virtio_blk: add support for cache flush (f1b0ef06) · Commits · 戴 / test

drivers/block/virtio_blk.c

+25 −5

Original line number	Diff line number	Diff line
		@@ -92,15 +92,26 @@ static bool do_req(struct request_queue q, struct virtio_blk vblk,
		return false;

		vbr->req = req;
		if (blk_fs_request(vbr->req)) {
		switch (req->cmd_type) {
		case REQ_TYPE_FS:
		vbr->out_hdr.type = 0;
		vbr->out_hdr.sector = blk_rq_pos(vbr->req);
		vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
		} else if (blk_pc_request(vbr->req)) {
		break;
		case REQ_TYPE_BLOCK_PC:
		vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
		vbr->out_hdr.sector = 0;
		vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
		} else {
		break;
		case REQ_TYPE_LINUX_BLOCK:
		if (req->cmd[0] == REQ_LB_OP_FLUSH) {
		vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH;
		vbr->out_hdr.sector = 0;
		vbr->out_hdr.ioprio = req_get_ioprio(vbr->req);
		break;
		}
		/FALLTHRU/
		default:
		/* We don't put anything else in the queue. */
		BUG();
		}
		@@ -200,6 +211,12 @@ out:
		return err;
		}

		static void virtblk_prepare_flush(struct request_queue q, struct request req)
		{
		req->cmd_type = REQ_TYPE_LINUX_BLOCK;
		req->cmd[0] = REQ_LB_OP_FLUSH;
		}

		static int virtblk_ioctl(struct block_device *bdev, fmode_t mode,
		unsigned cmd, unsigned long data)
		{
		@@ -338,7 +355,10 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
		index++;

		/* If barriers are supported, tell block layer that queue is ordered */
		if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))
		if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
		blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_DRAIN_FLUSH,
		virtblk_prepare_flush);
		else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER))
		blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);

		/* If disk is read-only in the host, the guest should obey */
		@@ -425,7 +445,7 @@ static struct virtio_device_id id_table[] = {
		static unsigned int features[] = {
		VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX,
		VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
		VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_IDENTIFY
		VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_IDENTIFY, VIRTIO_BLK_F_FLUSH
		};

		/*

include/linux/virtio_blk.h

+15 −0

Original line number	Diff line number	Diff line
		@@ -14,6 +14,7 @@
		#define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/
		#define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
		#define VIRTIO_BLK_F_IDENTIFY 8 /* ATA IDENTIFY supported */
		#define VIRTIO_BLK_F_FLUSH 9 /* Cache flush command support */

		#define VIRTIO_BLK_ID_BYTES (sizeof(__u16[256])) /* IDENTIFY DATA */

		@@ -35,6 +36,17 @@ struct virtio_blk_config {
		__u8 identify[VIRTIO_BLK_ID_BYTES];
		} __attribute__((packed));

		/*
		* Command types
		*
		* Usage is a bit tricky as some bits are used as flags and some are not.
		*
		* Rules:
		* VIRTIO_BLK_T_OUT may be combined with VIRTIO_BLK_T_SCSI_CMD or
		* VIRTIO_BLK_T_BARRIER. VIRTIO_BLK_T_FLUSH is a command of its own
		* and may not be combined with any of the other flags.
		*/

		/* These two define direction. */
		#define VIRTIO_BLK_T_IN 0
		#define VIRTIO_BLK_T_OUT 1
		@@ -42,6 +54,9 @@ struct virtio_blk_config {
		/* This bit says it's a scsi command, not an actual read or write. */
		#define VIRTIO_BLK_T_SCSI_CMD 2

		/* Cache flush command */
		#define VIRTIO_BLK_T_FLUSH 4

		/* Barrier before this op. */
		#define VIRTIO_BLK_T_BARRIER 0x80000000

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