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Commit cb38fa23 authored by Rusty Russell's avatar Rusty Russell
Browse files

virtio: de-structify virtio_block status byte 



Ron Minnich points out that a struct containing a char is not always
sizeof(char); simplest to remove the structure to avoid confusion.

Cc: "ron minnich" <rminnich@gmail.com>

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 81473132

Documentation/lguest/lguest.c

+6 −6
Original line number Diff line number Diff line
@@ -1398,7 +1398,7 @@ static bool service_io(struct device *dev) 
	struct vblk_info *vblk = dev->priv;

	unsigned int head, out_num, in_num, wlen;

	int ret;

	struct virtio_blk_inhdr *in;

	u8 *in;

	struct virtio_blk_outhdr *out;

	struct iovec iov[dev->vq->vring.num];

	off64_t off;
@@ -1416,7 +1416,7 @@ static bool service_io(struct device *dev) 
		     head, out_num, in_num);



	out = convert(&iov[0], struct virtio_blk_outhdr);

	in = convert(&iov[out_num+in_num-1], struct virtio_blk_inhdr);

	in = convert(&iov[out_num+in_num-1], u8);

	off = out->sector * 512;



	/* The block device implements "barriers", where the Guest indicates
@@ -1430,7 +1430,7 @@ static bool service_io(struct device *dev) 
	 * It'd be nice if we supported eject, for example, but we don't. */

	if (out->type & VIRTIO_BLK_T_SCSI_CMD) {

		fprintf(stderr, "Scsi commands unsupported\n");

		in->status = VIRTIO_BLK_S_UNSUPP;

		*in = VIRTIO_BLK_S_UNSUPP;

		wlen = sizeof(*in);

	} else if (out->type & VIRTIO_BLK_T_OUT) {

		/* Write */
@@ -1453,7 +1453,7 @@ static bool service_io(struct device *dev) 
			errx(1, "Write past end %llu+%u", off, ret);

		}

		wlen = sizeof(*in);

		in->status = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);

		*in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);

	} else {

		/* Read */
@@ -1466,10 +1466,10 @@ static bool service_io(struct device *dev) 
		verbose("READ from sector %llu: %i\n", out->sector, ret);

		if (ret >= 0) {

			wlen = sizeof(*in) + ret;

			in->status = VIRTIO_BLK_S_OK;

			*in = VIRTIO_BLK_S_OK;

		} else {

			wlen = sizeof(*in);

			in->status = VIRTIO_BLK_S_IOERR;

			*in = VIRTIO_BLK_S_IOERR;

		}

	}

drivers/block/virtio_blk.c

+3 −3
Original line number Diff line number Diff line
@@ -35,7 +35,7 @@ struct virtblk_req 
	struct list_head list;

	struct request *req;

	struct virtio_blk_outhdr out_hdr;

	struct virtio_blk_inhdr in_hdr;

	u8 status;

};



static void blk_done(struct virtqueue *vq)
@@ -48,7 +48,7 @@ static void blk_done(struct virtqueue *vq) 
	spin_lock_irqsave(&vblk->lock, flags);

	while ((vbr = vblk->vq->vq_ops->get_buf(vblk->vq, &len)) != NULL) {

		int uptodate;

		switch (vbr->in_hdr.status) {

		switch (vbr->status) {

		case VIRTIO_BLK_S_OK:

			uptodate = 1;

			break;
@@ -101,7 +101,7 @@ static bool do_req(struct request_queue *q, struct virtio_blk *vblk, 
	sg_init_table(vblk->sg, VIRTIO_MAX_SG);

	sg_set_buf(&vblk->sg[0], &vbr->out_hdr, sizeof(vbr->out_hdr));

	num = blk_rq_map_sg(q, vbr->req, vblk->sg+1);

	sg_set_buf(&vblk->sg[num+1], &vbr->in_hdr, sizeof(vbr->in_hdr));

	sg_set_buf(&vblk->sg[num+1], &vbr->status, sizeof(vbr->status));



	if (rq_data_dir(vbr->req) == WRITE) {

		vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;

include/linux/virtio_blk.h

+1 −6
Original line number Diff line number Diff line
@@ -41,13 +41,8 @@ struct virtio_blk_outhdr 
	__u64 sector;

};



/* And this is the final byte of the write scatter-gather list. */

#define VIRTIO_BLK_S_OK		0

#define VIRTIO_BLK_S_IOERR	1

#define VIRTIO_BLK_S_UNSUPP	2



/* This is the first element of the write scatter-gather list */

struct virtio_blk_inhdr

{

	unsigned char status;

};

#endif /* _LINUX_VIRTIO_BLK_H */