Re: [PATCH 5.10.y 1/3] rtc: Improve performance of rtc_time64_to_tm(). Add tests.

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
⚠️ Found follow-up fixes in mainline

The upstream commit SHA1 provided is correct: 1d1bb12a8b1805ddeef9793ebeb920179fb0fa38

WARNING: Author mismatch between patch and upstream commit:
Backport author: <u.kleine-koenig@baylibre.com>
Commit author: Cassio Neri<cassio.neri@gmail.com>

Status in newer kernel trees:
6.15.y | Present (exact SHA1)
6.14.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Present (exact SHA1)
6.1.y | Present (exact SHA1)
5.15.y | Present (exact SHA1)

Found fixes commits:
8a904a3caa88 rtc: test: Fix invalid format specifier.

Note: The patch differs from the upstream commit:
---
1:  1d1bb12a8b180 ! 1:  b0856f15968b7 rtc: Improve performance of rtc_time64_to_tm(). Add tests.
    @@ Metadata
      ## Commit message ##
         rtc: Improve performance of rtc_time64_to_tm(). Add tests.
     
    +    commit 1d1bb12a8b1805ddeef9793ebeb920179fb0fa38 upstream.
    +
         The current implementation of rtc_time64_to_tm() contains unnecessary
         loops, branches and look-up tables. The new one uses an arithmetic-based
         algorithm appeared in [1] and is approximately 4.3 times faster (YMMV).
    @@ Commit message
         Reported-by: kernel test robot <lkp@intel.com>
         Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
         Link: https://lore.kernel.org/r/20210624201343.85441-1-cassio.neri@gmail.com
    +    Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
     
      ## drivers/rtc/Kconfig ##
     @@ drivers/rtc/Kconfig: config RTC_MC146818_LIB
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.10.y       |  Success    |  Success   |