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Merge branch 'stable/for-jens-3.2' of git://oss.oracle.com/git/kwilk/xen into for-3.2/drivers

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This commit is contained in:
Jens Axboe 2011-10-20 15:10:59 +02:00
commit b8d8bdfe31
5 changed files with 402 additions and 65 deletions
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130
drivers/block/xen-blkback/blkback.c
View file

@ -39,6 +39,9 @@
#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>
@ -258,13 +261,16 @@ irqreturn_t xen_blkif_be_int(int irq, void *dev_id)
static void print_stats(struct xen_blkif *blkif)
{
pr_info("xen-blkback (%s): oo %3d | rd %4d | wr %4d | f %4d\n",
pr_info("xen-blkback (%s): oo %3d | rd %4d | wr %4d | f %4d"
" | ds %4d\n",
current->comm, blkif->st_oo_req,
blkif->st_rd_req, blkif->st_wr_req, blkif->st_f_req);
blkif->st_rd_req, blkif->st_wr_req,
blkif->st_f_req, blkif->st_ds_req);
blkif->st_print = jiffies + msecs_to_jiffies(10 * 1000);
blkif->st_rd_req = 0;
blkif->st_wr_req = 0;
blkif->st_oo_req = 0;
blkif->st_ds_req = 0;
}
int xen_blkif_schedule(void *arg)
@ -410,6 +416,59 @@ static int xen_blkbk_map(struct blkif_request *req,
return ret;
}
static void xen_blk_discard(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 */
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;
} else
err = -EOPNOTSUPP;
if (err == -EOPNOTSUPP) {
pr_debug(DRV_PFX "discard op failed, not supported\n");
status = BLKIF_RSP_EOPNOTSUPP;
} else if (err)
status = BLKIF_RSP_ERROR;
make_response(blkif, req->id, req->operation, status);
}
static void xen_blk_drain_io(struct xen_blkif *blkif)
{
atomic_set(&blkif->drain, 1);
do {
/* The initial value is one, and one refcnt taken at the
* start of the xen_blkif_schedule thread. */
if (atomic_read(&blkif->refcnt) <= 2)
break;
wait_for_completion_interruptible_timeout(
&blkif->drain_complete, HZ);
if (!atomic_read(&blkif->drain))
break;
} while (!kthread_should_stop());
atomic_set(&blkif->drain, 0);
}
/*
* Completion callback on the bio's. Called as bh->b_end_io()
*/
@ -422,6 +481,11 @@ static void __end_block_io_op(struct pending_req *pending_req, int error)
pr_debug(DRV_PFX "flush diskcache op failed, not supported\n");
xen_blkbk_flush_diskcache(XBT_NIL, pending_req->blkif->be, 0);
pending_req->status = BLKIF_RSP_EOPNOTSUPP;
} else if ((pending_req->operation == BLKIF_OP_WRITE_BARRIER) &&
(error == -EOPNOTSUPP)) {
pr_debug(DRV_PFX "write barrier op failed, not supported\n");
xen_blkbk_barrier(XBT_NIL, pending_req->blkif->be, 0);
pending_req->status = BLKIF_RSP_EOPNOTSUPP;
} else if (error) {
pr_debug(DRV_PFX "Buffer not up-to-date at end of operation,"
" error=%d\n", error);
@ -438,6 +502,10 @@ static void __end_block_io_op(struct pending_req *pending_req, int error)
make_response(pending_req->blkif, pending_req->id,
pending_req->operation, pending_req->status);
xen_blkif_put(pending_req->blkif);
if (atomic_read(&pending_req->blkif->refcnt) <= 2) {
if (atomic_read(&pending_req->blkif->drain))
complete(&pending_req->blkif->drain_complete);
}
free_req(pending_req);
}
}
@ -532,7 +600,6 @@ do_block_io_op(struct xen_blkif *blkif)
return more_to_do;
}
/*
* Transmutation of the 'struct blkif_request' to a proper 'struct bio'
* and call the 'submit_bio' to pass it to the underlying storage.
@ -549,6 +616,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
int i, nbio = 0;
int operation;
struct blk_plug plug;
bool drain = false;
switch (req->operation) {
case BLKIF_OP_READ:
@ -559,11 +627,16 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
blkif->st_wr_req++;
operation = WRITE_ODIRECT;
break;
case BLKIF_OP_WRITE_BARRIER:
drain = true;
case BLKIF_OP_FLUSH_DISKCACHE:
blkif->st_f_req++;
operation = WRITE_FLUSH;
break;
case BLKIF_OP_WRITE_BARRIER:
case BLKIF_OP_DISCARD:
blkif->st_ds_req++;
operation = REQ_DISCARD;
break;
default:
operation = 0; /* make gcc happy */
goto fail_response;
@ -572,7 +645,8 @@ 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) ||
if (unlikely(nseg == 0 && operation != WRITE_FLUSH &&
operation != REQ_DISCARD) ||
unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
pr_debug(DRV_PFX "Bad number of segments in request (%d)\n",
nseg);
@ -621,16 +695,25 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
}
}
/* Wait on all outstanding I/O's and once that has been completed
* issue the WRITE_FLUSH.
*/
if (drain)
xen_blk_drain_io(pending_req->blkif);
/*
* If we have failed at this point, we need to undo the M2P override,
* set gnttab_set_unmap_op on all of the grant references and perform
* the hypercall to unmap the grants - that is all done in
* xen_blkbk_unmap.
*/
if (xen_blkbk_map(req, pending_req, seg))
if (operation != REQ_DISCARD && xen_blkbk_map(req, pending_req, seg))
goto fail_flush;
/* This corresponding xen_blkif_put is done in __end_block_io_op */
/*
* This corresponding xen_blkif_put is done in __end_block_io_op, or
* below (in "!bio") if we are handling a BLKIF_OP_DISCARD.
*/
xen_blkif_get(blkif);
for (i = 0; i < nseg; i++) {
@ -654,18 +737,25 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
preq.sector_number += seg[i].nsec;
}
/* This will be hit if the operation was a flush. */
/* This will be hit if the operation was a flush or discard. */
if (!bio) {
BUG_ON(operation != WRITE_FLUSH);
BUG_ON(operation != WRITE_FLUSH && operation != REQ_DISCARD);
bio = bio_alloc(GFP_KERNEL, 0);
if (unlikely(bio == NULL))
goto fail_put_bio;
if (operation == WRITE_FLUSH) {
bio = bio_alloc(GFP_KERNEL, 0);
if (unlikely(bio == NULL))
goto fail_put_bio;
biolist[nbio++] = bio;
bio->bi_bdev = preq.bdev;
bio->bi_private = pending_req;
bio->bi_end_io = end_block_io_op;
biolist[nbio++] = bio;
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;
}
}
/*
@ -685,7 +775,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
if (operation == READ)
blkif->st_rd_sect += preq.nr_sects;
else if (operation == WRITE || operation == WRITE_FLUSH)
else if (operation & WRITE)
blkif->st_wr_sect += preq.nr_sects;
return 0;
@ -765,9 +855,9 @@ static int __init xen_blkif_init(void)
mmap_pages = xen_blkif_reqs * BLKIF_MAX_SEGMENTS_PER_REQUEST;
blkbk->pending_reqs = kmalloc(sizeof(blkbk->pending_reqs[0]) *
blkbk->pending_reqs = kzalloc(sizeof(blkbk->pending_reqs[0]) *
xen_blkif_reqs, GFP_KERNEL);
blkbk->pending_grant_handles = kzalloc(sizeof(blkbk->pending_grant_handles[0]) *
blkbk->pending_grant_handles = kmalloc(sizeof(blkbk->pending_grant_handles[0]) *
mmap_pages, GFP_KERNEL);
blkbk->pending_pages = kzalloc(sizeof(blkbk->pending_pages[0]) *
mmap_pages, GFP_KERNEL);
@ -790,8 +880,6 @@ static int __init xen_blkif_init(void)
if (rc)
goto failed_init;
memset(blkbk->pending_reqs, 0, sizeof(blkbk->pending_reqs));
INIT_LIST_HEAD(&blkbk->pending_free);
spin_lock_init(&blkbk->pending_free_lock);
init_waitqueue_head(&blkbk->pending_free_wq);

100
drivers/block/xen-blkback/common.h
View file

@ -46,7 +46,7 @@
#define DRV_PFX "xen-blkback:"
#define DPRINTK(fmt, args...) \
pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \
pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \
__func__, __LINE__, ##args)
@ -63,13 +63,26 @@ struct blkif_common_response {
/* 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];
union {
struct blkif_x86_32_request_rw rw;
struct blkif_x86_32_request_discard discard;
} u;
};
struct blkif_x86_32_response {
uint64_t id; /* copied from request */
@ -79,13 +92,26 @@ struct blkif_x86_32_response {
#pragma pack(pop)
/* x86_64 protocol version */
struct blkif_x86_64_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_64_request_discard {
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
uint64_t nr_sectors;
};
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;
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
union {
struct blkif_x86_64_request_rw rw;
struct blkif_x86_64_request_discard discard;
} u;
};
struct blkif_x86_64_response {
uint64_t __attribute__((__aligned__(8))) id;
@ -113,6 +139,11 @@ enum blkif_protocol {
BLKIF_PROTOCOL_X86_64 = 3,
};
enum blkif_backend_type {
BLKIF_BACKEND_PHY = 1,
BLKIF_BACKEND_FILE = 2,
};
struct xen_vbd {
/* What the domain refers to this vbd as. */
blkif_vdev_t handle;
@ -138,6 +169,7 @@ struct xen_blkif {
unsigned int irq;
/* Comms information. */
enum blkif_protocol blk_protocol;
enum blkif_backend_type blk_backend_type;
union blkif_back_rings blk_rings;
struct vm_struct *blk_ring_area;
/* The VBD attached to this interface. */
@ -149,6 +181,9 @@ struct xen_blkif {
atomic_t refcnt;
wait_queue_head_t wq;
/* for barrier (drain) requests */
struct completion drain_complete;
atomic_t drain;
/* One thread per one blkif. */
struct task_struct *xenblkd;
unsigned int waiting_reqs;
@ -159,6 +194,7 @@ struct xen_blkif {
int st_wr_req;
int st_oo_req;
int st_f_req;
int st_ds_req;
int st_rd_sect;
int st_wr_sect;
@ -182,7 +218,7 @@ struct xen_blkif {
struct phys_req {
unsigned short dev;
unsigned short nr_sects;
blkif_sector_t nr_sects;
struct block_device *bdev;
blkif_sector_t sector_number;
};
@ -196,6 +232,8 @@ int xen_blkif_schedule(void *arg);
int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
struct backend_info *be, int state);
int xen_blkbk_barrier(struct xenbus_transaction xbt,
struct backend_info *be, int state);
struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
static inline void blkif_get_x86_32_req(struct blkif_request *dst,
@ -206,12 +244,25 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst,
dst->nr_segments = src->nr_segments;
dst->handle = src->handle;
dst->id = src->id;
dst->u.rw.sector_number = src->sector_number;
barrier();
if (n > dst->nr_segments)
n = dst->nr_segments;
for (i = 0; i < n; i++)
dst->u.rw.seg[i] = src->seg[i];
switch (src->operation) {
case BLKIF_OP_READ:
case BLKIF_OP_WRITE:
case BLKIF_OP_WRITE_BARRIER:
case BLKIF_OP_FLUSH_DISKCACHE:
dst->u.rw.sector_number = src->u.rw.sector_number;
barrier();
if (n > dst->nr_segments)
n = dst->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.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;
default:
break;
}
}
static inline void blkif_get_x86_64_req(struct blkif_request *dst,
@ -222,12 +273,25 @@ static inline void blkif_get_x86_64_req(struct blkif_request *dst,
dst->nr_segments = src->nr_segments;
dst->handle = src->handle;
dst->id = src->id;
dst->u.rw.sector_number = src->sector_number;
barrier();
if (n > dst->nr_segments)
n = dst->nr_segments;
for (i = 0; i < n; i++)
dst->u.rw.seg[i] = src->seg[i];
switch (src->operation) {
case BLKIF_OP_READ:
case BLKIF_OP_WRITE:
case BLKIF_OP_WRITE_BARRIER:
case BLKIF_OP_FLUSH_DISKCACHE:
dst->u.rw.sector_number = src->u.rw.sector_number;
barrier();
if (n > dst->nr_segments)
n = dst->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.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;
default:
break;
}
}
#endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */

80
drivers/block/xen-blkback/xenbus.c
View file

@ -114,6 +114,8 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
spin_lock_init(&blkif->blk_ring_lock);
atomic_set(&blkif->refcnt, 1);
init_waitqueue_head(&blkif->wq);
init_completion(&blkif->drain_complete);
atomic_set(&blkif->drain, 0);
blkif->st_print = jiffies;
init_waitqueue_head(&blkif->waiting_to_free);
@ -272,6 +274,7 @@ VBD_SHOW(oo_req, "%d\n", be->blkif->st_oo_req);
VBD_SHOW(rd_req, "%d\n", be->blkif->st_rd_req);
VBD_SHOW(wr_req, "%d\n", be->blkif->st_wr_req);
VBD_SHOW(f_req, "%d\n", be->blkif->st_f_req);
VBD_SHOW(ds_req, "%d\n", be->blkif->st_ds_req);
VBD_SHOW(rd_sect, "%d\n", be->blkif->st_rd_sect);
VBD_SHOW(wr_sect, "%d\n", be->blkif->st_wr_sect);
@ -280,6 +283,7 @@ static struct attribute *xen_vbdstat_attrs[] = {
&dev_attr_rd_req.attr,
&dev_attr_wr_req.attr,
&dev_attr_f_req.attr,
&dev_attr_ds_req.attr,
&dev_attr_rd_sect.attr,
&dev_attr_wr_sect.attr,
NULL
@ -419,6 +423,73 @@ int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
return err;
}
int xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be)
{
struct xenbus_device *dev = be->dev;
struct xen_blkif *blkif = be->blkif;
char *type;
int err;
int state = 0;
type = xenbus_read(XBT_NIL, dev->nodename, "type", NULL);
if (!IS_ERR(type)) {
if (strncmp(type, "file", 4) == 0) {
state = 1;
blkif->blk_backend_type = BLKIF_BACKEND_FILE;
}
if (strncmp(type, "phy", 3) == 0) {
struct block_device *bdev = be->blkif->vbd.bdev;
struct request_queue *q = bdev_get_queue(bdev);
if (blk_queue_discard(q)) {
err = xenbus_printf(xbt, dev->nodename,
"discard-granularity", "%u",
q->limits.discard_granularity);
if (err) {
xenbus_dev_fatal(dev, err,
"writing discard-granularity");
goto kfree;
}
err = xenbus_printf(xbt, dev->nodename,
"discard-alignment", "%u",
q->limits.discard_alignment);
if (err) {
xenbus_dev_fatal(dev, err,
"writing discard-alignment");
goto kfree;
}
state = 1;
blkif->blk_backend_type = BLKIF_BACKEND_PHY;
}
}
} else {
err = PTR_ERR(type);
xenbus_dev_fatal(dev, err, "reading type");
goto out;
}
err = xenbus_printf(xbt, dev->nodename, "feature-discard",
"%d", state);
if (err)
xenbus_dev_fatal(dev, err, "writing feature-discard");
kfree:
kfree(type);
out:
return err;
}
int xen_blkbk_barrier(struct xenbus_transaction xbt,
struct backend_info *be, int state)
{
struct xenbus_device *dev = be->dev;
int err;
err = xenbus_printf(xbt, dev->nodename, "feature-barrier",
"%d", state);
if (err)
xenbus_dev_fatal(dev, err, "writing feature-barrier");
return err;
}
/*
* Entry point to this code when a new device is created. Allocate the basic
* structures, and watch the store waiting for the hotplug scripts to tell us
@ -590,7 +661,7 @@ static void frontend_changed(struct xenbus_device *dev,
/*
* Enforce precondition before potential leak point.
* blkif_disconnect() is idempotent.
* xen_blkif_disconnect() is idempotent.
*/
xen_blkif_disconnect(be->blkif);
@ -611,7 +682,7 @@ static void frontend_changed(struct xenbus_device *dev,
break;
/* fall through if not online */
case XenbusStateUnknown:
/* implies blkif_disconnect() via blkback_remove() */
/* implies xen_blkif_disconnect() via xen_blkbk_remove() */
device_unregister(&dev->dev);
break;
@ -650,6 +721,11 @@ static void connect(struct backend_info *be)
if (err)
goto abort;
err = xen_blkbk_discard(xbt, be);
/* If we can't advertise it is OK. */
err = xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
(unsigned long long)vbd_sz(&be->blkif->vbd));
if (err) {

121
drivers/block/xen-blkfront.c
View file

@ -98,6 +98,9 @@ struct blkfront_info
unsigned long shadow_free;
unsigned int feature_flush;
unsigned int flush_op;
unsigned int feature_discard;
unsigned int discard_granularity;
unsigned int discard_alignment;
int is_ready;
};
@ -302,29 +305,36 @@ static int blkif_queue_request(struct request *req)
ring_req->operation = info->flush_op;
}
ring_req->nr_segments = blk_rq_map_sg(req->q, req, info->sg);
BUG_ON(ring_req->nr_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
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_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);
for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
fsect = sg->offset >> 9;
lsect = fsect + (sg->length >> 9) - 1;
/* install a grant reference. */
ref = gnttab_claim_grant_reference(&gref_head);
BUG_ON(ref == -ENOSPC);
for_each_sg(info->sg, sg, ring_req->nr_segments, i) {
buffer_mfn = pfn_to_mfn(page_to_pfn(sg_page(sg)));
fsect = sg->offset >> 9;
lsect = fsect + (sg->length >> 9) - 1;
/* install a grant reference. */
ref = gnttab_claim_grant_reference(&gref_head);
BUG_ON(ref == -ENOSPC);
gnttab_grant_foreign_access_ref(
ref,
info->xbdev->otherend_id,
buffer_mfn,
rq_data_dir(req) );
gnttab_grant_foreign_access_ref(
ref,
info->xbdev->otherend_id,
buffer_mfn,
rq_data_dir(req));
info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
ring_req->u.rw.seg[i] =
(struct blkif_request_segment) {
.gref = ref,
.first_sect = fsect,
.last_sect = lsect };
info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
ring_req->u.rw.seg[i] =
(struct blkif_request_segment) {
.gref = ref,
.first_sect = fsect,
.last_sect = lsect };
}
}
info->ring.req_prod_pvt++;
@ -370,7 +380,9 @@ static void do_blkif_request(struct request_queue *rq)
blk_start_request(req);
if (req->cmd_type != REQ_TYPE_FS) {
if ((req->cmd_type != REQ_TYPE_FS) ||
((req->cmd_flags & (REQ_FLUSH | REQ_FUA)) &&
!info->flush_op)) {
__blk_end_request_all(req, -EIO);
continue;
}
@ -399,6 +411,7 @@ static void do_blkif_request(struct request_queue *rq)
static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
{
struct request_queue *rq;
struct blkfront_info *info = gd->private_data;
rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
if (rq == NULL)
@ -406,6 +419,13 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
if (info->feature_discard) {
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, rq);
blk_queue_max_discard_sectors(rq, get_capacity(gd));
rq->limits.discard_granularity = info->discard_granularity;
rq->limits.discard_alignment = info->discard_alignment;
}
/* Hard sector size and max sectors impersonate the equiv. hardware. */
blk_queue_logical_block_size(rq, sector_size);
blk_queue_max_hw_sectors(rq, 512);
@ -722,6 +742,17 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
switch (bret->operation) {
case BLKIF_OP_DISCARD:
if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
struct request_queue *rq = info->rq;
printk(KERN_WARNING "blkfront: %s: discard op failed\n",
info->gd->disk_name);
error = -EOPNOTSUPP;
info->feature_discard = 0;
queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
}
__blk_end_request_all(req, error);
break;
case BLKIF_OP_FLUSH_DISKCACHE:
case BLKIF_OP_WRITE_BARRIER:
if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
@ -1098,6 +1129,33 @@ blkfront_closing(struct blkfront_info *info)
bdput(bdev);
}
static void blkfront_setup_discard(struct blkfront_info *info)
{
int err;
char *type;
unsigned int discard_granularity;
unsigned int discard_alignment;
type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
if (IS_ERR(type))
return;
if (strncmp(type, "phy", 3) == 0) {
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
"discard-granularity", "%u", &discard_granularity,
"discard-alignment", "%u", &discard_alignment,
NULL);
if (!err) {
info->feature_discard = 1;
info->discard_granularity = discard_granularity;
info->discard_alignment = discard_alignment;
}
} else if (strncmp(type, "file", 4) == 0)
info->feature_discard = 1;
kfree(type);
}
/*
* Invoked when the backend is finally 'ready' (and has told produced
* the details about the physical device - #sectors, size, etc).
@ -1108,7 +1166,7 @@ static void blkfront_connect(struct blkfront_info *info)
unsigned long sector_size;
unsigned int binfo;
int err;
int barrier, flush;
int barrier, flush, discard;
switch (info->connected) {
case BLKIF_STATE_CONNECTED:
@ -1178,7 +1236,14 @@ static void blkfront_connect(struct blkfront_info *info)
info->feature_flush = REQ_FLUSH;
info->flush_op = BLKIF_OP_FLUSH_DISKCACHE;
}
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
"feature-discard", "%d", &discard,
NULL);
if (!err && discard)
blkfront_setup_discard(info);
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
if (err) {
xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
@ -1385,6 +1450,8 @@ static struct xenbus_driver blkfront = {
static int __init xlblk_init(void)
{
int ret;
if (!xen_domain())
return -ENODEV;
@ -1394,7 +1461,13 @@ static int __init xlblk_init(void)
return -ENODEV;
}
return xenbus_register_frontend(&blkfront);
ret = xenbus_register_frontend(&blkfront);
if (ret) {
unregister_blkdev(XENVBD_MAJOR, DEV_NAME);
return ret;
}
return 0;
}
module_init(xlblk_init);

36
include/xen/interface/io/blkif.h
View file

@ -57,6 +57,36 @@ typedef uint64_t blkif_sector_t;
* "feature-flush-cache" node!
*/
#define BLKIF_OP_FLUSH_DISKCACHE 3
/*
* Recognised only if "feature-discard" is present in backend xenbus info.
* The "feature-discard" node contains a boolean indicating whether trim
* (ATA) or unmap (SCSI) - conviently called discard requests are likely
* to succeed or fail. Either way, a discard request
* may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by
* the underlying block-device hardware. The boolean simply indicates whether
* or not it is worthwhile for the frontend to attempt discard requests.
* If a backend does not recognise BLKIF_OP_DISCARD, it should *not*
* create the "feature-discard" node!
*
* Discard operation is a request for the underlying block device to mark
* extents to be erased. However, discard does not guarantee that the blocks
* will be erased from the device - it is just a hint to the device
* controller that these blocks are no longer in use. What the device
* controller does with that information is left to the controller.
* Discard operations are passed with sector_number as the
* sector index to begin discard operations at and nr_sectors as the number of
* sectors to be discarded. The specified sectors should be discarded if the
* underlying block device supports trim (ATA) or unmap (SCSI) operations,
* or a BLKIF_RSP_EOPNOTSUPP should be returned.
* More information about trim/unmap operations at:
* http://t13.org/Documents/UploadedDocuments/docs2008/
* e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
* http://www.seagate.com/staticfiles/support/disc/manuals/
* Interface%20manuals/100293068c.pdf
*/
#define BLKIF_OP_DISCARD 5
/*
* Maximum scatter/gather segments per request.
* This is carefully chosen so that sizeof(struct blkif_ring) <= PAGE_SIZE.
@ -74,6 +104,11 @@ struct blkif_request_rw {
} seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};
struct blkif_request_discard {
blkif_sector_t sector_number;
uint64_t nr_sectors;
};
struct blkif_request {
uint8_t operation; /* BLKIF_OP_??? */
uint8_t nr_segments; /* number of segments */
@ -81,6 +116,7 @@ struct blkif_request {
uint64_t id; /* private guest value, echoed in resp */
union {
struct blkif_request_rw rw;
struct blkif_request_discard discard;
} u;
};