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Merge branch 'stable/for-jens-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-3.3/drivers

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This commit is contained in:
Jens Axboe 2011-12-25 16:46:46 +01:00
commit f748040bb8
5 changed files with 175 additions and 117 deletions
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70
drivers/block/xen-blkback/blkback.c
View File

@ -39,9 +39,6 @@
#include <linux/list.h>
#include <linux/delay.h>
#include <linux/freezer.h>
#include <linux/loop.h>
#include <linux/falloc.h>
#include <linux/fs.h>
#include <xen/events.h>
#include <xen/page.h>
@ -362,7 +359,7 @@ 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;
/*
@ -416,30 +413,25 @@ static int xen_blkbk_map(struct blkif_request *req,
return ret;
}
static void xen_blk_discard(struct xen_blkif *blkif, struct blkif_request *req)
static int dispatch_discard_io(struct xen_blkif *blkif,
struct blkif_request *req)
{
int err = 0;
int status = BLKIF_RSP_OKAY;
struct block_device *bdev = blkif->vbd.bdev;
if (blkif->blk_backend_type == BLKIF_BACKEND_PHY)
/* just forward the discard request */
blkif->st_ds_req++;
xen_blkif_get(blkif);
if (blkif->blk_backend_type == BLKIF_BACKEND_PHY ||
blkif->blk_backend_type == BLKIF_BACKEND_FILE) {
unsigned long secure = (blkif->vbd.discard_secure &&
(req->u.discard.flag & BLKIF_DISCARD_SECURE)) ?
BLKDEV_DISCARD_SECURE : 0;
err = blkdev_issue_discard(bdev,
req->u.discard.sector_number,
req->u.discard.nr_sectors,
GFP_KERNEL, 0);
else if (blkif->blk_backend_type == BLKIF_BACKEND_FILE) {
/* punch a hole in the backing file */
struct loop_device *lo = bdev->bd_disk->private_data;
struct file *file = lo->lo_backing_file;
if (file->f_op->fallocate)
err = file->f_op->fallocate(file,
FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
req->u.discard.sector_number << 9,
req->u.discard.nr_sectors << 9);
else
err = -EOPNOTSUPP;
GFP_KERNEL, secure);
} else
err = -EOPNOTSUPP;
@ -449,7 +441,9 @@ 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);
xen_blkif_put(blkif);
return err;
}
static void xen_blk_drain_io(struct xen_blkif *blkif)
@ -573,8 +567,11 @@ __do_block_io_op(struct xen_blkif *blkif)
/* Apply all sanity checks to /private copy/ of request. */
barrier();
if (dispatch_rw_block_io(blkif, &req, pending_req))
if (unlikely(req.operation == BLKIF_OP_DISCARD)) {
free_req(pending_req);
if (dispatch_discard_io(blkif, &req))
break;
} else if (dispatch_rw_block_io(blkif, &req, pending_req))
break;
/* Yield point for this unbounded loop. */
@ -633,10 +630,6 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
blkif->st_f_req++;
operation = WRITE_FLUSH;
break;
case BLKIF_OP_DISCARD:
blkif->st_ds_req++;
operation = REQ_DISCARD;
break;
default:
operation = 0; /* make gcc happy */
goto fail_response;
@ -644,9 +637,9 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
}
/* Check that the number of segments is sane. */
nseg = req->nr_segments;
if (unlikely(nseg == 0 && operation != WRITE_FLUSH &&
operation != REQ_DISCARD) ||
nseg = req->u.rw.nr_segments;
if (unlikely(nseg == 0 && operation != WRITE_FLUSH) ||
unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
pr_debug(DRV_PFX "Bad number of segments in request (%d)\n",
nseg);
@ -654,12 +647,12 @@ 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;
@ -707,7 +700,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
* the hypercall to unmap the grants - that is all done in
* xen_blkbk_unmap.
*/
if (operation != REQ_DISCARD && xen_blkbk_map(req, pending_req, seg))
if (xen_blkbk_map(req, pending_req, seg))
goto fail_flush;
/*
@ -739,9 +732,8 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
/* This will be hit if the operation was a flush or discard. */
if (!bio) {
BUG_ON(operation != WRITE_FLUSH && operation != REQ_DISCARD);
BUG_ON(operation != WRITE_FLUSH);
if (operation == WRITE_FLUSH) {
bio = bio_alloc(GFP_KERNEL, 0);
if (unlikely(bio == NULL))
goto fail_put_bio;
@ -750,12 +742,6 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
bio->bi_bdev = preq.bdev;
bio->bi_private = pending_req;
bio->bi_end_io = end_block_io_op;
} else if (operation == REQ_DISCARD) {
xen_blk_discard(blkif, req);
xen_blkif_put(blkif);
free_req(pending_req);
return 0;
}
}
/*
@ -784,7 +770,7 @@ 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;

