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FROMLIST: scsi: ufs: fix clkgating on/off correctly

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The below call stack prevents clk_gating at every IO completion.
We can remove the condition, ufshcd_any_tag_in_use(), since clkgating_work
will check it again.

ufshcd_complete_requests(struct ufs_hba *hba)
  ufshcd_transfer_req_compl()
    __ufshcd_transfer_req_compl()
      __ufshcd_release(hba)
        if (ufshcd_any_tag_in_use() == 1)
           return;
  ufshcd_tmc_handler(hba);
    blk_mq_tagset_busy_iter();

Note that, this still requires a work to deal with a potential racy condition
when user sets clkgating.delay_ms to very small value. That can cause preventing
clkgating by the check of ufshcd_any_tag_in_use() in gate_work.

Link: https://lore.kernel.org/linux-scsi/20201028194352.GA3060274@google.com/T/#m3485ba8df14e4ad5cf0aa5b314ffe1cb90d90105
Fixes: 7252a36030 ("scsi: ufs: Avoid busy-waiting by eliminating tag conflicts")
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>
Change-Id: I9b56725b26e1be8b1da55ae1db7322ab00fc5298
This commit is contained in:
Jaegeuk Kim
2020-10-15 22:57:41 -07:00
committed by Jaegeuk Kim
parent 268635d8ed
commit 66692a44e7
1 changed files with 1 additions and 1 deletions
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2
drivers/scsi/ufs/ufshcd.c
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@@ -1745,7 +1745,7 @@ static void __ufshcd_release(struct ufs_hba *hba)
if (hba->clk_gating.active_reqs || hba->clk_gating.is_suspended ||
hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL ||
ufshcd_any_tag_in_use(hba) || hba->outstanding_tasks ||
hba->outstanding_tasks ||
hba->active_uic_cmd || hba->uic_async_done ||
hba->clk_gating.state == CLKS_OFF)
return;