#include <linux/interrupt.h>
#include <linux/blkdev.h>
+#include <linux/blk-mq.h>
#include <linux/hdreg.h>
#include <linux/cdrom.h>
#include <linux/module.h>
struct grant {
grant_ref_t gref;
- unsigned long pfn;
+ struct page *page;
struct list_head node;
};
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 scatterlist *sg;
+ unsigned int num_sg;
+};
+
+struct split_bio {
+ struct bio *bio;
+ atomic_t pending;
};
static DEFINE_MUTEX(blkfront_mutex);
static const struct block_device_operations xlvbd_block_fops;
-#define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
+/*
+ * 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;
+module_param_named(max, xen_blkif_max_segments, int, S_IRUGO);
+MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests (default is 32)");
+
+/*
+ * Maximum order of pages to be used for the shared ring between front and
+ * backend, 4KB page granularity is used.
+ */
+static unsigned int xen_blkif_max_ring_order;
+module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, S_IRUGO);
+MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring");
+
+#define BLK_RING_SIZE(info) \
+ __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * (info)->nr_ring_pages)
+
+#define BLK_MAX_RING_SIZE \
+ __CONST_RING_SIZE(blkif, XEN_PAGE_SIZE * XENBUS_MAX_RING_GRANTS)
+
+/*
+ * ring-ref%i i=(-1UL) would take 11 characters + 'ring-ref' is 8, so 19
+ * characters are enough. Define to 20 to keep consist with backend.
+ */
+#define RINGREF_NAME_LEN (20)
/*
* We have one of these per vbd, whether ide, scsi or 'other'. They
int vdevice;
blkif_vdev_t handle;
enum blkif_state connected;
- int ring_ref;
+ int ring_ref[XENBUS_MAX_RING_GRANTS];
+ unsigned int nr_ring_pages;
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 blk_shadow shadow[BLK_MAX_RING_SIZE];
+ struct list_head grants;
+ struct list_head indirect_pages;
unsigned int persistent_gnts_c;
unsigned long shadow_free;
unsigned int feature_flush;
- unsigned int flush_op;
unsigned int feature_discard:1;
unsigned int feature_secdiscard:1;
unsigned int discard_granularity;
unsigned int discard_alignment;
unsigned int feature_persistent:1;
+ /* Number of 4KB segments handled */
+ unsigned int max_indirect_segments;
int is_ready;
+ struct blk_mq_tag_set tag_set;
};
static unsigned int nr_minors;
static unsigned long *minors;
static DEFINE_SPINLOCK(minor_lock);
-#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
- (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
#define GRANT_INVALID_REF 0
#define PARTS_PER_DISK 16
#define DEV_NAME "xvd" /* name in /dev */
+/*
+ * Grants are always the same size as a Xen page (i.e 4KB).
+ * A physical segment is always the same size as a Linux page.
+ * Number of grants per physical segment
+ */
+#define GRANTS_PER_PSEG (PAGE_SIZE / XEN_PAGE_SIZE)
+
+#define GRANTS_PER_INDIRECT_FRAME \
+ (XEN_PAGE_SIZE / sizeof(struct blkif_request_segment))
+
+#define PSEGS_PER_INDIRECT_FRAME \
+ (GRANTS_INDIRECT_FRAME / GRANTS_PSEGS)
+
+#define INDIRECT_GREFS(_grants) \
+ DIV_ROUND_UP(_grants, GRANTS_PER_INDIRECT_FRAME)
+
+#define GREFS(_psegs) ((_psegs) * GRANTS_PER_PSEG)
+
+static int blkfront_setup_indirect(struct blkfront_info *info);
+static int blkfront_gather_backend_features(struct blkfront_info *info);
+
static int get_id_from_freelist(struct blkfront_info *info)
{
unsigned long free = info->shadow_free;
- BUG_ON(free >= BLK_RING_SIZE);
+ BUG_ON(free >= BLK_RING_SIZE(info));
info->shadow_free = info->shadow[free].req.u.rw.id;
info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
return free;
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->page = 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(gnt_list_entry->page);
kfree(gnt_list_entry);
i--;
}
return -ENOMEM;
}
-static struct grant *get_grant(grant_ref_t *gref_head,
- struct blkfront_info *info)
+static struct grant *get_free_grant(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) {
+ if (gnt_list_entry->gref != GRANT_INVALID_REF)
info->persistent_gnts_c--;
+
+ return gnt_list_entry;
+}
+
+static inline void grant_foreign_access(const struct grant *gnt_list_entry,
+ const struct blkfront_info *info)
+{
+ gnttab_page_grant_foreign_access_ref_one(gnt_list_entry->gref,
+ info->xbdev->otherend_id,
+ gnt_list_entry->page,
+ 0);
+}
+
+static struct grant *get_grant(grant_ref_t *gref_head,
+ unsigned long gfn,
+ struct blkfront_info *info)
+{
+ struct grant *gnt_list_entry = get_free_grant(info);
+
+ if (gnt_list_entry->gref != GRANT_INVALID_REF)
return gnt_list_entry;
+
+ /* 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)
+ grant_foreign_access(gnt_list_entry, info);
+ else {
+ /* Grant access to the GFN passed by the caller */
+ gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
+ info->xbdev->otherend_id,
+ gfn, 0);
}
+ return gnt_list_entry;
+}
+
+static struct grant *get_indirect_grant(grant_ref_t *gref_head,
+ struct blkfront_info *info)
+{
+ struct grant *gnt_list_entry = get_free_grant(info);
+
+ if (gnt_list_entry->gref != GRANT_INVALID_REF)
+ return gnt_list_entry;
+
/* Assign a gref to this page */
gnt_list_entry->gref = gnttab_claim_grant_reference(gref_head);
BUG_ON(gnt_list_entry->gref == -ENOSPC);
- buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn);
- gnttab_grant_foreign_access_ref(gnt_list_entry->gref,
- info->xbdev->otherend_id,
- buffer_mfn, 0);
+ if (!info->feature_persistent) {
+ struct page *indirect_page;
+
+ /* Fetch a pre-allocated page to use for indirect grefs */
+ BUG_ON(list_empty(&info->indirect_pages));
+ indirect_page = list_first_entry(&info->indirect_pages,
+ struct page, lru);
+ list_del(&indirect_page->lru);
+ gnt_list_entry->page = indirect_page;
+ }
+ grant_foreign_access(gnt_list_entry, info);
+
return gnt_list_entry;
}
return 0;
}
-/*
- * Generate a Xen blkfront IO request from a blk layer request. Reads
- * and writes are handled as expected.
