* 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");
* 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");
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'.
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,
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;
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;
}
/* 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) {
* 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;
/*
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;
__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
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__));
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__));
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
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];
};
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:
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
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:
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
struct blk_shadow {
struct blkif_request req;
struct request *request;
- struct grant *grants_used[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct grant **grants_used;
+ struct grant **indirect_grants;
+};
+
+struct split_bio {
+ struct bio *bio;
+ atomic_t pending;
+ int err;
};
static DEFINE_MUTEX(blkfront_mutex);
static const struct block_device_operations xlvbd_block_fops;
+/*
+ * Maximum number of segments in indirect requests, the actual value used by
+ * the frontend driver is the minimum of this value and the value provided
+ * by the backend driver.
+ */
+
+static unsigned int xen_blkif_max_segments = 32;
+
#define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
/*
enum blkif_state connected;
int ring_ref;
struct blkif_front_ring ring;
- struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct scatterlist *sg;
unsigned int evtchn, irq;
struct request_queue *rq;
struct work_struct work;
unsigned int discard_granularity;
unsigned int discard_alignment;
unsigned int feature_persistent:1;
+ unsigned int max_indirect_segments;
int is_ready;
};
#define DEV_NAME "xvd" /* name in /dev */
+#define SEGS_PER_INDIRECT_FRAME \
+ (PAGE_SIZE/sizeof(struct blkif_request_segment_aligned))
+#define INDIRECT_GREFS(_segs) \
+ ((_segs + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
+
+static int blkfront_setup_indirect(struct blkfront_info *info);
+
static int get_id_from_freelist(struct blkfront_info *info)
{
unsigned long free = info->shadow_free;
struct blkif_request *ring_req;
unsigned long id;
unsigned int fsect, lsect;
- int i, ref;
+ int i, ref, n;
+ struct blkif_request_segment_aligned *segments = NULL;
/*
* Used to store if we are able to queue the request by just using
grant_ref_t gref_head;
struct grant *gnt_list_entry = NULL;
struct scatterlist *sg;
+ int nseg, max_grefs;
if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
return 1;
- /* Check if we have enought grants to allocate a requests */
- if (info->persistent_gnts_c < BLKIF_MAX_SEGMENTS_PER_REQUEST) {
+ max_grefs = info->max_indirect_segments ?
+ info->max_indirect_segments +
+ INDIRECT_GREFS(info->max_indirect_segments) :
+ BLKIF_MAX_SEGMENTS_PER_REQUEST;
+
+ /* Check if we have enough grants to allocate a requests */
+ if (info->persistent_gnts_c < max_grefs) {
new_persistent_gnts = 1;
if (gnttab_alloc_grant_references(
- BLKIF_MAX_SEGMENTS_PER_REQUEST - info->persistent_gnts_c,
+ max_grefs - info->persistent_gnts_c,
&gref_head) < 0) {
gnttab_request_free_callback(
&info->callback,
blkif_restart_queue_callback,
info,
- BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ max_grefs);
return 1;
}
} else
id = get_id_from_freelist(info);
info->shadow[id].request = req;
- ring_req->u.rw.id = id;
- ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req);
- ring_req->u.rw.handle = info->handle;
-
- ring_req->operation = rq_data_dir(req) ?
- BLKIF_OP_WRITE : BLKIF_OP_READ;
-
- if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
- /*
- * Ideally we can do an unordered flush-to-disk. In case the
- * backend onlysupports barriers, use that. A barrier request
- * a superset of FUA, so we can implement it the same
- * way. (It's also a FLUSH+FUA, since it is
- * guaranteed ordered WRT previous writes.)
