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-rw-r--r--drivers/block/xen-blkback/blkback.c134
-rw-r--r--drivers/block/xen-blkback/common.h98
-rw-r--r--drivers/block/xen-blkback/xenbus.c7
3 files changed, 198 insertions, 41 deletions
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 356722f65f88..1ebc0aa0f0e4 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -59,7 +59,7 @@
* IO workloads.
*/
-static int xen_blkif_max_buffer_pages = 704;
+static int xen_blkif_max_buffer_pages = 1024;
module_param_named(max_buffer_pages, xen_blkif_max_buffer_pages, int, 0644);
MODULE_PARM_DESC(max_buffer_pages,
"Maximum number of free pages to keep in each block backend buffer");
@@ -75,7 +75,7 @@ MODULE_PARM_DESC(max_buffer_pages,
* algorithm.
*/
-static int xen_blkif_max_pgrants = 352;
+static int xen_blkif_max_pgrants = 1056;
module_param_named(max_persistent_grants, xen_blkif_max_pgrants, int, 0644);
MODULE_PARM_DESC(max_persistent_grants,
"Maximum number of grants to map persistently");
@@ -636,10 +636,6 @@ purge_gnt_list:
return 0;
}
-struct seg_buf {
- unsigned int offset;
- unsigned int nsec;
-};
/*
* Unmap the grant references, and also remove the M2P over-rides
* used in the 'pending_req'.
@@ -818,29 +814,69 @@ out_of_memory:
return -ENOMEM;
}
-static int xen_blkbk_map_seg(struct blkif_request *req,
- struct pending_req *pending_req,
+static int xen_blkbk_map_seg(struct pending_req *pending_req,
struct seg_buf seg[],
struct page *pages[])
{
- int i, rc;
- grant_ref_t grefs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ int rc;
- for (i = 0; i < req->u.rw.nr_segments; i++)
- grefs[i] = req->u.rw.seg[i].gref;
-
- rc = xen_blkbk_map(pending_req->blkif, grefs,
+ rc = xen_blkbk_map(pending_req->blkif, pending_req->grefs,
pending_req->persistent_gnts,
pending_req->grant_handles, pending_req->pages,
- req->u.rw.nr_segments,
+ pending_req->nr_pages,
(pending_req->operation != BLKIF_OP_READ));
- if (rc)
- return rc;
- for (i = 0; i < req->u.rw.nr_segments; i++)
- seg[i].offset = (req->u.rw.seg[i].first_sect << 9);
+ return rc;
+}
- return 0;
+static int xen_blkbk_parse_indirect(struct blkif_request *req,
+ struct pending_req *pending_req,
+ struct seg_buf seg[],
+ struct phys_req *preq)
+{
+ struct persistent_gnt **persistent =
+ pending_req->indirect_persistent_gnts;
+ struct page **pages = pending_req->indirect_pages;
+ struct xen_blkif *blkif = pending_req->blkif;
+ int indirect_grefs, rc, n, nseg, i;
+ struct blkif_request_segment_aligned *segments = NULL;
+
+ nseg = pending_req->nr_pages;
+ indirect_grefs = INDIRECT_PAGES(nseg);
+ BUG_ON(indirect_grefs > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST);
+
+ rc = xen_blkbk_map(blkif, req->u.indirect.indirect_grefs,
+ persistent, pending_req->indirect_handles,
+ pages, indirect_grefs, true);
+ if (rc)
+ goto unmap;
+
+ for (n = 0, i = 0; n < nseg; n++) {
+ if ((n % SEGS_PER_INDIRECT_FRAME) == 0) {
+ /* Map indirect segments */
+ if (segments)
+ kunmap_atomic(segments);
+ segments = kmap_atomic(pages[n/SEGS_PER_INDIRECT_FRAME]);
+ }
+ i = n % SEGS_PER_INDIRECT_FRAME;
+ pending_req->grefs[n] = segments[i].gref;
+ seg[n].nsec = segments[i].last_sect -
+ segments[i].first_sect + 1;
+ seg[n].offset = (segments[i].first_sect << 9);
+ if ((segments[i].last_sect >= (PAGE_SIZE >> 9)) ||
+ (segments[i].last_sect < segments[i].first_sect)) {
+ rc = -EINVAL;
+ goto unmap;
+ }
+ preq->nr_sects += seg[n].nsec;
+ }
+
+unmap:
+ if (segments)
+ kunmap_atomic(segments);
+ xen_blkbk_unmap(blkif, pending_req->indirect_handles,
+ pages, persistent, indirect_grefs);
+ return rc;
}
static int dispatch_discard_io(struct xen_blkif *blkif,
@@ -1013,6 +1049,7 @@ __do_block_io_op(struct xen_blkif *blkif)
case BLKIF_OP_WRITE:
case BLKIF_OP_WRITE_BARRIER:
case BLKIF_OP_FLUSH_DISKCACHE:
+ case BLKIF_OP_INDIRECT:
if (dispatch_rw_block_io(blkif, &req, pending_req))
goto done;
break;
