Commit 6e0ae74b authored by Narsimhulu Musini's avatar Narsimhulu Musini Committed by Martin K. Petersen
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snic: Handling control path queue issues 



Fix handles control path queue issues such as queue full and sudden
removal of hardware.

Signed-off-by: default avatarNarsimhulu Musini <nmusini@cisco.com>
Signed-off-by: default avatarSesidhar Baddela <sebaddel@cisco.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent f352a0d5

drivers/scsi/snic/vnic_dev.c

+30 −14
Original line number Diff line number Diff line
@@ -263,12 +263,20 @@ static int _svnic_dev_cmd2(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd, 
	int wait)

{

	struct devcmd2_controller *dc2c = vdev->devcmd2;

	struct devcmd2_result *result = dc2c->result + dc2c->next_result;

	struct devcmd2_result *result = NULL;

	unsigned int i;

	int delay;

	int err;

	u32 posted;

	u32 fetch_idx;

	u32 new_posted;

	u8 color;



	fetch_idx = ioread32(&dc2c->wq_ctrl->fetch_index);

	if (fetch_idx == 0xFFFFFFFF) { /* check for hardware gone  */

		/* Hardware surprise removal: return error */

		return -ENODEV;

	}



	posted = ioread32(&dc2c->wq_ctrl->posted_index);
@@ -278,6 +286,13 @@ static int _svnic_dev_cmd2(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd, 
	}



	new_posted = (posted + 1) % DEVCMD2_RING_SIZE;

	if (new_posted == fetch_idx) {

		pr_err("%s: wq is full while issuing devcmd2 command %d, fetch index: %u, posted index: %u\n",

			pci_name(vdev->pdev), _CMD_N(cmd), fetch_idx, posted);



		return -EBUSY;

	}



	dc2c->cmd_ring[posted].cmd = cmd;

	dc2c->cmd_ring[posted].flags = 0;
@@ -299,14 +314,22 @@ static int _svnic_dev_cmd2(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd, 
	if (dc2c->cmd_ring[posted].flags & DEVCMD2_FNORESULT)

		return 0;



	for (delay = 0; delay < wait; delay++) {

		udelay(100);

		if (result->color == dc2c->color) {

	result = dc2c->result + dc2c->next_result;

	color = dc2c->color;



	/*

	 * Increment next_result, after posting the devcmd, irrespective of

	 * devcmd result, and it should be done only once.

	 */

	dc2c->next_result++;

	if (dc2c->next_result == dc2c->result_size) {

		dc2c->next_result = 0;

		dc2c->color = dc2c->color ? 0 : 1;

	}



	for (delay = 0; delay < wait; delay++) {

		udelay(100);

		if (result->color == color) {

			if (result->error) {

				err = (int) result->error;

				if (err != ERR_ECMDUNKNOWN ||
@@ -317,13 +340,6 @@ static int _svnic_dev_cmd2(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd, 
				return err;

			}

			if (_CMD_DIR(cmd) & _CMD_DIR_READ) {

				/*

				 * Adding the rmb() prevents the compiler

				 * and/or CPU from reordering the reads which

				 * would potentially result in reading stale

				 * values.

				 */

				rmb();

				for (i = 0; i < VNIC_DEVCMD_NARGS; i++)

					vdev->args[i] = result->results[i];

			}