- *
- * @req: a request struct
- */
-static int blkif_queue_request(struct request *req)
+static int blkif_queue_discard_req(struct request *req)
{
struct blkfront_info *info = req->rq_disk->private_data;
struct blkif_request *ring_req;
unsigned long id;
+
+ /* Fill out a communications ring structure. */
+ ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
+ id = get_id_from_freelist(info);
+ info->shadow[id].request = req;
+
+ 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;
+
+ info->ring.req_prod_pvt++;
+
+ /* Keep a private copy so we can reissue requests when recovering. */
+ info->shadow[id].req = *ring_req;
+
+ return 0;
+}
+
+struct setup_rw_req {
+ unsigned int grant_idx;
+ struct blkif_request_segment *segments;
+ struct blkfront_info *info;
+ struct blkif_request *ring_req;
+ grant_ref_t gref_head;
+ unsigned int id;
+ /* Only used when persistent grant is used and it's a read request */
+ bool need_copy;
+ unsigned int bvec_off;
+ char *bvec_data;
+};
+
+static void blkif_setup_rw_req_grant(unsigned long gfn, unsigned int offset,
+ unsigned int len, void *data)
+{
+ struct setup_rw_req *setup = data;
+ int n, ref;
+ struct grant *gnt_list_entry;
unsigned int fsect, lsect;
- int i, ref;
+ /* Convenient aliases */
+ unsigned int grant_idx = setup->grant_idx;
+ struct blkif_request *ring_req = setup->ring_req;
+ struct blkfront_info *info = setup->info;
+ struct blk_shadow *shadow = &info->shadow[setup->id];
+
+ if ((ring_req->operation == BLKIF_OP_INDIRECT) &&
+ (grant_idx % GRANTS_PER_INDIRECT_FRAME == 0)) {
+ if (setup->segments)
+ kunmap_atomic(setup->segments);
+
+ n = grant_idx / GRANTS_PER_INDIRECT_FRAME;
+ gnt_list_entry = get_indirect_grant(&setup->gref_head, info);
+ shadow->indirect_grants[n] = gnt_list_entry;
+ setup->segments = kmap_atomic(gnt_list_entry->page);
+ ring_req->u.indirect.indirect_grefs[n] = gnt_list_entry->gref;
+ }
+
+ gnt_list_entry = get_grant(&setup->gref_head, gfn, info);
+ ref = gnt_list_entry->gref;
+ shadow->grants_used[grant_idx] = gnt_list_entry;
+
+ if (setup->need_copy) {
+ void *shared_data;
+
+ shared_data = kmap_atomic(gnt_list_entry->page);
+ /*
+ * this does not wipe data stored outside the
+ * range sg->offset..sg->offset+sg->length.
+ * Therefore, blkback *could* see data from
+ * previous requests. This is OK as long as
+ * persistent grants are shared with just one
+ * domain. It may need refactoring if this
+ * changes
+ */
+ memcpy(shared_data + offset,
+ setup->bvec_data + setup->bvec_off,
+ len);
+
+ kunmap_atomic(shared_data);
+ setup->bvec_off += len;
+ }
+
+ fsect = offset >> 9;
+ lsect = fsect + (len >> 9) - 1;
+ if (ring_req->operation != BLKIF_OP_INDIRECT) {
+ ring_req->u.rw.seg[grant_idx] =
+ (struct blkif_request_segment) {
+ .gref = ref,
+ .first_sect = fsect,
+ .last_sect = lsect };
+ } else {
+ setup->segments[grant_idx % GRANTS_PER_INDIRECT_FRAME] =
+ (struct blkif_request_segment) {
+ .gref = ref,
+ .first_sect = fsect,
+ .last_sect = lsect };
+ }
+
+ (setup->grant_idx)++;
+}
+
+static int blkif_queue_rw_req(struct request *req)
+{
+ struct blkfront_info *info = req->rq_disk->private_data;
+ struct blkif_request *ring_req;
+ unsigned long id;
+ int i;
+ struct setup_rw_req setup = {
+ .grant_idx = 0,
+ .segments = NULL,
+ .info = info,
+ .need_copy = rq_data_dir(req) && info->feature_persistent,
+ };
/*
* Used to store if we are able to queue the request by just using
* as there are not sufficiently many free.
*/
bool new_persistent_gnts;
- grant_ref_t gref_head;
- struct grant *gnt_list_entry = NULL;
struct scatterlist *sg;
+ int num_sg, max_grefs, num_grant;
- if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
- return 1;
+ max_grefs = req->nr_phys_segments * GRANTS_PER_PSEG;
+ if (max_grefs > BLKIF_MAX_SEGMENTS_PER_REQUEST)
+ /*
+ * If we are using indirect segments we need to account
+ * for the indirect grefs used in the request.