- */
- ring_req->operation = info->flush_op;
- }
-
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->u.discard.nr_sectors = blk_rq_sectors(req);
+ ring_req->u.discard.id = id;
+ ring_req->u.discard.sector_number = (blkif_sector_t)blk_rq_pos(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->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->u.rw.nr_segments, i) {
+ BUG_ON(info->max_indirect_segments == 0 &&
+ req->nr_phys_segments > BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ BUG_ON(info->max_indirect_segments &&
+ req->nr_phys_segments > info->max_indirect_segments);
+ nseg = blk_rq_map_sg(req->q, req, info->sg);
+ ring_req->u.rw.id = id;
+ if (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST) {
+ /*
+ * The indirect operation can only be a BLKIF_OP_READ or
+ * BLKIF_OP_WRITE
+ */
+ BUG_ON(req->cmd_flags & (REQ_FLUSH | REQ_FUA));
+ ring_req->operation = BLKIF_OP_INDIRECT;
+ ring_req->u.indirect.indirect_op = rq_data_dir(req) ?
+ BLKIF_OP_WRITE : BLKIF_OP_READ;
+ ring_req->u.indirect.sector_number = (blkif_sector_t)blk_rq_pos(req);
+ ring_req->u.indirect.handle = info->handle;
+ ring_req->u.indirect.nr_segments = nseg;
+ } else {
+ ring_req->u.rw.sector_number = (blkif_sector_t)blk_rq_pos(req);
+ ring_req->u.rw.handle = info->handle;
+ ring_req->operation = rq_data_dir(req) ?
+ BLKIF_OP_WRITE : BLKIF_OP_READ;
+ if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
+ /*
+ * Ideally we can do an unordered flush-to-disk. In case the
+ * backend onlysupports barriers, use that. A barrier request
+ * a superset of FUA, so we can implement it the same
+ * way. (It's also a FLUSH+FUA, since it is
+ * guaranteed ordered WRT previous writes.)
+ */
+ ring_req->operation = info->flush_op;
+ }
+ ring_req->u.rw.nr_segments = nseg;
+ }
+ for_each_sg(info->sg, sg, nseg, i) {
fsect = sg->offset >> 9;
lsect = fsect + (sg->length >> 9) - 1;
+ if ((ring_req->operation == BLKIF_OP_INDIRECT) &&
+ (i % SEGS_PER_INDIRECT_FRAME == 0)) {
+ if (segments)
+ kunmap_atomic(segments);
+
+ n = i / SEGS_PER_INDIRECT_FRAME;
+ gnt_list_entry = get_grant(&gref_head, info);
+ info->shadow[id].indirect_grants[n] = gnt_list_entry;
+ segments = kmap_atomic(pfn_to_page(gnt_list_entry->pfn));
+ ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref;
+ }
+
gnt_list_entry = get_grant(&gref_head, info);
ref = gnt_list_entry->gref;
BUG_ON(sg->offset + sg->length > PAGE_SIZE);
- shared_data = kmap_atomic(
- pfn_to_page(gnt_list_entry->pfn));
+ shared_data = kmap_atomic(pfn_to_page(gnt_list_entry->pfn));
bvec_data = kmap_atomic(sg_page(sg));
/*
kunmap_atomic(bvec_data);
kunmap_atomic(shared_data);
}
-
- ring_req->u.rw.seg[i] =
- (struct blkif_request_segment) {
- .gref = ref,
- .first_sect = fsect,
- .last_sect = lsect };
+ if (ring_req->operation != BLKIF_OP_INDIRECT) {
+ ring_req->u.rw.seg[i] =
+ (struct blkif_request_segment) {
+ .gref = ref,
+ .first_sect = fsect,
+ .last_sect = lsect };
+ } else {
+ n = i % SEGS_PER_INDIRECT_FRAME;
+ segments[n] =
+ (struct blkif_request_segment_aligned) {
+ .gref = ref,
+ .first_sect = fsect,
+ .last_sect = lsect };
+ }
}
+ if (segments)
+ kunmap_atomic(segments);
}
info->ring.req_prod_pvt++;
flush_requests(info);
}
-static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
+static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
+ unsigned int segments)
{
struct request_queue *rq;
struct blkfront_info *info = gd->private_data;
blk_queue_max_segment_size(rq, PAGE_SIZE);
/* Ensure a merged request will fit in a single I/O ring slot. */
- blk_queue_max_segments(rq, BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ blk_queue_max_segments(rq, segments);
/* Make sure buffer addresses are sector-aligned. */
blk_queue_dma_alignment(rq, 511);
static void xlvbd_flush(struct blkfront_info *info)
{
blk_queue_flush(info->rq, info->feature_flush);
- printk(KERN_INFO "blkfront: %s: %s: %s %s\n",
+ printk(KERN_INFO "blkfront: %s: %s: %s %s %s %s %s\n",
info->gd->disk_name,
info->flush_op == BLKIF_OP_WRITE_BARRIER ?
