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When ufshcd_clk_scaling_suspend_work (thread A) running and new command coming, ufshcd_clk_scaling_start_busy (thread B) may get host_lock after thread A first time release host_lock. Then thread A second time get host_lock will set clk_scaling.window_start_t = 0 which scale up clock abnormal next polling_ms time. Also inlines another __ufshcd_suspend_clkscaling calls. Below is racing step: 1 hba->clk_scaling.suspend_work (Thread A) ufshcd_clk_scaling_suspend_work 2 spin_lock_irqsave(hba->host->host_lock, irq_flags); 3 hba->clk_scaling.is_suspended = true; 4 spin_unlock_irqrestore(hba->host->host_lock, irq_flags); __ufshcd_suspend_clkscaling 7 spin_lock_irqsave(hba->host->host_lock, flags); 8 hba->clk_scaling.window_start_t = 0; 9 spin_unlock_irqrestore(hba->host->host_lock, flags); ufshcd_send_command (Thread B) ufshcd_clk_scaling_start_busy 5 spin_lock_irqsave(hba->host->host_lock, flags); .... 6 spin_unlock_irqrestore(hba->host->host_lock, flags); Signed-off-by: Peter Wang <peter.wang@mediatek.com> Link: https://lore.kernel.org/r/20230831130826.5592-3-peter.wang@mediatek.com Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.