+ */
+ max_grefs += INDIRECT_GREFS(max_grefs);
- /* Check if we have enought grants to allocate a requests */
- if (info->persistent_gnts_c < 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,
- &gref_head) < 0) {
+ max_grefs - info->persistent_gnts_c,
+ &setup.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;
+ BUG_ON(info->max_indirect_segments == 0 &&
+ GREFS(req->nr_phys_segments) > BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ BUG_ON(info->max_indirect_segments &&
+ GREFS(req->nr_phys_segments) > info->max_indirect_segments);
- ring_req->operation = rq_data_dir(req) ?
- BLKIF_OP_WRITE : BLKIF_OP_READ;
+ num_sg = blk_rq_map_sg(req->q, req, info->shadow[id].sg);
+ num_grant = 0;
+ /* Calculate the number of grant used */
+ for_each_sg(info->shadow[id].sg, sg, num_sg, i)
+ num_grant += gnttab_count_grant(sg->offset, sg->length);
- if (req->cmd_flags & (REQ_FLUSH | REQ_FUA)) {
+ ring_req->u.rw.id = id;
+ info->shadow[id].num_sg = num_sg;
+ if (num_grant > BLKIF_MAX_SEGMENTS_PER_REQUEST) {
/*
- * 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.)
+ * The indirect operation can only be a BLKIF_OP_READ or
+ * BLKIF_OP_WRITE
*/
- 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);
- if ((req->cmd_flags & REQ_SECURE) && info->feature_secdiscard)
- ring_req->u.discard.flag = BLKIF_DISCARD_SECURE;
- else
- ring_req->u.discard.flag = 0;
+ 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 = num_grant;
} 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) {
- fsect = sg->offset >> 9;
- lsect = fsect + (sg->length >> 9) - 1;
-
- gnt_list_entry = get_grant(&gref_head, info);
- ref = gnt_list_entry->gref;
-
- info->shadow[id].grants_used[i] = gnt_list_entry;
-
- if (rq_data_dir(req)) {
- char *bvec_data;
- void *shared_data;
-
- BUG_ON(sg->offset + sg->length > PAGE_SIZE);
+ 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.)
+ */
+ switch (info->feature_flush &
+ ((REQ_FLUSH|REQ_FUA))) {
+ case REQ_FLUSH|REQ_FUA:
+ ring_req->operation =
+ BLKIF_OP_WRITE_BARRIER;
+ break;
+ case REQ_FLUSH:
+ ring_req->operation =
+ BLKIF_OP_FLUSH_DISKCACHE;
+ break;
+ default:
+ ring_req->operation = 0;
+ }
+ }
+ ring_req->u.rw.nr_segments = num_grant;
+ }
- shared_data = kmap_atomic(
- pfn_to_page(gnt_list_entry->pfn));
- bvec_data = kmap_atomic(sg_page(sg));
+ setup.ring_req = ring_req;
+ setup.id = id;
+ for_each_sg(info->shadow[id].sg, sg, num_sg, i) {
+ BUG_ON(sg->offset + sg->length > PAGE_SIZE);
- /*
- * this does not wipe data stored outside the
- * range sg->offset..sg->offset+sg->length.
- * Therefore, blkback *could* see data from
- * previous requests. This is OK as long as
- * persistent grants are shared with just one
- * domain. It may need refactoring if this
- * changes
- */
- memcpy(shared_data + sg->offset,
- bvec_data + sg->offset,
- sg->length);
+ if (setup.need_copy) {
+ setup.bvec_off = sg->offset;
+ setup.bvec_data = kmap_atomic(sg_page(sg));
+ }
- kunmap_atomic(bvec_data);
- kunmap_atomic(shared_data);
- }
+ gnttab_foreach_grant_in_range(sg_page(sg),
+ sg->offset,
+ sg->length,
+ blkif_setup_rw_req_grant,
+ &setup);
- ring_req->u.rw.seg[i] =
- (struct blkif_request_segment) {
- .gref = ref,
- .first_sect = fsect,
- .last_sect = lsect };
- }
+ if (setup.need_copy)
+ kunmap_atomic(setup.bvec_data);
}
+ if (setup.segments)
+ kunmap_atomic(setup.segments);
info->ring.req_prod_pvt++;
info->shadow[id].req = *ring_req;
if (new_persistent_gnts)
- gnttab_free_grant_references(gref_head);
+ gnttab_free_grant_references(setup.gref_head);
return 0;
}
+/*
+ * Generate a Xen blkfront IO request from a blk layer request. Reads
+ * and writes are handled as expected.
