Commit 97e36834 authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk
Browse files

xen/blk[front|back]: Squash blkif_request_rw and blkif_request_discard together 



In a union type structure to deal with the overlapping
attributes in a easier manner.

Suggested-by: default avatarIan Campbell <Ian.Campbell@citrix.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent cfcfc9ec

drivers/block/xen-blkback/blkback.c

+7 −6
Original line number Diff line number Diff line
@@ -362,7 +362,7 @@ static int xen_blkbk_map(struct blkif_request *req, 
{

	struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST];

	int i;

	int nseg = req->nr_segments;

	int nseg = req->u.rw.nr_segments;

	int ret = 0;



	/*
@@ -449,7 +449,7 @@ static void xen_blk_discard(struct xen_blkif *blkif, struct blkif_request *req) 
	} else if (err)

		status = BLKIF_RSP_ERROR;



	make_response(blkif, req->id, req->operation, status);

	make_response(blkif, req->u.discard.id, req->operation, status);

}



static void xen_blk_drain_io(struct xen_blkif *blkif)
@@ -644,7 +644,8 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, 
	}



	/* Check that the number of segments is sane. */

	nseg = req->nr_segments;

	nseg = req->u.rw.nr_segments;



	if (unlikely(nseg == 0 && operation != WRITE_FLUSH &&

				operation != REQ_DISCARD) ||

	    unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
@@ -654,12 +655,12 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, 
		goto fail_response;

	}



	preq.dev           = req->handle;

	preq.dev           = req->u.rw.handle;

	preq.sector_number = req->u.rw.sector_number;

	preq.nr_sects      = 0;



	pending_req->blkif     = blkif;

	pending_req->id        = req->id;

	pending_req->id        = req->u.rw.id;

	pending_req->operation = req->operation;

	pending_req->status    = BLKIF_RSP_OKAY;

	pending_req->nr_pages  = nseg;
@@ -784,7 +785,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif, 
	xen_blkbk_unmap(pending_req);

 fail_response:

	/* Haven't submitted any bio's yet. */

	make_response(blkif, req->id, req->operation, BLKIF_RSP_ERROR);

	make_response(blkif, req->u.rw.id, req->operation, BLKIF_RSP_ERROR);

	free_req(pending_req);

	msleep(1); /* back off a bit */

	return -EIO;

drivers/block/xen-blkback/common.h

+36 −28
Original line number Diff line number Diff line
@@ -60,58 +60,66 @@ struct blkif_common_response { 
	char dummy;

};



/* i386 protocol version */

#pragma pack(push, 4)



struct blkif_x86_32_request_rw {

	uint8_t        nr_segments;  /* number of segments                   */

	blkif_vdev_t   handle;       /* only for read/write requests         */

	uint64_t       id;           /* private guest value, echoed in resp  */

	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */

	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];

};

} __attribute__((__packed__));



struct blkif_x86_32_request_discard {

	uint8_t        nr_segments;  /* number of segments                   */

	blkif_vdev_t   _pad1;        /* was "handle" for read/write requests */

	uint64_t       id;           /* private guest value, echoed in resp  */

	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */

	uint64_t       nr_sectors;

};

} __attribute__((__packed__));



struct blkif_x86_32_request {

	uint8_t        operation;    /* BLKIF_OP_???                         */

	uint8_t        nr_segments;  /* number of segments                   */

	blkif_vdev_t   handle;       /* only for read/write requests         */

	uint64_t       id;           /* private guest value, echoed in resp  */

	union {

		struct blkif_x86_32_request_rw rw;

		struct blkif_x86_32_request_discard discard;

	} u;

};

} __attribute__((__packed__));



/* i386 protocol version */

#pragma pack(push, 4)

struct blkif_x86_32_response {

	uint64_t        id;              /* copied from request */

	uint8_t         operation;       /* copied from request */

	int16_t         status;          /* BLKIF_RSP_???       */

};

#pragma pack(pop)



/* x86_64 protocol version */



struct blkif_x86_64_request_rw {

	uint8_t        nr_segments;  /* number of segments                   */

	blkif_vdev_t   handle;       /* only for read/write requests         */

	uint32_t       _pad1;        /* offsetof(blkif_reqest..,u.rw.id)==8  */

	uint64_t       id;

	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */

	struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];

};

} __attribute__((__packed__));



struct blkif_x86_64_request_discard {

	uint8_t        nr_segments;  /* number of segments                   */

	blkif_vdev_t   _pad1;        /* was "handle" for read/write requests */

        uint32_t       _pad2;        /* offsetof(blkif_..,u.discard.id)==8   */

	uint64_t       id;

	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */

	uint64_t       nr_sectors;

};

} __attribute__((__packed__));



struct blkif_x86_64_request {

	uint8_t        operation;    /* BLKIF_OP_???                         */

	uint8_t        nr_segments;  /* number of segments                   */

	blkif_vdev_t   handle;       /* only for read/write requests         */

	uint64_t       __attribute__((__aligned__(8))) id;

	union {

		struct blkif_x86_64_request_rw rw;

		struct blkif_x86_64_request_discard discard;