"barrier" : (info->flush_op == BLKIF_OP_FLUSH_DISKCACHE ?
"flush diskcache" : "barrier or flush"),
- info->feature_flush ? "enabled" : "disabled",
- info->feature_persistent ? "using persistent grants" : "");
+ info->feature_flush ? "enabled;" : "disabled;",
+ "persistent grants:",
+ info->feature_persistent ? "enabled;" : "disabled;",
+ "indirect descriptors:",
+ info->max_indirect_segments ? "enabled;" : "disabled;");
}
static int xen_translate_vdev(int vdevice, int *minor, unsigned int *offset)
gd->driverfs_dev = &(info->xbdev->dev);
set_capacity(gd, capacity);
- if (xlvbd_init_blk_queue(gd, sector_size)) {
+ if (xlvbd_init_blk_queue(gd, sector_size,
+ info->max_indirect_segments ? :
+ BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
del_gendisk(gd);
goto release;
}
{
struct grant *persistent_gnt;
struct grant *n;
+ int i, j, segs;
/* Prevent new requests being issued until we fix things up. */
spin_lock_irq(&info->io_lock);
}
BUG_ON(info->persistent_gnts_c != 0);
+ kfree(info->sg);
+ info->sg = NULL;
+ for (i = 0; i < BLK_RING_SIZE; i++) {
+ /*
+ * Clear persistent grants present in requests already
+ * on the shared ring
+ */
+ if (!info->shadow[i].request)
+ goto free_shadow;
+
+ segs = info->shadow[i].req.operation == BLKIF_OP_INDIRECT ?
+ info->shadow[i].req.u.indirect.nr_segments :
+ info->shadow[i].req.u.rw.nr_segments;
+ for (j = 0; j < segs; j++) {
+ persistent_gnt = info->shadow[i].grants_used[j];
+ gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
+ __free_page(pfn_to_page(persistent_gnt->pfn));
+ kfree(persistent_gnt);
+ }
+
+ if (info->shadow[i].req.operation != BLKIF_OP_INDIRECT)
+ /*
+ * If this is not an indirect operation don't try to
+ * free indirect segments
+ */
+ goto free_shadow;
+
+ for (j = 0; j < INDIRECT_GREFS(segs); j++) {
+ persistent_gnt = info->shadow[i].indirect_grants[j];
+ gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
+ __free_page(pfn_to_page(persistent_gnt->pfn));
+ kfree(persistent_gnt);
+ }
+
+free_shadow:
+ kfree(info->shadow[i].grants_used);
+ info->shadow[i].grants_used = NULL;
+ kfree(info->shadow[i].indirect_grants);
+ info->shadow[i].indirect_grants = NULL;
+ }
+
/* No more gnttab callback work. */
gnttab_cancel_free_callback(&info->callback);
spin_unlock_irq(&info->io_lock);
char *bvec_data;
void *shared_data;
unsigned int offset = 0;
+ int nseg;
+
+ nseg = s->req.operation == BLKIF_OP_INDIRECT ?
