[PATCH 6.1 0656/1146] scsi: ufs: core: Fix the polling implementation

Greg Kroah-Hartman
2022-12-28T16:22:58Z

From: Bart Van Assche <bvanassche@acm.org>

[ Upstream commit ee8c88cab4afbd5ee10a127d6cbecd6b200185a5 ]

Fix the following issues in ufshcd_poll():

- If polling succeeds, return a positive value.

- Do not complete polling requests from interrupt context because the
block layer expects these requests to be completed from thread
context. From block/bio.c:

If REQ_ALLOC_CACHE is set, the final put of the bio MUST be done from
process context, not hard/soft IRQ.

Fixes: eaab9b573054 ("scsi: ufs: Implement polling support")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20221118233717.441298-1-bvanassche@acm.org
Reviewed-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>
---
drivers/ufs/core/ufshcd.c | 28 ++++++++++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index b1f59a5fe632..5432be4cd0ed 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -5382,6 +5382,26 @@ static void __ufshcd_transfer_req_compl(struct ufs_hba *hba,
}
}

+/* Any value that is not an existing queue number is fine for this constant. */
+enum {
+ UFSHCD_POLL_FROM_INTERRUPT_CONTEXT = -1
+};
+
+static void ufshcd_clear_polled(struct ufs_hba *hba,
+ unsigned long *completed_reqs)
+{
+ int tag;
+
+ for_each_set_bit(tag, completed_reqs, hba->nutrs) {
+ struct scsi_cmnd *cmd = hba->lrb[tag].cmd;
+
+ if (!cmd)
+ continue;
+ if (scsi_cmd_to_rq(cmd)->cmd_flags & REQ_POLLED)
+ __clear_bit(tag, completed_reqs);
+ }
+}
+
/*
* Returns > 0 if one or more commands have been completed or 0 if no
* requests have been completed.
@@ -5398,13 +5418,17 @@ static int ufshcd_poll(struct Scsi_Host *shost, unsigned int queue_num)
WARN_ONCE(completed_reqs & ~hba->outstanding_reqs,
"completed: %#lx; outstanding: %#lx\n", completed_reqs,
hba->outstanding_reqs);
+ if (queue_num == UFSHCD_POLL_FROM_INTERRUPT_CONTEXT) {
+ /* Do not complete polled requests from interrupt context. */
+ ufshcd_clear_polled(hba, &completed_reqs);
+ }
hba->outstanding_reqs &= ~completed_reqs;
spin_unlock_irqrestore(&hba->outstanding_lock, flags);

if (completed_reqs)
__ufshcd_transfer_req_compl(hba, completed_reqs);

- return completed_reqs;
+ return completed_reqs != 0;
}

/**
@@ -5435,7 +5459,7 @@ static irqreturn_t ufshcd_transfer_req_compl(struct ufs_hba *hba)
* Ignore the ufshcd_poll() return value and return IRQ_HANDLED since we
* do not want polling to trigger spurious interrupt complaints.
*/
- ufshcd_poll(hba->host, 0);
+ ufshcd_poll(hba->host, UFSHCD_POLL_FROM_INTERRUPT_CONTEXT);

return IRQ_HANDLED;
}
--
2.35.1