+ *
+ * @req: a request struct
+ */
+static int blkif_queue_request(struct request *req)
+{
+ struct blkfront_info *info = req->rq_disk->private_data;
+
+ if (unlikely(info->connected != BLKIF_STATE_CONNECTED))
+ return 1;
+
+ if (unlikely(req->cmd_flags & (REQ_DISCARD | REQ_SECURE)))
+ return blkif_queue_discard_req(req);
+ else
+ return blkif_queue_rw_req(req);
+}
static inline void flush_requests(struct blkfront_info *info)
{
notify_remote_via_irq(info->irq);
}
-/*
- * do_blkif_request
- * read a block; request is in a request queue
- */
-static void do_blkif_request(struct request_queue *rq)
+static inline bool blkif_request_flush_invalid(struct request *req,
+ struct blkfront_info *info)
{
- struct blkfront_info *info = NULL;
- struct request *req;
- int queued;
-
- pr_debug("Entered do_blkif_request\n");
+ return ((req->cmd_type != REQ_TYPE_FS) ||
+ ((req->cmd_flags & REQ_FLUSH) &&
+ !(info->feature_flush & REQ_FLUSH)) ||
+ ((req->cmd_flags & REQ_FUA) &&
+ !(info->feature_flush & REQ_FUA)));
+}
- queued = 0;
+static int blkif_queue_rq(struct blk_mq_hw_ctx *hctx,
+ const struct blk_mq_queue_data *qd)
+{
+ struct blkfront_info *info = qd->rq->rq_disk->private_data;
- while ((req = blk_peek_request(rq)) != NULL) {
- info = req->rq_disk->private_data;
+ blk_mq_start_request(qd->rq);
+ spin_lock_irq(&info->io_lock);
+ if (RING_FULL(&info->ring))
+ goto out_busy;
- if (RING_FULL(&info->ring))
- goto wait;
+ if (blkif_request_flush_invalid(qd->rq, info))
+ goto out_err;
- blk_start_request(req);
+ if (blkif_queue_request(qd->rq))
+ goto out_busy;
- if ((req->cmd_type != REQ_TYPE_FS) ||
- ((req->cmd_flags & (REQ_FLUSH | REQ_FUA)) &&
- !info->flush_op)) {
- __blk_end_request_all(req, -EIO);
- continue;
- }
-
- pr_debug("do_blk_req %p: cmd %p, sec %lx, "
- "(%u/%u) buffer:%p [%s]\n",
- req, req->cmd, (unsigned long)blk_rq_pos(req),
- blk_rq_cur_sectors(req), blk_rq_sectors(req),
- req->buffer, rq_data_dir(req) ? "write" : "read");
-
- if (blkif_queue_request(req)) {
- blk_requeue_request(rq, req);
-wait:
- /* Avoid pointless unplugs. */
- blk_stop_queue(rq);
- break;
- }
+ flush_requests(info);
+ spin_unlock_irq(&info->io_lock);
+ return BLK_MQ_RQ_QUEUE_OK;
- queued++;
- }
+out_err:
+ spin_unlock_irq(&info->io_lock);
+ return BLK_MQ_RQ_QUEUE_ERROR;
- if (queued != 0)
- flush_requests(info);
+out_busy:
+ spin_unlock_irq(&info->io_lock);
+ blk_mq_stop_hw_queue(hctx);
+ return BLK_MQ_RQ_QUEUE_BUSY;
}
-static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
+static struct blk_mq_ops blkfront_mq_ops = {
+ .queue_rq = blkif_queue_rq,
+ .map_queue = blk_mq_map_queue,
+};
+
+static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
+ unsigned int physical_sector_size,
+ unsigned int segments)
{
struct request_queue *rq;
struct blkfront_info *info = gd->private_data;
- rq = blk_init_queue(do_blkif_request, &info->io_lock);
- if (rq == NULL)
+ memset(&info->tag_set, 0, sizeof(info->tag_set));
+ info->tag_set.ops = &blkfront_mq_ops;
+ info->tag_set.nr_hw_queues = 1;
+ info->tag_set.queue_depth = BLK_RING_SIZE(info);
+ info->tag_set.numa_node = NUMA_NO_NODE;
+ info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+ info->tag_set.cmd_size = 0;
+ info->tag_set.driver_data = info;
+
+ if (blk_mq_alloc_tag_set(&info->tag_set))
return -1;
+ rq = blk_mq_init_queue(&info->tag_set);
+ if (IS_ERR(rq)) {
+ blk_mq_free_tag_set(&info->tag_set);
+ return -1;
+ }
queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
/* 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);
+ blk_queue_physical_block_size(rq, physical_sector_size);
+ blk_queue_max_hw_sectors(rq, (segments * XEN_PAGE_SIZE) / 512);
/* Each segment in a request is up to an aligned page in size. */
blk_queue_segment_boundary(rq, PAGE_SIZE - 1);
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 / GRANTS_PER_PSEG);
/* Make sure buffer addresses are sector-aligned. */
blk_queue_dma_alignment(rq, 511);
return 0;
}
+static const char *flush_info(unsigned int feature_flush)
+{
+ switch (feature_flush & ((REQ_FLUSH | REQ_FUA))) {
+ case REQ_FLUSH|REQ_FUA:
+ return "barrier: enabled;";
+ case REQ_FLUSH:
+ return "flush diskcache: enabled;";
+ default:
+ return "barrier or flush: disabled;";
+ }
+}
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",
- 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" : "");
+ pr_info("blkfront: %s: %s %s %s %s %s\n",
+ info->gd->disk_name, flush_info(info->feature_flush),
+ "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)
static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
struct blkfront_info *info,
- u16 vdisk_info, u16 sector_size)
+ u16 vdisk_info, u16 sector_size,
+ unsigned int physical_sector_size)
{
struct gendisk *gd;
int nr_minors = 1;
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, physical_sector_size,
+ info->max_indirect_segments ? :
+ BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
del_gendisk(gd);
goto release;
}
static void xlvbd_release_gendisk(struct blkfront_info *info)
{
unsigned int minor, nr_minors;
- unsigned long flags;
if (info->rq == NULL)
return;
- spin_lock_irqsave(&info->io_lock, flags);
-
/* No more blkif_request(). */
- blk_stop_queue(info->rq);