@@ -1059,17 +1096,28 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
struct pending_req *pending_req)
{
struct phys_req preq;
- struct seg_buf seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct seg_buf *seg = pending_req->seg;
unsigned int nseg;
struct bio *bio = NULL;
- struct bio *biolist[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct bio **biolist = pending_req->biolist;
int i, nbio = 0;
int operation;
struct blk_plug plug;
bool drain = false;
struct page **pages = pending_req->pages;
+ unsigned short req_operation;
+
+ req_operation = req->operation == BLKIF_OP_INDIRECT ?
+ req->u.indirect.indirect_op : req->operation;
+ if ((req->operation == BLKIF_OP_INDIRECT) &&
+ (req_operation != BLKIF_OP_READ) &&
+ (req_operation != BLKIF_OP_WRITE)) {
+ pr_debug(DRV_PFX "Invalid indirect operation (%u)\n",
+ req_operation);
+ goto fail_response;
+ }
- switch (req->operation) {
+ switch (req_operation) {
case BLKIF_OP_READ:
blkif->st_rd_req++;
operation = READ;
@@ -1091,33 +1139,47 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
}
/* Check that the number of segments is sane. */
- nseg = req->u.rw.nr_segments;
+ nseg = req->operation == BLKIF_OP_INDIRECT ?
+ req->u.indirect.nr_segments : req->u.rw.nr_segments;
if (unlikely(nseg == 0 && operation != WRITE_FLUSH) ||
- unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
+ unlikely((req->operation != BLKIF_OP_INDIRECT) &&
+ (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) ||
+ unlikely((req->operation == BLKIF_OP_INDIRECT) &&
+ (nseg > MAX_INDIRECT_SEGMENTS))) {
pr_debug(DRV_PFX "Bad number of segments in request (%d)\n",
nseg);
/* Haven't submitted any bio's yet. */
goto fail_response;
}
- preq.sector_number = req->u.rw.sector_number;
preq.nr_sects = 0;
pending_req->blkif = blkif;
pending_req->id = req->u.rw.id;
- pending_req->operation = req->operation;
+ pending_req->operation = req_operation;
pending_req->status = BLKIF_RSP_OKAY;
pending_req->nr_pages = nseg;
- for (i = 0; i < nseg; i++) {
- seg[i].nsec = req->u.rw.seg[i].last_sect -
- req->u.rw.seg[i].first_sect + 1;
- if ((req->u.rw.seg[i].last_sect >= (PAGE_SIZE >> 9)) ||
- (req->u.rw.seg[i].last_sect < req->u.rw.seg[i].first_sect))
+ if (req->operation != BLKIF_OP_INDIRECT) {
+ preq.dev = req->u.rw.handle;
+ preq.sector_number = req->u.rw.sector_number;
+ for (i = 0; i < nseg; i++) {
+ pending_req->grefs[i] = req->u.rw.seg[i].gref;
+ seg[i].nsec = req->u.rw.seg[i].last_sect -
+ req->u.rw.seg[i].first_sect + 1;
+ seg[i].offset = (req->u.rw.seg[i].first_sect << 9);
+ if ((req->u.rw.seg[i].last_sect >= (PAGE_SIZE >> 9)) ||
+ (req->u.rw.seg[i].last_sect <
+ req->u.rw.seg[i].first_sect))
+ goto fail_response;
+ preq.nr_sects += seg[i].nsec;
+ }
+ } else {
+ preq.dev = req->u.indirect.handle;
+ preq.sector_number = req->u.indirect.sector_number;
+ if (xen_blkbk_parse_indirect(req, pending_req, seg, &preq))
goto fail_response;
- preq.nr_sects += seg[i].nsec;
-
}
if (xen_vbd_translate(&preq, blkif, operation) != 0) {
@@ -1154,7 +1216,7 @@ 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 (xen_blkbk_map_seg(req, pending_req, seg, pages))
+ if (xen_blkbk_map_seg(pending_req, seg, pages))
goto fail_flush;
/*
@@ -1220,7 +1282,7 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
pending_req->nr_pages);
fail_response:
/* Haven't submitted any bio's yet. */
- make_response(blkif, req->u.rw.id, req->operation, BLKIF_RSP_ERROR);
+ make_response(blkif, req->u.rw.id, req_operation, BLKIF_RSP_ERROR);
free_req(blkif, pending_req);
msleep(1); /* back off a bit */
return -EIO;
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index e33fafa0facd..1ac53da8410f 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -50,6 +50,19 @@
__func__, __LINE__, ##args)
+/*
+ * This is the maximum number of segments that would be allowed in indirect
+ * requests. This value will also be passed to the frontend.
