Make the code looks less like Pascal.
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), 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(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. + * - 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...) + */ +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,
On Wed, Jun 21, 2023 at 11:42:30AM +0200, Benjamin Tissoires wrote:
Make the code looks less like Pascal.
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), 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)
__must_hold(&hidpp->send_mutex) ?
On Jun 21 2023, Greg KH wrote:
On Wed, Jun 21, 2023 at 11:42:30AM +0200, Benjamin Tissoires wrote:
Make the code looks less like Pascal.
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), 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)
__must_hold(&hidpp->send_mutex) ?
Good point. I'll add this in v2.
I'm still waiting for some feedback from the people who particpated in the original BZ, but the new bug is harder to reproduce. Anyway, there is no rush IMO.
Cheers, Benjamin
On Fri, 2023-06-23 at 10:37 +0200, Benjamin Tissoires wrote:
On Jun 21 2023, Greg KH wrote:
On Wed, Jun 21, 2023 at 11:42:30AM +0200, Benjamin Tissoires wrote:
Make the code looks less like Pascal.
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), 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)
__must_hold(&hidpp->send_mutex) ?
Good point. I'll add this in v2.
I'm still waiting for some feedback from the people who particpated in the original BZ, but the new bug is harder to reproduce. Anyway, there is no rush IMO.
The problem is only ever going to show up in very limited circumstances after the logic fix was applied.
You need a hardware problem (such as the controller being too busy to answer) to trigger the problems fixed by this patch. I don't see a way to reliably reproduce it unless you inject that hardware error.
On Sun, Jun 25, 2023 at 10:30 AM Bastien Nocera hadess@hadess.net wrote:
On Fri, 2023-06-23 at 10:37 +0200, Benjamin Tissoires wrote:
On Jun 21 2023, Greg KH wrote:
On Wed, Jun 21, 2023 at 11:42:30AM +0200, Benjamin Tissoires wrote:
Make the code looks less like Pascal.
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), 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)
__must_hold(&hidpp->send_mutex) ?
Good point. I'll add this in v2.
I'm still waiting for some feedback from the people who particpated in the original BZ, but the new bug is harder to reproduce. Anyway, there is no rush IMO.
The problem is only ever going to show up in very limited circumstances after the logic fix was applied.
You need a hardware problem (such as the controller being too busy to answer) to trigger the problems fixed by this patch. I don't see a way to reliably reproduce it unless you inject that hardware error.
Some people on the Bz were able to reproduce with multiple reboots. But it's not as urgent as previously, and we were close to the 6.4 final when I sent it. I'll make sure this goes into 6.5 and gets proper stable backports FWIW.
Cheers, Benjamin
On 26.06.23 16:02, Benjamin Tissoires wrote:
On Sun, Jun 25, 2023 at 10:30 AM Bastien Nocera hadess@hadess.net wrote:
On Fri, 2023-06-23 at 10:37 +0200, Benjamin Tissoires wrote:
On Jun 21 2023, Greg KH wrote:
On Wed, Jun 21, 2023 at 11:42:30AM +0200, Benjamin Tissoires wrote:
Make the code looks less like Pascal.
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), 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(-)
[...]
Some people on the Bz were able to reproduce with multiple reboots. But it's not as urgent as previously, and we were close to the 6.4 final when I sent it. I'll make sure this goes into 6.5 and gets proper stable backports FWIW.
Did that happen? Doesn't look like it from here, but maybe I'm missing something. Where there maybe other changes to resolve the remaining problems some users encounter sporadically since the urgent fixes went in?
Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) -- Everything you wanna know about Linux kernel regression tracking: https://linux-regtracking.leemhuis.info/about/#tldr If I did something stupid, please tell me, as explained on that page.
On Tue, Jul 11, 2023 at 3:10 PM Linux regression tracking (Thorsten Leemhuis) regressions@leemhuis.info wrote:
On 26.06.23 16:02, Benjamin Tissoires wrote:
On Sun, Jun 25, 2023 at 10:30 AM Bastien Nocera hadess@hadess.net wrote:
On Fri, 2023-06-23 at 10:37 +0200, Benjamin Tissoires wrote:
On Jun 21 2023, Greg KH wrote:
On Wed, Jun 21, 2023 at 11:42:30AM +0200, Benjamin Tissoires wrote:
Make the code looks less like Pascal.
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), 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(-)
[...]
Some people on the Bz were able to reproduce with multiple reboots. But it's not as urgent as previously, and we were close to the 6.4 final when I sent it. I'll make sure this goes into 6.5 and gets proper stable backports FWIW.
Did that happen? Doesn't look like it from here, but maybe I'm missing something. Where there maybe other changes to resolve the remaining problems some users encounter sporadically since the urgent fixes went in?
No, there were no other changes that could have solved this. I guess the randomness of the problem makes it way harder to detect and to reproduce.
I'll send a v2 of that patch with the reviews today or tomorrow and we can probably get it through the current 6.5 cycle.
Cheers, Benjamin
Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
Everything you wanna know about Linux kernel regression tracking: https://linux-regtracking.leemhuis.info/about/#tldr If I did something stupid, please tell me, as explained on that page.
On 11.07.23 15:40, Benjamin Tissoires wrote:
On Tue, Jul 11, 2023 at 3:10 PM Linux regression tracking (Thorsten Leemhuis) regressions@leemhuis.info wrote:
On 26.06.23 16:02, Benjamin Tissoires wrote:
On Sun, Jun 25, 2023 at 10:30 AM Bastien Nocera hadess@hadess.net wrote:
On Fri, 2023-06-23 at 10:37 +0200, Benjamin Tissoires wrote:
On Jun 21 2023, Greg KH wrote:
On Wed, Jun 21, 2023 at 11:42:30AM +0200, Benjamin Tissoires wrote: > Make the code looks less like Pascal. > > 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), > 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(-)
[...]
Some people on the Bz were able to reproduce with multiple reboots. But it's not as urgent as previously, and we were close to the 6.4 final when I sent it. I'll make sure this goes into 6.5 and gets proper stable backports FWIW.
Did that happen? Doesn't look like it from here, but maybe I'm missing something. Where there maybe other changes to resolve the remaining problems some users encounter sporadically since the urgent fixes went in?
No, there were no other changes that could have solved this. I guess the randomness of the problem makes it way harder to detect and to reproduce.
I'll send a v2 of that patch with the reviews today or tomorrow and we can probably get it through the current 6.5 cycle.
Great, many thx!
Ciao, Thorsten
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.
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(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.
- 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()?
If we do, why don't also do it for hidpp_send_fap_command_sync() and hidpp_send_rap_command_sync(), or their callers?
If it's absolutely necessary, a "see __do_hidpp_send_message_sync()" should be enough.
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
- */
+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,
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,
linux-stable-mirror@lists.linaro.org
-
Bastien Nocera -
Benjamin Tissoires -
Greg KH -
Linux regression tracking (Thorsten Leemhuis)