struct blkif_request req;
struct request *request;
struct grant *grants_used[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};
static DEFINE_MUTEX(blkfront_mutex);
enum blkif_state connected;
int ring_ref;
struct blkif_front_ring ring;
- struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
unsigned int evtchn, irq;
struct request_queue *rq;
struct work_struct work;
struct gnttab_free_callback callback;
struct blk_shadow shadow[BLK_RING_SIZE];
- struct list_head persistent_gnts;
+ struct list_head grants;
unsigned int persistent_gnts_c;
unsigned long shadow_free;
unsigned int feature_flush;
if (!gnt_list_entry)
goto out_of_memory;
- granted_page = alloc_page(GFP_NOIO);
- if (!granted_page) {
- kfree(gnt_list_entry);
- goto out_of_memory;
+ if (info->feature_persistent) {
+ granted_page = alloc_page(GFP_NOIO);
+ if (!granted_page) {
+ kfree(gnt_list_entry);
+ goto out_of_memory;
+ }
+ gnt_list_entry->pfn = page_to_pfn(granted_page);
}
- gnt_list_entry->pfn = page_to_pfn(granted_page);
gnt_list_entry->gref = GRANT_INVALID_REF;
- list_add(&gnt_list_entry->node, &info->persistent_gnts);
+ list_add(&gnt_list_entry->node, &info->grants);
i++;
}
out_of_memory:
list_for_each_entry_safe(gnt_list_entry, n,
- &info->persistent_gnts, node) {
+ &info->grants, node) {
list_del(&gnt_list_entry->node);
- __free_page(pfn_to_page(gnt_list_entry->pfn));
+ if (info->feature_persistent)
+ __free_page(pfn_to_page(gnt_list_entry->pfn));
kfree(gnt_list_entry);
i--;
}
}
static struct grant *get_grant(grant_ref_t *gref_head,
+ unsigned long pfn,
struct blkfront_info *info)
{
struct grant *gnt_list_entry;
unsigned long buffer_mfn;
- BUG_ON(list_empty(&info->persistent_gnts));
- gnt_list_entry = list_first_entry(&info->persistent_gnts, struct grant,
- node);
+ BUG_ON(list_empty(&info->grants));
+ gnt_list_entry = list_first_entry(&info->grants, struct grant, node);
list_del(&gnt_list_entry->node);
if (gnt_list_entry->gref != GRANT_INVALID_REF) {
/* Assign a gref to this page */
gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
BUG_ON(gnt_list_entry->gref == -ENOSPC);
+ if (!info->feature_persistent) {
+ BUG_ON(!pfn);
+ gnt_list_entry->pfn = pfn;
+ }
buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn);
gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
info->xbdev->otherend_id,
ring_req->u.discard.flag = 0;
} else {
ring_req->u.rw.nr_segments = blk_rq_map_sg(req->q, req,
- info->sg);
+ info->shadow[id].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) {
+ for_each_sg(info->shadow[id].sg, sg, ring_req->u.rw.nr_segments, i) {
fsect = sg->offset >> 9;
lsect = fsect + (sg->length >> 9) - 1;
- gnt_list_entry = get_grant(&gref_head, info);
+ gnt_list_entry = get_grant(&gref_head, page_to_pfn(sg_page(sg)), info);
ref = gnt_list_entry->gref;
info->shadow[id].grants_used[i] = gnt_list_entry;
- if (rq_data_dir(req)) {
+ if (rq_data_dir(req) && info->feature_persistent) {
char *bvec_data;
void *shared_data;
blk_stop_queue(info->rq);
/* Remove all persistent grants */
- if (!list_empty(&info->persistent_gnts)) {
+ if (!list_empty(&info->grants)) {
list_for_each_entry_safe(persistent_gnt, n,
- &info->persistent_gnts, node) {
+ &info->grants, node) {
list_del(&persistent_gnt->node);
if (persistent_gnt->gref != GRANT_INVALID_REF) {
gnttab_end_foreign_access(persistent_gnt->gref,
0, 0UL);
info->persistent_gnts_c--;
}
- __free_page(pfn_to_page(persistent_gnt->pfn));
+ if (info->feature_persistent)
+ __free_page(pfn_to_page(persistent_gnt->pfn));
kfree(persistent_gnt);
}
}
struct blkif_response *bret)
{
int i = 0;
- struct bio_vec *bvec;
- struct req_iterator iter;
- unsigned long flags;
+ struct scatterlist *sg;
char *bvec_data;
void *shared_data;
- unsigned int offset = 0;
+ int nseg;
+
+ nseg = s->req.u.rw.nr_segments;
- if (bret->operation == BLKIF_OP_READ) {
+ if (bret->operation == BLKIF_OP_READ && info->feature_persistent) {
/*
* Copy the data received from the backend into the bvec.
* Since bv_offset can be different than 0, and bv_len different
* than PAGE_SIZE, we have to keep track of the current offset,
* to be sure we are copying the data from the right shared page.