+ */
+#define MAX_INDIRECT_SEGMENTS 256
+
+#define SEGS_PER_INDIRECT_FRAME \
+ (PAGE_SIZE/sizeof(struct blkif_request_segment_aligned))
+#define MAX_INDIRECT_PAGES \
+ ((MAX_INDIRECT_SEGMENTS + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
+#define INDIRECT_PAGES(_segs) \
+ ((_segs + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
+
/* Not a real protocol. Used to generate ring structs which contain
* the elements common to all protocols only. This way we get a
* compiler-checkable way to use common struct elements, so we can
@@ -83,12 +96,31 @@ struct blkif_x86_32_request_other {
uint64_t id; /* private guest value, echoed in resp */
} __attribute__((__packed__));
+struct blkif_x86_32_request_indirect {
+ uint8_t indirect_op;
+ uint16_t nr_segments;
+ uint64_t id;
+ blkif_sector_t sector_number;
+ blkif_vdev_t handle;
+ uint16_t _pad1;
+ grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
+ /*
+ * The maximum number of indirect segments (and pages) that will
+ * be used is determined by MAX_INDIRECT_SEGMENTS, this value
+ * is also exported to the guest (via xenstore
+ * feature-max-indirect-segments entry), so the frontend knows how
+ * many indirect segments the backend supports.
+ */
+ uint64_t _pad2; /* make it 64 byte aligned */
+} __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;
struct blkif_x86_32_request_other other;
+ struct blkif_x86_32_request_indirect indirect;
} u;
} __attribute__((__packed__));
@@ -127,12 +159,32 @@ struct blkif_x86_64_request_other {
uint64_t id; /* private guest value, echoed in resp */
} __attribute__((__packed__));
+struct blkif_x86_64_request_indirect {
+ uint8_t indirect_op;
+ uint16_t nr_segments;
+ uint32_t _pad1; /* offsetof(blkif_..,u.indirect.id)==8 */
+ uint64_t id;
+ blkif_sector_t sector_number;
+ blkif_vdev_t handle;
+ uint16_t _pad2;
+ grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
+ /*
+ * The maximum number of indirect segments (and pages) that will
+ * be used is determined by MAX_INDIRECT_SEGMENTS, this value
+ * is also exported to the guest (via xenstore
+ * feature-max-indirect-segments entry), so the frontend knows how
+ * many indirect segments the backend supports.