	} u;

};

} __attribute__((__packed__));



struct blkif_x86_64_response {

	uint64_t       __attribute__((__aligned__(8))) id;

	uint8_t         operation;       /* copied from request */
@@ -237,18 +245,18 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst, 
{

	int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;

	dst->operation = src->operation;

	dst->nr_segments = src->nr_segments;

	dst->handle = src->handle;

	dst->id = src->id;

	switch (src->operation) {

	case BLKIF_OP_READ:

	case BLKIF_OP_WRITE:

	case BLKIF_OP_WRITE_BARRIER:

	case BLKIF_OP_FLUSH_DISKCACHE:

		dst->u.rw.nr_segments = src->u.rw.nr_segments;

		dst->u.rw.handle = src->u.rw.handle;

		dst->u.rw.id = src->u.rw.id;

		dst->u.rw.sector_number = src->u.rw.sector_number;

		barrier();

		if (n > dst->nr_segments)

			n = dst->nr_segments;

		if (n > dst->u.rw.nr_segments)

			n = dst->u.rw.nr_segments;

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

			dst->u.rw.seg[i] = src->u.rw.seg[i];

		break;
@@ -266,18 +274,18 @@ static inline void blkif_get_x86_64_req(struct blkif_request *dst, 
{

	int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;

	dst->operation = src->operation;

	dst->nr_segments = src->nr_segments;

	dst->handle = src->handle;

	dst->id = src->id;

	switch (src->operation) {

	case BLKIF_OP_READ:

	case BLKIF_OP_WRITE:

	case BLKIF_OP_WRITE_BARRIER:

	case BLKIF_OP_FLUSH_DISKCACHE:

		dst->u.rw.nr_segments = src->u.rw.nr_segments;

		dst->u.rw.handle = src->u.rw.handle;

		dst->u.rw.id = src->u.rw.id;

		dst->u.rw.sector_number = src->u.rw.sector_number;

		barrier();

		if (n > dst->nr_segments)

			n = dst->nr_segments;

		if (n > dst->u.rw.nr_segments)

			n = dst->u.rw.nr_segments;

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

			dst->u.rw.seg[i] = src->u.rw.seg[i];

		break;

drivers/block/xen-blkfront.c

+23 −21
Original line number Diff line number Diff line
@@ -135,15 +135,15 @@ static int get_id_from_freelist(struct blkfront_info *info) 
{

	unsigned long free = info->shadow_free;

	BUG_ON(free >= BLK_RING_SIZE);

	info->shadow_free = info->shadow[free].req.id;

	info->shadow[free].req.id = 0x0fffffee; /* debug */

	info->shadow_free = info->shadow[free].req.u.rw.id;

	info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */

	return free;

}



static void add_id_to_freelist(struct blkfront_info *info,

			       unsigned long id)

{

	info->shadow[id].req.id  = info->shadow_free;

	info->shadow[id].req.u.rw.id  = info->shadow_free;

	info->shadow[id].request = NULL;

	info->shadow_free = id;

}
@@ -287,9 +287,9 @@ static int blkif_queue_request(struct request *req) 
	id = get_id_from_freelist(info);

	info->shadow[id].request = req;



	ring_req->id = id;

	ring_req->u.rw.id = id;

	ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req);

	ring_req->handle = info->handle;

	ring_req->u.rw.handle = info->handle;



	ring_req->operation = rq_data_dir(req) ?

		BLKIF_OP_WRITE : BLKIF_OP_READ;
@@ -308,13 +308,15 @@ static int blkif_queue_request(struct request *req) 
	if (unlikely(req->cmd_flags & REQ_DISCARD)) {

		/* id, sector_number and handle are set above. */

		ring_req->operation = BLKIF_OP_DISCARD;

		ring_req->nr_segments = 0;

		ring_req->u.discard.nr_segments = 0;

		ring_req->u.discard.nr_sectors = blk_rq_sectors(req);

	} else {

		ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);

		BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);

		ring_req->u.rw.nr_segments = blk_rq_map_sg(req->q, req,

							   info->sg);

		BUG_ON(ring_req->u.rw.nr_segments >

		       BLKIF_MAX_SEGMENTS_PER_REQUEST);



		for_each_sg(info->sg, sg, ring_req->nr_segments, i) {

		for_each_sg(info->sg, sg, ring_req->u.rw.nr_segments, i) {

			buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));

			fsect = sg->offset >> 9;

			lsect = fsect + (sg->length >> 9) - 1;
@@ -705,7 +707,7 @@ static void blkif_free(struct blkfront_info *info, int suspend) 
static void blkif_completion(struct blk_shadow *s)

{

	int i;

	for (i = 0; i < s->req.nr_segments; i++)

	for (i = 0; i < s->req.u.rw.nr_segments; i++)

		gnttab_end_foreign_access(s->req.u.rw.seg[i].gref, 0, 0UL);

}
@@ -763,7 +765,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id) 
				error = -EOPNOTSUPP;

			}

			if (unlikely(bret->status == BLKIF_RSP_ERROR &&

				     info->shadow[id].req.nr_segments == 0)) {

				     info->shadow[id].req.u.rw.nr_segments == 0)) {

				printk(KERN_WARNING "blkfront: %s: empty write %s op failed\n",

				       info->flush_op == BLKIF_OP_WRITE_BARRIER ?