*/
- rq_for_each_segment(bvec, s->request, iter) {
- 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);
+ for_each_sg(s->sg, sg, nseg, i) {
+ BUG_ON(sg->offset + sg->length > PAGE_SIZE);
shared_data = kmap_atomic(
pfn_to_page(s->grants_used[i]->pfn));
- bvec_data = bvec_kmap_irq(bvec, &flags);
- memcpy(bvec_data, shared_data + bvec->bv_offset,
- bvec->bv_len);
- bvec_kunmap_irq(bvec_data, &flags);
+ bvec_data = kmap_atomic(sg_page(sg));
+ memcpy(bvec_data + sg->offset,
+ shared_data + sg->offset,
+ sg->length);
+ kunmap_atomic(bvec_data);
kunmap_atomic(shared_data);
- offset = bvec->bv_offset + bvec->bv_len;
}
}
/* Add the persistent grant into the list of free grants */
- for (i = 0; i < s->req.u.rw.nr_segments; i++) {
- list_add(&s->grants_used[i]->node, &info->persistent_gnts);
- info->persistent_gnts_c++;
+ for (i = 0; i < nseg; i++) {
+ if (gnttab_query_foreign_access(s->grants_used[i]->gref)) {
+ /*
+ * If the grant is still mapped by the backend (the
+ * backend has chosen to make this grant persistent)
+ * we add it at the head of the list, so it will be
+ * reused first.
+ */
+ if (!info->feature_persistent)
+ pr_alert_ratelimited("backed has not unmapped grant: %u\n",
+ s->grants_used[i]->gref);
+ list_add(&s->grants_used[i]->node, &info->grants);
+ info->persistent_gnts_c++;
+ } else {
+ /*
+ * If the grant is not mapped by the backend we end the
+ * foreign access and add it to the tail of the list,
+ * so it will not be picked again unless we run out of
+ * persistent grants.
+ */
+ gnttab_end_foreign_access(s->grants_used[i]->gref, 0, 0UL);
+ s->grants_used[i]->gref = GRANT_INVALID_REF;
+ list_add_tail(&s->grants_used[i]->node, &info->grants);
+ }
}
}
struct blkfront_info *info)
{
struct blkif_sring *sring;
- int err;
+ int err, i;
info->ring_ref = GRANT_INVALID_REF;
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;
+ for (i = 0; i < BLK_RING_SIZE; i++)
+ sg_init_table(info->shadow[i].sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
if (err < 0) {
spin_lock_init(&info->io_lock);
info->xbdev = dev;
info->vdevice = vdevice;
- INIT_LIST_HEAD(&info->persistent_gnts);
+ INIT_LIST_HEAD(&info->grants);
info->persistent_gnts_c = 0;
info->connected = BLKIF_STATE_DISCONNECTED;
INIT_WORK(&info->work, blkif_restart_queue);
int i;
struct blkif_request *req;
struct blk_shadow *copy;
- int j;
+ unsigned int persistent;
+ int j, rc;
/* 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;
+ /* Check if the backend supports persistent grants */
+ rc = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-persistent", "%u", &persistent,
+ NULL);
+ if (rc)
+ info->feature_persistent = 0;
+ else
+ info->feature_persistent = persistent;
+
+ /* Allocate memory for grants */
+ rc = fill_grant_buffer(info, BLK_RING_SIZE *
+ BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ if (rc) {
+ xenbus_dev_fatal(info->xbdev, rc, "setting grant buffer failed");
+ kfree(copy);
+ return rc;
+ }
+
/* Stage 3: Find pending requests and requeue them. */
for (i = 0; i < BLK_RING_SIZE; i++) {
/* Not in use? */
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;
}
sectors);
set_capacity(info->gd, sectors);
revalidate_disk(info->gd);
+ return;
- /* fall through */
case BLKIF_STATE_SUSPENDED:
+ /*
+ * If we are recovering from suspension, we need to wait
+ * for the backend to announce it's features before
+ * reconnecting, we need to know if the backend supports
+ * persistent grants.
+ */
+ blkif_recover(info);
return;
default:
else
info->feature_persistent = persistent;
+ /* Allocate memory for grants */
+ err = fill_grant_buffer(info, BLK_RING_SIZE *
+ BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ if (err) {
+ xenbus_dev_fatal(info->xbdev, err, "setting grant buffer failed");
+ return;
+ }
+
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
if (err) {
xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
case XenbusStateReconfiguring:
case XenbusStateReconfigured:
case XenbusStateUnknown:
- case XenbusStateClosed:
break;
case XenbusStateConnected:
blkfront_connect(info);
break;
+ case XenbusStateClosed:
+ if (dev->state == XenbusStateClosed)
+ break;
+ /* Missed the backend's Closing state -- fallthrough */
case XenbusStateClosing:
blkfront_closing(info);
break;
projects / GitHub / mt8127 / android_kernel_alcatel_ttab.git / blobdiff