On 2020-07-13 19:28, Can Guo wrote: > The scsi_block_reqs_cnt increased in ufshcd_hold() is supposed to be > decreased back in ufshcd_ungate_work() in a paired way. However, if > specific ufshcd_hold/release sequences are met, it is possible that > scsi_block_reqs_cnt is increased twice but only one ungate work is > queued. To make sure scsi_block_reqs_cnt is handled by ufshcd_hold() and > ufshcd_ungate_work() in a paired way, increase it only if queue_work() > returns true. > > Signed-off-by: Can Guo <[email protected]> > --- > drivers/scsi/ufs/ufshcd.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c > index ebf7a95..33214bb 100644 > --- a/drivers/scsi/ufs/ufshcd.c > +++ b/drivers/scsi/ufs/ufshcd.c > @@ -1611,12 +1611,12 @@ int ufshcd_hold(struct ufs_hba *hba, bool async) > */ > /* fallthrough */ > case CLKS_OFF: > - ufshcd_scsi_block_requests(hba); > hba->clk_gating.state = REQ_CLKS_ON; > trace_ufshcd_clk_gating(dev_name(hba->dev), > hba->clk_gating.state); > - queue_work(hba->clk_gating.clk_gating_workq, > - &hba->clk_gating.ungate_work); > + if (queue_work(hba->clk_gating.clk_gating_workq, > + &hba->clk_gating.ungate_work)) > + ufshcd_scsi_block_requests(hba); > /* > * fall through to check if we should wait for this > * work to be done or not.
Since "ungate_work" involves calling ufshcd_scsi_unblock_requests() and since this patch changes the order in which ufshcd_scsi_block_requests() and queue_work() are called, I think this patch introduces a race condition. Has it been considered to leave the ufshcd_scsi_block_requests() call where it is and to call ufshcd_scsi_unblock_requests() if queue_work() fails? Thanks, Bart.
