Commit ee8c88ca authored by Bart Van Assche's avatar Bart Van Assche Committed by Martin K. Petersen
Browse files

scsi: ufs: core: Fix the polling implementation 



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: eaab9b57 ("scsi: ufs: Implement polling support")
Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20221118233717.441298-1-bvanassche@acm.org


Reviewed-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 4d450cf2

drivers/ufs/core/ufshcd.c

+26 −2
Original line number Diff line number Diff line
@@ -5344,6 +5344,26 @@ 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.
@@ -5360,13 +5380,17 @@ 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;

}



/**
@@ -5397,7 +5421,7 @@ 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;

}