+ blk_mq_stop_hw_queues(info->rq);
/* No more gnttab callback work. */
gnttab_cancel_free_callback(&info->callback);
- spin_unlock_irqrestore(&info->io_lock, flags);
/* Flush gnttab callback work. Must be done with no locks held. */
flush_work(&info->work);
xlbd_release_minors(minor, nr_minors);
blk_cleanup_queue(info->rq);
+ blk_mq_free_tag_set(&info->tag_set);
info->rq = NULL;
put_disk(info->gd);
info->gd = NULL;
}
+/* Must be called with io_lock holded */
static void kick_pending_request_queues(struct blkfront_info *info)
{
- if (!RING_FULL(&info->ring)) {
- /* Re-enable calldowns. */
- blk_start_queue(info->rq);
- /* Kick things off immediately. */
- do_blkif_request(info->rq);
- }
+ if (!RING_FULL(&info->ring))
+ blk_mq_start_stopped_hw_queues(info->rq, true);
}
static void blkif_restart_queue(struct work_struct *work)
{
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);
BLKIF_STATE_SUSPENDED : BLKIF_STATE_DISCONNECTED;
/* No more blkif_request(). */
if (info->rq)
- blk_stop_queue(info->rq);
+ blk_mq_stop_hw_queues(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(persistent_gnt->page);
kfree(persistent_gnt);
}
}
BUG_ON(info->persistent_gnts_c != 0);
+ /*
+ * Remove indirect pages, this only happens when using indirect
+ * descriptors but not persistent grants
+ */
+ if (!list_empty(&info->indirect_pages)) {
+ struct page *indirect_page, *n;
+
+ BUG_ON(info->feature_persistent);
+ list_for_each_entry_safe(indirect_page, n, &info->indirect_pages, lru) {
+ list_del(&indirect_page->lru);
+ __free_page(indirect_page);
+ }
+ }
+
+ for (i = 0; i < BLK_RING_SIZE(info); 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);
+ if (info->feature_persistent)
+ __free_page(persistent_gnt->page);
+ 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(persistent_gnt->page);
+ 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;
+ kfree(info->shadow[i].sg);
+ info->shadow[i].sg = NULL;
+ }
+
/* No more gnttab callback work. */
gnttab_cancel_free_callback(&info->callback);
spin_unlock_irq(&info->io_lock);
flush_work(&info->work);
/* Free resources associated with old device channel. */
- if (info->ring_ref != GRANT_INVALID_REF) {
- gnttab_end_foreign_access(info->ring_ref, 0,
- (unsigned long)info->ring.sring);
- info->ring_ref = GRANT_INVALID_REF;
- info->ring.sring = NULL;
+ for (i = 0; i < info->nr_ring_pages; i++) {
+ if (info->ring_ref[i] != GRANT_INVALID_REF) {
+ gnttab_end_foreign_access(info->ring_ref[i], 0, 0);
+ info->ring_ref[i] = GRANT_INVALID_REF;
+ }
}
+ free_pages((unsigned long)info->ring.sring, get_order(info->nr_ring_pages * PAGE_SIZE));
+ info->ring.sring = NULL;
+
if (info->irq)
unbind_from_irqhandler(info->irq, info);
info->evtchn = info->irq = 0;
}
+struct copy_from_grant {
+ const struct blk_shadow *s;
+ unsigned int grant_idx;
+ unsigned int bvec_offset;
+ char *bvec_data;
+};
+
+static void blkif_copy_from_grant(unsigned long gfn, unsigned int offset,
+ unsigned int len, void *data)
+{
+ struct copy_from_grant *info = data;
+ char *shared_data;
+ /* Convenient aliases */
+ const struct blk_shadow *s = info->s;
+
+ shared_data = kmap_atomic(s->grants_used[info->grant_idx]->page);
+
+ memcpy(info->bvec_data + info->bvec_offset,
+ shared_data + offset, len);
+
+ info->bvec_offset += len;
+ info->grant_idx++;
+
+ kunmap_atomic(shared_data);
+}
+
static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
struct blkif_response *bret)
{
int i = 0;
- struct bio_vec *bvec;
- struct req_iterator iter;
- unsigned long flags;
- char *bvec_data;
- void *shared_data;
- unsigned int offset = 0;
-
- if (bret->operation == BLKIF_OP_READ) {
- /*
- * 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);
- 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);
- kunmap_atomic(shared_data);
- offset = bvec->bv_offset + bvec->bv_len;
+ struct scatterlist *sg;
+ int num_sg, num_grant;
+ struct copy_from_grant data = {
+ .s = s,
+ .grant_idx = 0,
+ };
+
+ num_grant = s->req.operation == BLKIF_OP_INDIRECT ?
+ s->req.u.indirect.nr_segments : s->req.u.rw.nr_segments;
+ num_sg = s->num_sg;
+
+ if (bret->operation == BLKIF_OP_READ && info->feature_persistent) {
+ for_each_sg(s->sg, sg, num_sg, i) {
+ BUG_ON(sg->offset + sg->length > PAGE_SIZE);
+
+ data.bvec_offset = sg->offset;
+ data.bvec_data = kmap_atomic(sg_page(sg));
+
+ gnttab_foreach_grant_in_range(sg_page(sg),
+ sg->offset,
+ sg->length,
+ blkif_copy_from_grant,
+ &data);
+
+ kunmap_atomic(data.bvec_data);
}
}
/* 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 < num_grant; 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);
+ }
+ }
+ if (s->req.operation == BLKIF_OP_INDIRECT) {
+ for (i = 0; i < INDIRECT_GREFS(num_grant); i++) {
+ if (gnttab_query_foreign_access(s->indirect_grants[i]->gref)) {
+ if (!info->feature_persistent)
+ pr_alert_ratelimited("backed has not unmapped grant: %u\n",
+ s->indirect_grants[i]->gref);
+ list_add(&s->indirect_grants[i]->node, &info->grants);
+ info->persistent_gnts_c++;
+ } else {
+ struct page *indirect_page;
+
+ gnttab_end_foreign_access(s->indirect_grants[i]->gref, 0, 0UL);
+ /*
+ * Add the used indirect page back to the list of
+ * available pages for indirect grefs.
