From: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
Extract the internal code inside a helper function, fix the
initialization of the parameters used in the helper function
(`hidpp->answer_available` was not reset and `*response` wasn't either),
and use a `do {...} while();` loop.
Fixes: 586e8fede795 ("HID: logitech-hidpp: Retry commands when device is busy")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Bastien Nocera <hadess@xxxxxxxxxx>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
---
as requested by https://lore.kernel.org/all/CAHk-=wiMbF38KCNhPFiargenpSBoecSXTLQACKS2UMyo_Vu2ww@xxxxxxxxxxxxxx/
This is a rewrite of that particular piece of code.
---
Changes in v2:
- added __must_hold() for KASAN
- Reworked the comment describing the functions and their return values
- Link to v1: https://lore.kernel.org/r/20230621-logitech-fixes-v1-1-32e70933c0b0@xxxxxxxxxx
---
drivers/hid/hid-logitech-hidpp.c | 115 +++++++++++++++++++++++++--------------
1 file changed, 75 insertions(+), 40 deletions(-)
diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 129b01be488d..09ba2086c95c 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -275,21 +275,22 @@ static int __hidpp_send_report(struct hid_device *hdev,
}
/*
- * hidpp_send_message_sync() returns 0 in case of success, and something else
- * in case of a failure.
- * - If ' something else' is positive, that means that an error has been raised
- * by the protocol itself.
- * - If ' something else' is negative, that means that we had a classic error
- * (-ENOMEM, -EPIPE, etc...)
+ * Effectively send the message to the device, waiting for its answer.
+ *
+ * Must be called with hidpp->send_mutex locked
+ *
+ * Same return protocol than hidpp_send_message_sync():
+ * - success on 0
+ * - negative error means transport error
+ * - positive value means protocol error
*/
-static int hidpp_send_message_sync(struct hidpp_device *hidpp,
+static int __do_hidpp_send_message_sync(struct hidpp_device *hidpp,
struct hidpp_report *message,
struct hidpp_report *response)
{
- int ret = -1;
- int max_retries = 3;
+ int ret;
- mutex_lock(&hidpp->send_mutex);
+ __must_hold(&hidpp->send_mutex);
hidpp->send_receive_buf = response;
hidpp->answer_available = false;
@@ -300,47 +301,74 @@ static int hidpp_send_message_sync(struct hidpp_device *hidpp,
*/
*response = *message;
- for (; max_retries != 0 && ret; max_retries--) {
- ret = __hidpp_send_report(hidpp->hid_dev, message);
+ ret = __hidpp_send_report(hidpp->hid_dev, message);
+ if (ret) {
+ dbg_hid("__hidpp_send_report returned err: %d\n", ret);
+ memset(response, 0, sizeof(struct hidpp_report));
+ return ret;
+ }
- if (ret) {
- dbg_hid("__hidpp_send_report returned err: %d\n", ret);
- memset(response, 0, sizeof(struct hidpp_report));
- break;
- }
+ if (!wait_event_timeout(hidpp->wait, hidpp->answer_available,
+ 5*HZ)) {
+ dbg_hid("%s:timeout waiting for response\n", __func__);
+ memset(response, 0, sizeof(struct hidpp_report));
+ return -ETIMEDOUT;
+ }
- if (!wait_event_timeout(hidpp->wait, hidpp->answer_available,
- 5*HZ)) {
- dbg_hid("%s:timeout waiting for response\n", __func__);
- memset(response, 0, sizeof(struct hidpp_report));
- ret = -ETIMEDOUT;
- break;
- }
+ if (response->report_id == REPORT_ID_HIDPP_SHORT &&
+ response->rap.sub_id == HIDPP_ERROR) {
+ ret = response->rap.params[1];
+ dbg_hid("%s:got hidpp error %02X\n", __func__, ret);
+ return ret;
+ }
- if (response->report_id == REPORT_ID_HIDPP_SHORT &&
- response->rap.sub_id == HIDPP_ERROR) {
- ret = response->rap.params[1];
- dbg_hid("%s:got hidpp error %02X\n", __func__, ret);
+ if ((response->report_id == REPORT_ID_HIDPP_LONG ||
+ response->report_id == REPORT_ID_HIDPP_VERY_LONG) &&
+ response->fap.feature_index == HIDPP20_ERROR) {
+ ret = response->fap.params[1];
+ dbg_hid("%s:got hidpp 2.0 error %02X\n", __func__, ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * hidpp_send_message_sync() returns 0 in case of success, and something else
+ * in case of a failure.
+ *
+ * See __do_hidpp_send_message_sync() for a detailed explanation of the returned
+ * value.
+ */
+static int hidpp_send_message_sync(struct hidpp_device *hidpp,
+ struct hidpp_report *message,
+ struct hidpp_report *response)
+{
+ int ret;
+ int max_retries = 3;
+
+ mutex_lock(&hidpp->send_mutex);
+
+ do {
+ ret = __do_hidpp_send_message_sync(hidpp, message, response);
+ if (ret != HIDPP20_ERROR_BUSY)
break;
- }
- if ((response->report_id == REPORT_ID_HIDPP_LONG ||
- response->report_id == REPORT_ID_HIDPP_VERY_LONG) &&
- response->fap.feature_index == HIDPP20_ERROR) {
- ret = response->fap.params[1];
- if (ret != HIDPP20_ERROR_BUSY) {
- dbg_hid("%s:got hidpp 2.0 error %02X\n", __func__, ret);
- break;
- }
- dbg_hid("%s:got busy hidpp 2.0 error %02X, retrying\n", __func__, ret);
- }
- }
+ dbg_hid("%s:got busy hidpp 2.0 error %02X, retrying\n", __func__, ret);
+ } while (--max_retries);
mutex_unlock(&hidpp->send_mutex);
return ret;
}
+/*
+ * hidpp_send_fap_command_sync() returns 0 in case of success, and something else
+ * in case of a failure.
+ *
+ * See __do_hidpp_send_message_sync() for a detailed explanation of the returned
+ * value.
+ */
static int hidpp_send_fap_command_sync(struct hidpp_device *hidpp,
u8 feat_index, u8 funcindex_clientid, u8 *params, int param_count,
struct hidpp_report *response)
@@ -373,6 +401,13 @@ static int hidpp_send_fap_command_sync(struct hidpp_device *hidpp,
return ret;
}
+/*
+ * hidpp_send_rap_command_sync() returns 0 in case of success, and something else
+ * in case of a failure.
+ *
+ * See __do_hidpp_send_message_sync() for a detailed explanation of the returned
+ * value.
+ */
static int hidpp_send_rap_command_sync(struct hidpp_device *hidpp_dev,
u8 report_id, u8 sub_id, u8 reg_address, u8 *params, int param_count,
struct hidpp_report *response)
---
base-commit: 87854366176403438d01f368b09de3ec2234e0f5
change-id: 20230621-logitech-fixes-a4c0e66ea2ad
Best regards,
--
Benjamin Tissoires <bentiss@xxxxxxxxxx>
