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authorAndrey Smirnov <andrew.smirnov@gmail.com>2019-05-13 16:59:08 -0700
committerSascha Hauer <s.hauer@pengutronix.de>2019-05-15 10:09:41 +0200
commite6a025abdd2fcd60962d8f6a1f52048e52e35c78 (patch)
tree78adf618a7ed404cbe9e15f77396f2777f0f7a68
parente0600e1fe20856cfbefb2d8f798076c7694a9e24 (diff)
downloadbarebox-e6a025abdd2fcd60962d8f6a1f52048e52e35c78.tar.gz
serdev: Do not call .receive_buf() callback recursively
Code implementing .receive_buf() callback can potentially call serdev_device_write(), which will call serdev_device_poller(). We need to make sure that such a call is a no-op in order to prevent corrupting shared data buffer as well as breaking .receive_buf callback that most likely does not expect that to happen. Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com> Tested-by: Cory Tusar <cory.tusar@zii.aero> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
-rw-r--r--common/serdev.c6
-rw-r--r--include/serdev.h2
2 files changed, 8 insertions, 0 deletions
diff --git a/common/serdev.c b/common/serdev.c
index 4a6dbef..3e0da08 100644
--- a/common/serdev.c
+++ b/common/serdev.c
@@ -9,6 +9,10 @@ static void serdev_device_poller(void *context)
unsigned char *buf = serdev->buf;
int ret, len;
+ if (serdev->locked)
+ return;
+
+ serdev->locked = true;
/*
* Since this callback is a part of poller infrastructure we
* want to use _non_interruptible version of the function
@@ -37,6 +41,8 @@ static void serdev_device_poller(void *context)
} else {
poller_async_cancel(&serdev->poller);
}
+
+ serdev->locked = false;
}
static int serdev_device_set_polling_interval(struct param_d *param, void *serdev)
diff --git a/include/serdev.h b/include/serdev.h
index f5d34f5..2903053 100644
--- a/include/serdev.h
+++ b/include/serdev.h
@@ -14,6 +14,7 @@
* @poller Async poller used to poll this serdev
* @polling_interval: Async poller periodicity
* @polling_window: Duration of a single busy loop poll
+ * @locked: Lock to prevent recursive polling
* @receive_buf: Function called with data received from device;
* returns number of bytes accepted;
*/
@@ -24,6 +25,7 @@ struct serdev_device {
struct poller_async poller;
uint64_t polling_interval;
uint64_t polling_window;
+ bool locked;
int (*receive_buf)(struct serdev_device *, const unsigned char *,
size_t);