+ */
+ if (!info->feature_persistent) {
+ indirect_page = s->indirect_grants[i]->page;
+ list_add(&indirect_page->lru, &info->indirect_pages);
+ }
+ s->indirect_grants[i]->gref = GRANT_INVALID_REF;
+ list_add_tail(&s->indirect_grants[i]->node, &info->grants);
+ }
+ }
}
}
* never have given to it (we stamp it up to BLK_RING_SIZE -
* look in get_id_from_freelist.
*/
- if (id >= BLK_RING_SIZE) {
+ if (id >= BLK_RING_SIZE(info)) {
WARN(1, "%s: response to %s has incorrect id (%ld)\n",
info->gd->disk_name, op_name(bret->operation), id);
/* We can't safely get the 'struct request' as
queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
}
- __blk_end_request_all(req, error);
+ blk_mq_complete_request(req, error);
break;
case BLKIF_OP_FLUSH_DISKCACHE:
case BLKIF_OP_WRITE_BARRIER:
if (error == -EOPNOTSUPP)
error = 0;
info->feature_flush = 0;
- info->flush_op = 0;
xlvbd_flush(info);
}
/* fall through */
dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
"request: %x\n", bret->status);
- __blk_end_request_all(req, error);
+ blk_mq_complete_request(req, error);
break;
default:
BUG();
struct blkfront_info *info)
{
struct blkif_sring *sring;
- int err;
+ int err, i;
+ unsigned long ring_size = info->nr_ring_pages * XEN_PAGE_SIZE;
+ grant_ref_t gref[XENBUS_MAX_RING_GRANTS];
- info->ring_ref = GRANT_INVALID_REF;
+ for (i = 0; i < info->nr_ring_pages; i++)
+ info->ring_ref[i] = GRANT_INVALID_REF;
- sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
+ sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH,
+ get_order(ring_size));
if (!sring) {
xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
return -ENOMEM;
}
SHARED_RING_INIT(sring);
- FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
+ FRONT_RING_INIT(&info->ring, sring, ring_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));
+ err = xenbus_grant_ring(dev, info->ring.sring, info->nr_ring_pages, gref);
if (err < 0) {
- free_page((unsigned long)sring);
+ free_pages((unsigned long)sring, get_order(ring_size));
info->ring.sring = NULL;
goto fail;
}
- info->ring_ref = err;
+ for (i = 0; i < info->nr_ring_pages; i++)
+ info->ring_ref[i] = gref[i];
err = xenbus_alloc_evtchn(dev, &info->evtchn);
if (err)
{
const char *message = NULL;
struct xenbus_transaction xbt;
- int err;
+ int err, i;
+ unsigned int max_page_order = 0;
+ unsigned int ring_page_order = 0;
+
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "max-ring-page-order", "%u", &max_page_order);
+ if (err != 1)
+ info->nr_ring_pages = 1;
+ else {
+ ring_page_order = min(xen_blkif_max_ring_order, max_page_order);
+ info->nr_ring_pages = 1 << ring_page_order;
+ }
/* Create shared ring, alloc event channel. */
err = setup_blkring(dev, info);
goto destroy_blkring;
}
- err = xenbus_printf(xbt, dev->nodename,
- "ring-ref", "%u", info->ring_ref);
- if (err) {
- message = "writing ring-ref";
- goto abort_transaction;
+ if (info->nr_ring_pages == 1) {
+ err = xenbus_printf(xbt, dev->nodename,
+ "ring-ref", "%u", info->ring_ref[0]);
+ if (err) {
+ message = "writing ring-ref";
+ goto abort_transaction;
+ }
+ } else {
+ err = xenbus_printf(xbt, dev->nodename,
+ "ring-page-order", "%u", ring_page_order);
+ if (err) {
+ message = "writing ring-page-order";
+ goto abort_transaction;
+ }
+
+ for (i = 0; i < info->nr_ring_pages; i++) {
+ char ring_ref_name[RINGREF_NAME_LEN];
+
+ snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i);
+ err = xenbus_printf(xbt, dev->nodename, ring_ref_name,
+ "%u", info->ring_ref[i]);
+ if (err) {
+ message = "writing ring-ref";
+ goto abort_transaction;
+ }
+ }
}
err = xenbus_printf(xbt, dev->nodename,
"event-channel", "%u", info->evtchn);
goto destroy_blkring;
}
+ for (i = 0; i < BLK_RING_SIZE(info); i++)
+ info->shadow[i].req.u.rw.id = i+1;
+ info->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff;
xenbus_switch_state(dev, XenbusStateInitialised);
return 0;
static int blkfront_probe(struct xenbus_device *dev,
const struct xenbus_device_id *id)
{
- int err, vdevice, i;
+ int err, vdevice;
struct blkfront_info *info;
/* FIXME: Use dynamic device id if this is not set. */
char *type;
int len;
/* no unplug has been done: do not hook devices != xen vbds */
- if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) {
+ if (xen_has_pv_and_legacy_disk_devices()) {
int major;
if (!VDEV_IS_EXTENDED(vdevice))
if (major != XENVBD_MAJOR) {
printk(KERN_INFO
"%s: HVM does not support vbd %d as xen block device\n",
- __FUNCTION__, vdevice);
+ __func__, vdevice);
return -ENODEV;
}
}
spin_lock_init(&info->io_lock);
info->xbdev = dev;
info->vdevice = vdevice;
- INIT_LIST_HEAD(&info->persistent_gnts);
+ INIT_LIST_HEAD(&info->grants);
+ INIT_LIST_HEAD(&info->indirect_pages);
info->persistent_gnts_c = 0;
info->connected = BLKIF_STATE_DISCONNECTED;
INIT_WORK(&info->work, blkif_restart_queue);
- for (i = 0; i < BLK_RING_SIZE; i++)
- info->shadow[i].req.u.rw.id = i+1;
- info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
-
/* Front end dir is a number, which is used as the id. */
info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
dev_set_drvdata(&dev->dev, info);
- err = talk_to_blkback(dev, info);
- if (err) {
- kfree(info);
- dev_set_drvdata(&dev->dev, NULL);
