From: Benjamin Tissoires benjamin.tissoires@redhat.com
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@vger.kernel.org Reviewed-by: Bastien Nocera hadess@hadess.net Signed-off-by: Benjamin Tissoires benjamin.tissoires@redhat.com --- as requested by https://lore.kernel.org/all/CAHk-=wiMbF38KCNhPFiargenpSBoecSXTLQACKS2UMyo_Vu... 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@redhat.c... --- 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,