+ s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments;
if (bret->operation == BLKIF_OP_READ) {
/*
BUG_ON((bvec->bv_offset + bvec->bv_len) > PAGE_SIZE);
if (bvec->bv_offset < offset)
i++;
- BUG_ON(i >= s->req.u.rw.nr_segments);
+ BUG_ON(i >= nseg);
shared_data = kmap_atomic(
pfn_to_page(s->grants_used[i]->pfn));
bvec_data = bvec_kmap_irq(bvec, &flags);
}
}
/* Add the persistent grant into the list of free grants */
- for (i = 0; i < s->req.u.rw.nr_segments; i++) {
+ for (i = 0; i < nseg; i++) {
list_add(&s->grants_used[i]->node, &info->persistent_gnts);
info->persistent_gnts_c++;
}
+ if (s->req.operation == BLKIF_OP_INDIRECT) {
+ for (i = 0; i < INDIRECT_GREFS(nseg); i++) {
+ list_add(&s->indirect_grants[i]->node, &info->persistent_gnts);
+ info->persistent_gnts_c++;
+ }
+ }
}
static irqreturn_t blkif_interrupt(int irq, void *dev_id)
SHARED_RING_INIT(sring);
FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
- sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
-
- /* Allocate memory for grants */
- err = fill_grant_buffer(info, BLK_RING_SIZE *
- BLKIF_MAX_SEGMENTS_PER_REQUEST);
- if (err)
- goto fail;
-
err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
if (err < 0) {
free_page((unsigned long)sring);
return 0;
}
+/*
+ * This is a clone of md_trim_bio, used to split a bio into smaller ones
+ */
+static void trim_bio(struct bio *bio, int offset, int size)
+{
+ /* 'bio' is a cloned bio which we need to trim to match
+ * the given offset and size.
+ * This requires adjusting bi_sector, bi_size, and bi_io_vec
+ */
+ int i;
+ struct bio_vec *bvec;
+ int sofar = 0;
+
+ size <<= 9;
+ if (offset == 0 && size == bio->bi_size)
+ return;
+
+ bio->bi_sector += offset;
+ bio->bi_size = size;
+ offset <<= 9;
+ clear_bit(BIO_SEG_VALID, &bio->bi_flags);
+
+ while (bio->bi_idx < bio->bi_vcnt &&
+ bio->bi_io_vec[bio->bi_idx].bv_len <= offset) {
+ /* remove this whole bio_vec */
+ offset -= bio->bi_io_vec[bio->bi_idx].bv_len;
+ bio->bi_idx++;
+ }
+ if (bio->bi_idx < bio->bi_vcnt) {
+ bio->bi_io_vec[bio->bi_idx].bv_offset += offset;
+ bio->bi_io_vec[bio->bi_idx].bv_len -= offset;
+ }
+ /* avoid any complications with bi_idx being non-zero*/
+ if (bio->bi_idx) {
+ memmove(bio->bi_io_vec, bio->bi_io_vec+bio->bi_idx,
+ (bio->bi_vcnt - bio->bi_idx) * sizeof(struct bio_vec));
+ bio->bi_vcnt -= bio->bi_idx;
+ bio->bi_idx = 0;
+ }
+ /* Make sure vcnt and last bv are not too big */
+ bio_for_each_segment(bvec, bio, i) {
+ if (sofar + bvec->bv_len > size)
+ bvec->bv_len = size - sofar;
+ if (bvec->bv_len == 0) {
+ bio->bi_vcnt = i;
+ break;
+ }
+ sofar += bvec->bv_len;
+ }
+}
+
+static void split_bio_end(struct bio *bio, int error)
+{
+ struct split_bio *split_bio = bio->bi_private;
+
+ if (error)
+ split_bio->err = error;
+
+ if (atomic_dec_and_test(&split_bio->pending)) {
+ split_bio->bio->bi_phys_segments = 0;
+ bio_endio(split_bio->bio, split_bio->err);
+ kfree(split_bio);
+ }
+ bio_put(bio);
+}
static int blkif_recover(struct blkfront_info *info)
{
int i;
- struct blkif_request *req;
+ struct request *req, *n;
struct blk_shadow *copy;
- int j;
+ int rc;
+ struct bio *bio, *cloned_bio;
+ struct bio_list bio_list, merge_bio;
+ unsigned int segs, offset;
+ int pending, size;
+ struct split_bio *split_bio;
+ struct list_head requests;
/* Stage 1: Make a safe copy of the shadow state. */
copy = kmemdup(info->shadow, sizeof(info->shadow),
info->shadow_free = info->ring.req_prod_pvt;
info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
- /* Stage 3: Find pending requests and requeue them. */
+ rc = blkfront_setup_indirect(info);
+ if (rc) {
+ kfree(copy);
+ return rc;
+ }
+
+ segs = info->max_indirect_segments ? : BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ blk_queue_max_segments(info->rq, segs);
+ bio_list_init(&bio_list);
+ INIT_LIST_HEAD(&requests);
for (i = 0; i < BLK_RING_SIZE; i++) {
/* Not in use? */
if (!copy[i].request)
continue;
- /* Grab a request slot and copy shadow state into it. */
- req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
- *req = copy[i].req;
-
- /* We get a new request id, and must reset the shadow state. */
- req->u.rw.id = get_id_from_freelist(info);
- memcpy(&info->shadow[req->u.rw.id], ©[i], sizeof(copy[i]));
-
- if (req->operation != BLKIF_OP_DISCARD) {
- /* Rewrite any grant references invalidated by susp/resume. */
- 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(copy[i].grants_used[j]->pfn),
- 0);
+ /*
+ * Get the bios in the request so we can re-queue them.