75
drivers/block/xen-blkback/common.h
View File

@ -60,58 +60,66 @@ struct blkif_common_response {
char dummy;
};
/* i386 protocol version */
#pragma pack(push, 4)
struct blkif_x86_32_request_rw {
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};
struct blkif_x86_32_request_discard {
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
uint64_t nr_sectors;
};
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 */
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 flag; /* BLKIF_DISCARD_SECURE or zero */
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_??? */
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 flag; /* BLKIF_DISCARD_SECURE or zero */
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 */
@ -156,6 +164,7 @@ struct xen_vbd {
/* Cached size parameter. */
sector_t size;
bool flush_support;
bool discard_secure;
};
struct backend_info;
@ -237,22 +246,23 @@ 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;
case BLKIF_OP_DISCARD:
dst->u.discard.flag = src->u.discard.flag;
dst->u.discard.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;
@ -266,22 +276,23 @@ 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;
case BLKIF_OP_DISCARD:
dst->u.discard.flag = src->u.discard.flag;
dst->u.discard.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;

12
drivers/block/xen-blkback/xenbus.c
View File

@ -338,6 +338,9 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
if (q && q->flush_flags)
vbd->flush_support = true;
if (q && blk_queue_secdiscard(q))
vbd->discard_secure = true;
DPRINTK("Successful creation of handle=%04x (dom=%u)\n",
handle, blkif->domid);
return 0;
@ -420,6 +423,15 @@ int xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be)
state = 1;
blkif->blk_backend_type = BLKIF_BACKEND_PHY;
}
/* Optional. */
err = xenbus_printf(xbt, dev->nodename,
"discard-secure", "%d",
blkif->vbd.discard_secure);
if (err) {
xenbus_dev_fatal(dev, err,
"writting discard-secure");
goto kfree;
}
}
} else {
err = PTR_ERR(type);

