if (have_data) {
- gig_dbg(DEBUG_INTR, "%s-->BH", __func__);
- gigaset_schedule_event(cs);
- }
}

/* atread_submit



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