[PATCH] gattrib: Fix a premature response timer removal

[PATCH] gattrib: Fix a premature response timer removal

[Ido Yariv]

A timer is set when a response is expected. The timer is removed when
data is received, regardless of whether or not the data is a response.
As a result, the timer may be cleared even though a response was not
received and there would be no way to detect a command timeout.

Fix this by clearing the timer only after verifying a response was
received.
---
 attrib/gattrib.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/attrib/gattrib.c b/attrib/gattrib.c
index 29c3585..a1e29a1 100644
--- a/attrib/gattrib.c
+++ b/attrib/gattrib.c
@@ -361,11 +361,6 @@ static gboolean received_data(GIOChannel *io, GIOCondition cond, gpointer data)
 	if (attrib->stale)
 		return FALSE;
 
-	if (attrib->timeout_watch > 0) {
-		g_source_remove(attrib->timeout_watch);
-		attrib->timeout_watch = 0;
-	}
-
 	if (cond & (G_IO_HUP | G_IO_ERR | G_IO_NVAL)) {
 		attrib->read_watch = 0;
 		return FALSE;
@@ -393,6 +388,11 @@ static gboolean received_data(GIOChannel *io, GIOCondition cond, gpointer data)
 	if (is_response(buf[0]) == FALSE)
 		return TRUE;
 
+	if (attrib->timeout_watch > 0) {
+		g_source_remove(attrib->timeout_watch);
+		attrib->timeout_watch = 0;
+	}
+
 	cmd = g_queue_pop_head(attrib->requests);
 	if (cmd == NULL) {
 		/* Keep the watch if we have events to report */
-- 
1.7.7.6

Re: [PATCH] gattrib: Fix a premature response timer removal

[Vinicius Costa Gomes]

Hi Ido,

On 13:56 Wed 06 Jun, Ido Yariv wrote:
> A timer is set when a response is expected. The timer is removed when
> data is received, regardless of whether or not the data is a response.
> As a result, the timer may be cleared even though a response was not
> received and there would be no way to detect a command timeout.
> 
> Fix this by clearing the timer only after verifying a response was
> received.

The patch looks good.

Just a little background on how things are done this way. This was
written thinking that when a indication (a request) is received the
timer should be reset, even if there is already a pending response.

So with this patch we trust that BlueZ will send responses in time, and
we only handle timeouts from the remote. Which is a good assumption for
me. At least it is more consistent.

Here's my Ack.

> ---
>  attrib/gattrib.c |   10 +++++-----
>  1 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/attrib/gattrib.c b/attrib/gattrib.c
> index 29c3585..a1e29a1 100644
> --- a/attrib/gattrib.c
> +++ b/attrib/gattrib.c
> @@ -361,11 +361,6 @@ static gboolean received_data(GIOChannel *io, GIOCondition cond, gpointer data)
>  	if (attrib->stale)
>  		return FALSE;
>  
> -	if (attrib->timeout_watch > 0) {
> -		g_source_remove(attrib->timeout_watch);
> -		attrib->timeout_watch = 0;
> -	}
> -
>  	if (cond & (G_IO_HUP | G_IO_ERR | G_IO_NVAL)) {
>  		attrib->read_watch = 0;
>  		return FALSE;
> @@ -393,6 +388,11 @@ static gboolean received_data(GIOChannel *io, GIOCondition cond, gpointer data)
>  	if (is_response(buf[0]) == FALSE)
>  		return TRUE;
>  
> +	if (attrib->timeout_watch > 0) {
> +		g_source_remove(attrib->timeout_watch);
> +		attrib->timeout_watch = 0;
> +	}
> +
>  	cmd = g_queue_pop_head(attrib->requests);
>  	if (cmd == NULL) {
>  		/* Keep the watch if we have events to report */
> -- 
> 1.7.7.6
> 
> --
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Cheers,
-- 
Vinicius

Re: [PATCH] gattrib: Fix a premature response timer removal

[Johan Hedberg]

Hi Ido,

On Wed, Jun 06, 2012, Ido Yariv wrote:
> A timer is set when a response is expected. The timer is removed when
> data is received, regardless of whether or not the data is a response.
> As a result, the timer may be cleared even though a response was not
> received and there would be no way to detect a command timeout.
> 
> Fix this by clearing the timer only after verifying a response was
> received.
> ---
>  attrib/gattrib.c |   10 +++++-----
>  1 files changed, 5 insertions(+), 5 deletions(-)

Applied. Thanks.

Johan