scsi: storvsc: use tagged SRB requests if supported by the device (3cd6d3d9) · Commits · 戴 / test

Properly set SRB flags when hosting device supports tagged queuing. This patch improves the performance on Fiber Channel disks. Signed-off-by:

K. Y. Srinivasan <kys@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by:

drivers/scsi/storvsc_drv.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -136,6 +136,8 @@ struct hv_fc_wwn_packet {
		#define SRB_FLAGS_PORT_DRIVER_RESERVED 0x0F000000
		#define SRB_FLAGS_CLASS_DRIVER_RESERVED 0xF0000000

		#define SP_UNTAGGED ((unsigned char) ~0)
		#define SRB_SIMPLE_TAG_REQUEST 0x20

		/*
		* Platform neutral description of a scsi request -
		@@ -1549,6 +1551,13 @@ static int storvsc_queuecommand(struct Scsi_Host host, struct scsi_cmnd scmnd)
		vm_srb->win8_extension.srb_flags \|=
		SRB_FLAGS_DISABLE_SYNCH_TRANSFER;

		if (scmnd->device->tagged_supported) {
		vm_srb->win8_extension.srb_flags \|=
		(SRB_FLAGS_QUEUE_ACTION_ENABLE \| SRB_FLAGS_NO_QUEUE_FREEZE);
		vm_srb->win8_extension.queue_tag = SP_UNTAGGED;
		vm_srb->win8_extension.queue_action = SRB_SIMPLE_TAG_REQUEST;
		}

		/* Build the SRB */
		switch (scmnd->sc_data_direction) {
		case DMA_TO_DEVICE: