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Merge branch 'stable/for-jens-3.2' of git://oss.oracle.com/git/kwilk/…
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…xen into for-3.2/drivers
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@axboe
axboe committed Oct 20, 2011
2 parents 4c823cc + 6927d92 commit b8d8bdf
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Showing 5 changed files with 403 additions and 66 deletions.
130 changes: 109 additions & 21 deletions drivers/block/xen-blkback/blkback.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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()
*/
Expand All @@ -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);
Expand All @@ -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);
}
}
Expand Down Expand Up @@ -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.
Expand All @@ -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:
Expand All @@ -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;
Expand All @@ -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);
Expand Down Expand Up @@ -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++) {
Expand All @@ -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;
}
}

/*
Expand All @@ -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;
Expand Down Expand Up @@ -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);
Expand All @@ -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);
Expand Down
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