				       "barrier" :  "flush disk cache",
@@ -984,8 +986,8 @@ static int blkfront_probe(struct xenbus_device *dev, 
	INIT_WORK(&info->work, blkif_restart_queue);



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

		info->shadow[i].req.id = i+1;

	info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;

		info->shadow[i].req.u.rw.id = i+1;

	info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;



	/* Front end dir is a number, which is used as the id. */

	info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
@@ -1019,9 +1021,9 @@ static int blkif_recover(struct blkfront_info *info) 
	/* Stage 2: Set up free list. */

	memset(&info->shadow, 0, sizeof(info->shadow));

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

		info->shadow[i].req.id = i+1;

		info->shadow[i].req.u.rw.id = i+1;

	info->shadow_free = info->ring.req_prod_pvt;

	info->shadow[BLK_RING_SIZE-1].req.id = 0x0fffffff;

	info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;



	/* Stage 3: Find pending requests and requeue them. */

	for (i = 0; i < BLK_RING_SIZE; i++) {
@@ -1034,17 +1036,17 @@ static int blkif_recover(struct blkfront_info *info) 
		*req = copy[i].req;



		/* We get a new request id, and must reset the shadow state. */

		req->id = get_id_from_freelist(info);

		memcpy(&info->shadow[req->id], &copy[i], sizeof(copy[i]));

		req->u.rw.id = get_id_from_freelist(info);

		memcpy(&info->shadow[req->u.rw.id], &copy[i], sizeof(copy[i]));



		/* Rewrite any grant references invalidated by susp/resume. */

		for (j = 0; j < req->nr_segments; j++)

		for (j = 0; j < req->u.rw.nr_segments; j++)

			gnttab_grant_foreign_access_ref(

				req->u.rw.seg[j].gref,

				info->xbdev->otherend_id,

				pfn_to_mfn(info->shadow[req->id].frame[j]),

				rq_data_dir(info->shadow[req->id].request));

		info->shadow[req->id].req = *req;

				pfn_to_mfn(info->shadow[req->u.rw.id].frame[j]),

				rq_data_dir(info->shadow[req->u.rw.id].request));

		info->shadow[req->u.rw.id].req = *req;



		info->ring.req_prod_pvt++;

	}

include/xen/interface/io/blkif.h

+17 −7
Original line number Diff line number Diff line
@@ -95,6 +95,12 @@ typedef uint64_t blkif_sector_t; 
#define BLKIF_MAX_SEGMENTS_PER_REQUEST 11



struct blkif_request_rw {

	uint8_t        nr_segments;  /* number of segments                   */

	blkif_vdev_t   handle;       /* only for read/write requests         */

#ifdef CONFIG_X86_64

	uint32_t       _pad1;	     /* offsetof(blkif_request,u.rw.id) == 8 */

#endif

	uint64_t       id;           /* private guest value, echoed in resp  */

	blkif_sector_t sector_number;/* start sector idx on disk (r/w only)  */

	struct blkif_request_segment {

		grant_ref_t gref;        /* reference to I/O buffer frame        */
@@ -102,23 +108,27 @@ struct blkif_request_rw { 
		/* @last_sect: last sector in frame to transfer (inclusive).     */

		uint8_t     first_sect, last_sect;

	} seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];

};

} __attribute__((__packed__));



struct blkif_request_discard {

	uint8_t        nr_segments;  /* number of segments                   */

	blkif_vdev_t   _pad1;        /* only for read/write requests         */

#ifdef CONFIG_X86_64

	uint32_t       _pad2;        /* offsetof(blkif_req..,u.discard.id)==8*/

#endif

	uint64_t       id;           /* private guest value, echoed in resp  */

	blkif_sector_t sector_number;

	uint64_t       nr_sectors;

};

	uint8_t        _pad3;

} __attribute__((__packed__));



struct blkif_request {

	uint8_t        operation;    /* BLKIF_OP_???                         */

	uint8_t        nr_segments;  /* number of segments                   */

	blkif_vdev_t   handle;       /* only for read/write requests         */

	uint64_t       id;           /* private guest value, echoed in resp  */

	union {

		struct blkif_request_rw rw;

		struct blkif_request_discard discard;

	} u;

};

} __attribute__((__packed__));



struct blkif_response {

	uint64_t        id;              /* copied from request */