71
drivers/block/xen-blkfront.c
View File

@ -98,7 +98,8 @@ struct blkfront_info
unsigned long shadow_free;
unsigned int feature_flush;
unsigned int flush_op;
unsigned int feature_discard;
unsigned int feature_discard:1;
unsigned int feature_secdiscard:1;
unsigned int discard_granularity;
unsigned int discard_alignment;
int is_ready;
@ -135,15 +136,15 @@ 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;
}
@ -156,7 +157,7 @@ static int xlbd_reserve_minors(unsigned int minor, unsigned int nr)
if (end > nr_minors) {
unsigned long *bitmap, *old;
bitmap = kzalloc(BITS_TO_LONGS(end) * sizeof(*bitmap),
bitmap = kcalloc(BITS_TO_LONGS(end), sizeof(*bitmap),
GFP_KERNEL);
if (bitmap == NULL)
return -ENOMEM;
@ -287,9 +288,9 @@ 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;
@ -305,16 +306,21 @@ static int blkif_queue_request(struct request *req)
ring_req->operation = info->flush_op;
}
if (unlikely(req->cmd_flags & REQ_DISCARD)) {
if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE))) {
/* id, sector_number and handle are set above. */
ring_req->operation = BLKIF_OP_DISCARD;
ring_req->nr_segments = 0;
ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)
ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;
else
ring_req->u.discard.flag = 0;
} 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;
@ -424,6 +430,8 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
blk_queue_max_discard_sectors(rq, get_capacity(gd));
rq->limits.discard_granularity = info->discard_granularity;
rq->limits.discard_alignment = info->discard_alignment;
if (info->feature_secdiscard)
queue_flag_set_unlocked(QUEUE_FLAG_SECDISCARD, rq);
}
/* Hard sector size and max sectors impersonate the equiv. hardware. */
@ -705,7 +713,9 @@ 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++)
/* Do not let BLKIF_OP_DISCARD as nr_segment is in the same place
* flag. */
for (i = 0; i < s->req.u.rw.nr_segments; i++)
gnttab_end_foreign_access(s->req.u.rw.seg[i].gref, 0, 0UL);
}
@ -736,6 +746,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
id = bret->id;
req = info->shadow[id].request;
if (bret->operation != BLKIF_OP_DISCARD)
blkif_completion(&info->shadow[id]);
add_id_to_freelist(info, id);
@ -749,7 +760,9 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
info->gd->disk_name);
error = -EOPNOTSUPP;
info->feature_discard = 0;
info->feature_secdiscard = 0;
queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
}
__blk_end_request_all(req, error);
break;
@ -763,7 +776,7 @@ 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 +997,8 @@ 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 +1032,9 @@ 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 +1047,19 @@ 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]));
if (req->operation != BLKIF_OP_DISCARD) {
/* 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++;
}
@ -1135,11 +1150,13 @@ static void blkfront_setup_discard(struct blkfront_info *info)
char *type;
unsigned int discard_granularity;
unsigned int discard_alignment;
unsigned int discard_secure;
type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
if (IS_ERR(type))
return;
info->feature_secdiscard = 0;
if (strncmp(type, "phy", 3) == 0) {
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
"discard-granularity", "%u", &discard_granularity,
@ -1150,6 +1167,12 @@ static void blkfront_setup_discard(struct blkfront_info *info)
info->discard_granularity = discard_granularity;
info->discard_alignment = discard_alignment;
}
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
"discard-secure", "%d", &discard_secure,
NULL);
if (!err)
info->feature_secdiscard = discard_secure;
} else if (strncmp(type, "file", 4) == 0)
info->feature_discard = 1;

38
include/xen/interface/io/blkif.h
View File

@ -84,6 +84,21 @@ typedef uint64_t blkif_sector_t;
* e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
* http://www.seagate.com/staticfiles/support/disc/manuals/
* Interface%20manuals/100293068c.pdf
* The backend can optionally provide three extra XenBus attributes to
* further optimize the discard functionality:
* 'discard-aligment' - Devices that support discard functionality may
* internally allocate space in units that are bigger than the exported
* logical block size. The discard-alignment parameter indicates how many bytes
* the beginning of the partition is offset from the internal allocation unit's
* natural alignment.
* 'discard-granularity' - Devices that support discard functionality may
* internally allocate space using units that are bigger than the logical block
* size. The discard-granularity parameter indicates the size of the internal
* allocation unit in bytes if reported by the device. Otherwise the
* discard-granularity will be set to match the device's physical block size.
* 'discard-secure' - All copies of the discarded sectors (potentially created
* by garbage collection) must also be erased. To use this feature, the flag
* BLKIF_DISCARD_SECURE must be set in the blkif_request_trim.
*/
#define BLKIF_OP_DISCARD 5
@ -95,6 +110,12 @@ 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 +123,28 @@ 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 flag; /* BLKIF_DISCARD_SECURE or zero. */
#define BLKIF_DISCARD_SECURE (1<<0) /* ignored if discard-secure=0 */
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 */