+ */
+ if (copy[i].request->cmd_flags &
+ (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
+ /*
+ * Flush operations don't contain bios, so
+ * we need to requeue the whole request
+ */
+ list_add(©[i].request->queuelist, &requests);
+ continue;
}
- info->shadow[req->u.rw.id].req = *req;
-
- info->ring.req_prod_pvt++;
+ merge_bio.head = copy[i].request->bio;
+ merge_bio.tail = copy[i].request->biotail;
+ bio_list_merge(&bio_list, &merge_bio);
+ copy[i].request->bio = NULL;
+ blk_put_request(copy[i].request);
}
kfree(copy);
+ /*
+ * Empty the queue, this is important because we might have
+ * requests in the queue with more segments than what we
+ * can handle now.
+ */
+ spin_lock_irq(&info->io_lock);
+ while ((req = blk_fetch_request(info->rq)) != NULL) {
+ if (req->cmd_flags &
+ (REQ_FLUSH | REQ_FUA | REQ_DISCARD | REQ_SECURE)) {
+ list_add(&req->queuelist, &requests);
+ continue;
+ }
+ merge_bio.head = req->bio;
+ merge_bio.tail = req->biotail;
+ bio_list_merge(&bio_list, &merge_bio);
+ req->bio = NULL;
+ if (req->cmd_flags & (REQ_FLUSH | REQ_FUA))
+ pr_alert("diskcache flush request found!\n");
+ __blk_put_request(info->rq, req);
+ }
+ spin_unlock_irq(&info->io_lock);
+
xenbus_switch_state(info->xbdev, XenbusStateConnected);
spin_lock_irq(&info->io_lock);
/* Now safe for us to use the shared ring */
info->connected = BLKIF_STATE_CONNECTED;
- /* Send off requeued requests */
- flush_requests(info);
-
/* Kick any other new requests queued since we resumed */
kick_pending_request_queues(info);
+ list_for_each_entry_safe(req, n, &requests, queuelist) {
+ /* Requeue pending requests (flush or discard) */
+ list_del_init(&req->queuelist);
+ BUG_ON(req->nr_phys_segments > segs);
+ blk_requeue_request(info->rq, req);
+ }
spin_unlock_irq(&info->io_lock);
+ while ((bio = bio_list_pop(&bio_list)) != NULL) {
+ /* Traverse the list of pending bios and re-queue them */
+ if (bio_segments(bio) > segs) {
+ /*
+ * This bio has more segments than what we can
+ * handle, we have to split it.