- return err;
- }
-
return 0;
}
+static void split_bio_end(struct bio *bio)
+{
+ struct split_bio *split_bio = bio->bi_private;
+
+ if (atomic_dec_and_test(&split_bio->pending)) {
+ split_bio->bio->bi_phys_segments = 0;
+ split_bio->bio->bi_error = bio->bi_error;
+ bio_endio(split_bio->bio);
+ 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),
/* Stage 2: Set up free list. */
memset(&info->shadow, 0, sizeof(info->shadow));
- for (i = 0; i < BLK_RING_SIZE; i++)
+ for (i = 0; i < BLK_RING_SIZE(info); i++)
info->shadow[i].req.u.rw.id = i+1;
info->shadow_free = info->ring.req_prod_pvt;
- info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
+ info->shadow[BLK_RING_SIZE(info)-1].req.u.rw.id = 0x0fffffff;
- /* Stage 3: Find pending requests and requeue them. */
- for (i = 0; i < BLK_RING_SIZE; i++) {
+ rc = blkfront_gather_backend_features(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(info); 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_end_request_all(copy[i].request, 0);
}
kfree(copy);
/* 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_mq_requeue_request(req);
+ }
spin_unlock_irq(&info->io_lock);
+ blk_mq_kick_requeue_list(info->rq);
+
+ 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 * XEN_PAGE_SIZE) >> 9;
+ size = min((unsigned int)(segs * XEN_PAGE_SIZE) >> 9,
+ (unsigned int)bio_sectors(bio) - offset);
+ cloned_bio = bio_clone(bio, GFP_NOIO);
+ BUG_ON(cloned_bio == NULL);
+ bio_trim(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;
}
static void blkfront_setup_discard(struct blkfront_info *info)
{
int err;
- char *type;
unsigned int discard_granularity;
unsigned int discard_alignment;
unsigned int discard_secure;
- type = xenbus_read(XBT_NIL, info->xbdev->otherend, "type", NULL);
- if (IS_ERR(type))
- return;
+ info->feature_discard = 1;
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "discard-granularity", "%u", &discard_granularity,
+ "discard-alignment", "%u", &discard_alignment,
+ NULL);
+ if (!err) {
+ info->discard_granularity = discard_granularity;
+ info->discard_alignment = discard_alignment;
+ }
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "discard-secure", "%d", &discard_secure,
+ NULL);
+ if (!err)
+ info->feature_secdiscard = !!discard_secure;
+}
- info->feature_secdiscard = 0;
- 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;
+static int blkfront_setup_indirect(struct blkfront_info *info)
+{
+ unsigned int psegs, grants;
+ int err, i;
+
+ if (info->max_indirect_segments == 0)
+ grants = BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ else
+ grants = info->max_indirect_segments;
+ psegs = grants / GRANTS_PER_PSEG;
+
+ err = fill_grant_buffer(info,
+ (grants + INDIRECT_GREFS(grants)) * BLK_RING_SIZE(info));
+ if (err)
+ goto out_of_memory;
+
+ if (!info->feature_persistent && info->max_indirect_segments) {
+ /*
+ * We are using indirect descriptors but not persistent
+ * grants, we need to allocate a set of pages that can be
+ * used for mapping indirect grefs
+ */
+ int num = INDIRECT_GREFS(grants) * BLK_RING_SIZE(info);
+
+ BUG_ON(!list_empty(&info->indirect_pages));
+ for (i = 0; i < num; i++) {
+ struct page *indirect_page = alloc_page(GFP_NOIO);
+ if (!indirect_page)
+ goto out_of_memory;
+ list_add(&indirect_page->lru, &info->indirect_pages);
}
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "discard-secure", "%d", &discard_secure,
- NULL);
- if (!err)
- info->feature_secdiscard = discard_secure;
+ }
+
+ for (i = 0; i < BLK_RING_SIZE(info); i++) {
+ info->shadow[i].grants_used = kzalloc(
+ sizeof(info->shadow[i].grants_used[0]) * grants,
+ GFP_NOIO);
+ info->shadow[i].sg = kzalloc(sizeof(info->shadow[i].sg[0]) * psegs, GFP_NOIO);
+ if (info->max_indirect_segments)
+ info->shadow[i].indirect_grants = kzalloc(
+ sizeof(info->shadow[i].indirect_grants[0]) *
+ INDIRECT_GREFS(grants),
+ GFP_NOIO);
+ if ((info->shadow[i].grants_used == NULL) ||
+ (info->shadow[i].sg == NULL) ||
+ (info->max_indirect_segments &&
+ (info->shadow[i].indirect_grants == NULL)))
+ goto out_of_memory;
+ sg_init_table(info->shadow[i].sg, psegs);
+ }
+
- } else if (strncmp(type, "file", 4) == 0)
- info->feature_discard = 1;
+ return 0;
- kfree(type);
+out_of_memory:
+ for (i = 0; i < BLK_RING_SIZE(info); i++) {
+ kfree(info->shadow[i].grants_used);
+ info->shadow[i].grants_used = NULL;
+ kfree(info->shadow[i].sg);
+ info->shadow[i].sg = NULL;
+ kfree(info->shadow[i].indirect_grants);
+ info->shadow[i].indirect_grants = NULL;
+ }
+ if (!list_empty(&info->indirect_pages)) {
+ struct page *indirect_page, *n;
+ list_for_each_entry_safe(indirect_page, n, &info->indirect_pages, lru) {
+ list_del(&indirect_page->lru);
+ __free_page(indirect_page);
+ }
+ }
+ return -ENOMEM;
+}
+
+/*
+ * Gather all backend feature-*
+ */
+static int blkfront_gather_backend_features(struct blkfront_info *info)
+{
+ int err;
+ int barrier, flush, discard, persistent;
+ unsigned int indirect_segments;
+
+ info->feature_flush = 0;
+
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-barrier", "%d", &barrier,
+ NULL);
+
+ /*
+ * If there's no "feature-barrier" defined, then it means
+ * we're dealing with a very old backend which writes
+ * synchronously; nothing to do.
