[ Upstream commit 5cb37a26355d79ab290220677b1b57d28e99a895 ] hba->outstanding_tasks, which is read under host_lock spinlock, tells the interrupt handler what task management tags are in use by the driver. The doorbell register bits indicate which tags are in use by the hardware. A doorbell bit that is 0 is because the bit has yet to be set by the driver, or because the task is complete. It is only possible to disambiguate the 2 cases, if reading/writing the doorbell register is synchronized with reading/writing hba->outstanding_tasks. For that reason, reading REG_UTP_TASK_REQ_DOOR_BELL must be done under spinlock. Link: https://lore.kernel.org/r/20211108064815.569494-3-adrian.hunter@intel.com Fixes: f5ef336fd2e4 ("scsi: ufs: core: Fix task management completion") Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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.
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