+ */
+ pending = (bio_segments(bio) + segs - 1) / segs;
+ split_bio = kzalloc(sizeof(*split_bio), GFP_NOIO);
+ BUG_ON(split_bio == NULL);
+ atomic_set(&split_bio->pending, pending);
+ split_bio->bio = bio;
+ for (i = 0; i < pending; i++) {
+ offset = (i * segs * PAGE_SIZE) >> 9;
+ size = min((unsigned int)(segs * PAGE_SIZE) >> 9,
+ (unsigned int)(bio->bi_size >> 9) - offset);
+ cloned_bio = bio_clone(bio, GFP_NOIO);
+ BUG_ON(cloned_bio == NULL);
+ trim_bio(cloned_bio, offset, size);
+ cloned_bio->bi_private = split_bio;
+ cloned_bio->bi_end_io = split_bio_end;
+ submit_bio(cloned_bio->bi_rw, cloned_bio);
+ }
+ /*
+ * Now we have to wait for all those smaller bios to
+ * end, so we can also end the "parent" bio.
+ */
+ continue;
+ }
+ /* We don't need to split this bio */
+ submit_bio(bio->bi_rw, bio);
+ }
+
return 0;
}
blkif_free(info, info->connected == BLKIF_STATE_CONNECTED);
err = talk_to_blkback(dev, info);
- if (info->connected == BLKIF_STATE_SUSPENDED && !err)
- err = blkif_recover(info);
+
+ /*
+ * We have to wait for the backend to switch to
+ * connected state, since we want to read which
+ * features it supports.
+ */
return err;
}
kfree(type);
}
+static int blkfront_setup_indirect(struct blkfront_info *info)
+{
+ unsigned int indirect_segments, segs;
+ int err, i;
+
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-max-indirect-segments", "%u", &indirect_segments,
+ NULL);
+ if (err) {
+ info->max_indirect_segments = 0;
+ segs = BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ } else {
+ info->max_indirect_segments = min(indirect_segments,
+ xen_blkif_max_segments);
+ segs = info->max_indirect_segments;
+ }
+ info->sg = kzalloc(sizeof(info->sg[0]) * segs, GFP_KERNEL);
+ if (info->sg == NULL)
+ goto out_of_memory;
+ sg_init_table(info->sg, segs);
+
+ err = fill_grant_buffer(info, (segs + INDIRECT_GREFS(segs)) * BLK_RING_SIZE);
+ if (err)
+ goto out_of_memory;
+
+ for (i = 0; i < BLK_RING_SIZE; i++) {
+ info->shadow[i].grants_used = kzalloc(
+ sizeof(info->shadow[i].grants_used[0]) * segs,
+ GFP_NOIO);
+ if (info->max_indirect_segments)
+ info->shadow[i].indirect_grants = kzalloc(
+ sizeof(info->shadow[i].indirect_grants[0]) *
+ INDIRECT_GREFS(segs),
+ GFP_NOIO);
+ if ((info->shadow[i].grants_used == NULL) ||
+ (info->max_indirect_segments &&
+ (info->shadow[i].indirect_grants == NULL)))
+ goto out_of_memory;
+ }
+
+
+ return 0;
+
+out_of_memory:
+ kfree(info->sg);
+ info->sg = NULL;
+ for (i = 0; i < BLK_RING_SIZE; i++) {
+ kfree(info->shadow[i].grants_used);
+ info->shadow[i].grants_used = NULL;
+ kfree(info->shadow[i].indirect_grants);
+ info->shadow[i].indirect_grants = NULL;
+ }
+ return -ENOMEM;
+}
+
/*
* Invoked when the backend is finally 'ready' (and has told produced
* the details about the physical device - #sectors, size, etc).
set_capacity(info->gd, sectors);
revalidate_disk(info->gd);
- /* fall through */
+ return;
case BLKIF_STATE_SUSPENDED:
+ /*
+ * If we are recovering from suspension, we need to wait
+ * for the backend to announce it's features before
+ * reconnecting, at least we need to know if the backend
+ * supports indirect descriptors, and how many.
+ */
+ blkif_recover(info);
return;
default:
else
info->feature_persistent = persistent;
+ err = blkfront_setup_indirect(info);
+ if (err) {
+ xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s",
+ info->xbdev->otherend);
+ return;
+ }
+
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
if (err) {
xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
projects / firefly-linux-kernel-4.4.55.git / commitdiff