On Sun, Jun 25, 2023 at 10:30 AM Bastien Nocera hadess@hadess.net wrote:
On Wed, 2023-06-21 at 11:42 +0200, Benjamin Tissoires wrote:
Make the code looks less like Pascal.
Honestly, while this was written in jest in an email is fine, putting this in the commit message is quite insulting.
The "retry" patch tried to fix real world problems by making minimal code changes, eg. avoiding the review problem that the present patch has, and even then, all of us missed the logic bug.
I also haven't written any Pascal code since 1996.
Apologies for that. I honestly took Linus' remark to myself only, because I was fixing your fix on my original code. And while initially fixing your for loop, I should have realized that this was very hard to follow, because of the "if (sth; sth < 1 && foo && bar; sth+=1)".
I'll amend v2
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 too),
"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 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.
drivers/hid/hid-logitech-hidpp.c | 102 +++++++++++++++++++++++------
1 file changed, 61 insertions(+), 41 deletions(-)
diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid- logitech-hidpp.c index dfe8e09a18de..3d1ffe199f08 100644 --- a/drivers/hid/hid-logitech-hidpp.c +++ b/drivers/hid/hid-logitech-hidpp.c @@ -275,21 +275,20 @@ 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;mutex_lock(&hidpp->send_mutex);
int ret; hidpp->send_receive_buf = response; hidpp->answer_available = false;@@ -300,41 +299,62 @@ 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(structhidpp_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(structhidpp_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.
- 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...)
Do we really need to re-explain the possible return values that were already explained above __do_hidpp_send_message_sync()?
Right, maybe we don't need to duplicate the comment after all.
If we do, why don't also do it for hidpp_send_fap_command_sync() and hidpp_send_rap_command_sync(), or their callers?
In a way it would make sense to do, because this is non standard.
If it's absolutely necessary, a "see __do_hidpp_send_message_sync()" should be enough.
Good point.
I've double-checked that none of the existing callers expected a partially filled in "response" struct on error.
Reviewed-by: Bastien Nocera hadess@hadess.net
Thanks!
Cheers, Benjamin
- */
+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;
base-commit: b98ec211af5508457e2b1c4cc99373630a83fa81 change-id: 20230621-logitech-fixes-a4c0e66ea2ad
Best regards,