+ */
+ uint32_t _pad3; /* make it 64 byte aligned */
+} __attribute__((__packed__));
+
struct blkif_x86_64_request {
uint8_t operation; /* BLKIF_OP_??? */
union {
struct blkif_x86_64_request_rw rw;
struct blkif_x86_64_request_discard discard;
struct blkif_x86_64_request_other other;
+ struct blkif_x86_64_request_indirect indirect;
} u;
} __attribute__((__packed__));
@@ -266,6 +318,11 @@ struct xen_blkif {
wait_queue_head_t waiting_to_free;
};
+struct seg_buf {
+ unsigned long offset;
+ unsigned int nsec;
+};
+
/*
* Each outstanding request that we've passed to the lower device layers has a
* 'pending_req' allocated to it. Each buffer_head that completes decrements
@@ -280,9 +337,16 @@ struct pending_req {
unsigned short operation;
int status;
struct list_head free_list;
- struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
- struct persistent_gnt *persistent_gnts[BLKIF_MAX_SEGMENTS_PER_REQUEST];
- grant_handle_t grant_handles[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct page *pages[MAX_INDIRECT_SEGMENTS];
+ struct persistent_gnt *persistent_gnts[MAX_INDIRECT_SEGMENTS];
+ grant_handle_t grant_handles[MAX_INDIRECT_SEGMENTS];
+ grant_ref_t grefs[MAX_INDIRECT_SEGMENTS];
+ /* Indirect descriptors */
+ struct persistent_gnt *indirect_persistent_gnts[MAX_INDIRECT_PAGES];
+ struct page *indirect_pages[MAX_INDIRECT_PAGES];
+ grant_handle_t indirect_handles[MAX_INDIRECT_PAGES];
+ struct seg_buf seg[MAX_INDIRECT_SEGMENTS];
+ struct bio *biolist[MAX_INDIRECT_SEGMENTS];
};
@@ -321,7 +385,7 @@ struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
static inline void blkif_get_x86_32_req(struct blkif_request *dst,
struct blkif_x86_32_request *src)
{
- int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j;
dst->operation = src->operation;
switch (src->operation) {
case BLKIF_OP_READ:
@@ -344,6 +408,18 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst,
dst->u.discard.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;
+ case BLKIF_OP_INDIRECT:
+ dst->u.indirect.indirect_op = src->u.indirect.indirect_op;
+ dst->u.indirect.nr_segments = src->u.indirect.nr_segments;
+ dst->u.indirect.handle = src->u.indirect.handle;
+ dst->u.indirect.id = src->u.indirect.id;
+ dst->u.indirect.sector_number = src->u.indirect.sector_number;
+ barrier();
+ j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments));
+ for (i = 0; i < j; i++)
+ dst->u.indirect.indirect_grefs[i] =
+ src->u.indirect.indirect_grefs[i];
+ break;
default:
/*
* Don't know how to translate this op. Only get the
@@ -357,7 +433,7 @@ static inline void blkif_get_x86_32_req(struct blkif_request *dst,
static inline void blkif_get_x86_64_req(struct blkif_request *dst,
struct blkif_x86_64_request *src)
{
- int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j;
dst->operation = src->operation;
switch (src->operation) {
case BLKIF_OP_READ:
@@ -380,6 +456,18 @@ static inline void blkif_get_x86_64_req(struct blkif_request *dst,
dst->u.discard.sector_number = src->u.discard.sector_number;
dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
break;
+ case BLKIF_OP_INDIRECT:
+ dst->u.indirect.indirect_op = src->u.indirect.indirect_op;
+ dst->u.indirect.nr_segments = src->u.indirect.nr_segments;
+ dst->u.indirect.handle = src->u.indirect.handle;
+ dst->u.indirect.id = src->u.indirect.id;
+ dst->u.indirect.sector_number = src->u.indirect.sector_number;
+ barrier();
+ j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments));
+ for (i = 0; i < j; i++)
+ dst->u.indirect.indirect_grefs[i] =
+ src->u.indirect.indirect_grefs[i];
+ break;
default:
/*
* Don't know how to translate this op. Only get the
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 1f1ade6d6e09..afab208c54e3 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -107,6 +107,8 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
struct xen_blkif *blkif;
int i;
+ BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST);
+
blkif = kmem_cache_zalloc(xen_blkif_cachep, GFP_KERNEL);
if (!blkif)
return ERR_PTR(-ENOMEM);
@@ -709,6 +711,11 @@ again:
dev->nodename);
goto abort;
}
+ err = xenbus_printf(xbt, dev->nodename, "feature-max-indirect-segments", "%u",
+ MAX_INDIRECT_SEGMENTS);
+ if (err)
+ dev_warn(&dev->dev, "writing %s/feature-max-indirect-segments (%d)",
+ dev->nodename, err);
err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
(unsigned long long)vbd_sz(&be->blkif->vbd));