+ *
+ * If there are barriers, then we use flush.
+ */
+ if (!err && barrier)
+ info->feature_flush = REQ_FLUSH | REQ_FUA;
+ /*
+ * And if there is "feature-flush-cache" use that above
+ * barriers.
+ */
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-flush-cache", "%d", &flush,
+ NULL);
+
+ if (!err && flush)
+ info->feature_flush = REQ_FLUSH;
+
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-discard", "%d", &discard,
+ NULL);
+
+ if (!err && discard)
+ blkfront_setup_discard(info);
+
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-persistent", "%u", &persistent,
+ NULL);
+ if (err)
+ info->feature_persistent = 0;
+ else
+ info->feature_persistent = persistent;
+
+ err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
+ "feature-max-indirect-segments", "%u", &indirect_segments,
+ NULL);
+ if (err)
+ info->max_indirect_segments = 0;
+ else
+ info->max_indirect_segments = min(indirect_segments,
+ xen_blkif_max_segments);
+
+ return blkfront_setup_indirect(info);
}
/*
{
unsigned long long sectors;
unsigned long sector_size;
+ unsigned int physical_sector_size;
unsigned int binfo;
int err;
- int barrier, flush, discard, persistent;
switch (info->connected) {
case BLKIF_STATE_CONNECTED:
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:
return;
}
- info->feature_flush = 0;
- info->flush_op = 0;
-
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "feature-barrier", "%d", &barrier,
- NULL);
-
- /*
- * If there's no "feature-barrier" defined, then it means
- * we're dealing with a very old backend which writes
- * synchronously; nothing to do.
- *
- * If there are barriers, then we use flush.
- */
- if (!err && barrier) {
- info->feature_flush = REQ_FLUSH | REQ_FUA;
- info->flush_op = BLKIF_OP_WRITE_BARRIER;
- }
/*
- * And if there is "feature-flush-cache" use that above
- * barriers.
+ * physcial-sector-size is a newer field, so old backends may not
+ * provide this. Assume physical sector size to be the same as
+ * sector_size in that case.
*/
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "feature-flush-cache", "%d", &flush,
- NULL);
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "physical-sector-size", "%u", &physical_sector_size);
+ if (err != 1)
+ physical_sector_size = sector_size;
- if (!err && flush) {
- info->feature_flush = REQ_FLUSH;
- info->flush_op = BLKIF_OP_FLUSH_DISKCACHE;
+ err = blkfront_gather_backend_features(info);
+ if (err) {
+ xenbus_dev_fatal(info->xbdev, err, "setup_indirect at %s",
+ info->xbdev->otherend);
+ return;
}
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "feature-discard", "%d", &discard,
- NULL);
-
- if (!err && discard)
- blkfront_setup_discard(info);
-
- err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
- "feature-persistent", "%u", &persistent,
- NULL);
- if (err)
- info->feature_persistent = 0;
- else
- info->feature_persistent = persistent;
-
- err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
+ err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size,
+ physical_sector_size);
if (err) {
xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
info->xbdev->otherend);
dev_dbg(&dev->dev, "blkfront:blkback_changed to state %d.\n", backend_state);
switch (backend_state) {
- case XenbusStateInitialising:
case XenbusStateInitWait:
+ if (dev->state != XenbusStateInitialising)
+ break;
+ if (talk_to_blkback(dev, info)) {
+ kfree(info);
+ dev_set_drvdata(&dev->dev, NULL);
+ break;
+ }
+ case XenbusStateInitialising:
case XenbusStateInitialised:
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);
+ if (info)
+ blkfront_closing(info);
break;
}
}
bdev = bdget_disk(disk, 0);
+ if (!bdev) {
+ WARN(1, "Block device %s yanked out from us!\n", disk->disk_name);
+ goto out_mutex;
+ }
if (bdev->bd_openers)
goto out;
out:
bdput(bdev);
+out_mutex:
mutex_unlock(&blkfront_mutex);
}
{ "" }
};
-static DEFINE_XENBUS_DRIVER(blkfront, ,
+static struct xenbus_driver blkfront_driver = {
+ .ids = blkfront_ids,
.probe = blkfront_probe,
.remove = blkfront_remove,
.resume = blkfront_resume,
.otherend_changed = blkback_changed,
.is_ready = blkfront_is_ready,
-);
+};
static int __init xlblk_init(void)
{
if (!xen_domain())
return -ENODEV;
- if (xen_hvm_domain() && !xen_platform_pci_unplug)
+ if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) {
+ pr_info("Invalid max_ring_order (%d), will use default max: %d.\n",
+ xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER);
+ xen_blkif_max_ring_order = 0;
+ }
+
+ if (!xen_has_pv_disk_devices())
return -ENODEV;
if (register_blkdev(XENVBD_MAJOR, DEV_NAME)) {
projects / firefly-linux-kernel-4.4.55.git / blobdiff