scsi: qla2xxx: Disable ATIO interrupt coalesce for quad port ISP27XX

This partially reverts commit d2b292c ("scsi: qla2xxx: Enable ATIO
interrupt handshake for ISP27XX")

For some workloads where the host sends a batch of commands and then
pauses, ATIO interrupt coalesce can cause some incoming ATIO entries to be
ignored for extended periods of time, resulting in slow performance,
timeouts, and aborted commands.

Disable interrupt coalesce and re-enable the dedicated ATIO MSI-X
interrupt.

Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Himanshu Madhani <[email protected]>
Reviewed-by: Nilesh Javali <[email protected]>
Signed-off-by: Tony Battersby <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: abattersby

drivers/scsi/qla2xxx/qla_target.c

@@ -6935,14 +6935,8 @@ qlt_24xx_config_rings(struct scsi_qla_host *vha)
 
 	if (ha->flags.msix_enabled) {
 		if (IS_QLA83XX(ha) || IS_QLA27XX(ha) || IS_QLA28XX(ha)) {
-			if (IS_QLA2071(ha)) {
-				/* 4 ports Baker: Enable Interrupt Handshake */
-				icb->msix_atio = 0;
-				icb->firmware_options_2 |= cpu_to_le32(BIT_26);
-			} else {
-				icb->msix_atio = cpu_to_le16(msix->entry);
-				icb->firmware_options_2 &= cpu_to_le32(~BIT_26);
-			}
+			icb->msix_atio = cpu_to_le16(msix->entry);
+			icb->firmware_options_2 &= cpu_to_le32(~BIT_26);
 			ql_dbg(ql_dbg_init, vha, 0xf072,
 			    "Registering ICB vector 0x%x for atio que.\n",
 			    msix->entry);