#include <linux/list.h>
#include <linux/delay.h>
#include <linux/freezer.h>
+#include <linux/bitmap.h>
#include <xen/events.h>
#include <xen/page.h>
#include <xen/xen.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
+#include <xen/balloon.h>
#include "common.h"
/*
unsigned short operation;
int status;
struct list_head free_list;
+ DECLARE_BITMAP(unmap_seg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
};
#define BLKBACK_INVALID_HANDLE (~0)
static struct xen_blkbk *blkbk;
+/*
+ * Maximum number of grant pages that can be mapped in blkback.
+ * BLKIF_MAX_SEGMENTS_PER_REQUEST * RING_SIZE is the maximum number of
+ * pages that blkback will persistently map.
+ * Currently, this is:
+ * RING_SIZE = 32 (for all known ring types)
+ * BLKIF_MAX_SEGMENTS_PER_REQUEST = 11
+ * sizeof(struct persistent_gnt) = 48
+ * So the maximum memory used to store the grants is:
+ * 32 * 11 * 48 = 16896 bytes
+ */
+static inline unsigned int max_mapped_grant_pages(enum blkif_protocol protocol)
+{
+ switch (protocol) {
+ case BLKIF_PROTOCOL_NATIVE:
+ return __CONST_RING_SIZE(blkif, PAGE_SIZE) *
+ BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ case BLKIF_PROTOCOL_X86_32:
+ return __CONST_RING_SIZE(blkif_x86_32, PAGE_SIZE) *
+ BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ case BLKIF_PROTOCOL_X86_64:
+ return __CONST_RING_SIZE(blkif_x86_64, PAGE_SIZE) *
+ BLKIF_MAX_SEGMENTS_PER_REQUEST;
+ default:
+ BUG();
+ }
+ return 0;
+}
+
+
/*
* Little helpful macro to figure out the index and virtual address of the
* pending_pages[..]. For each 'pending_req' we have have up to
static void make_response(struct xen_blkif *blkif, u64 id,
unsigned short op, int st);
+#define foreach_grant_safe(pos, n, rbtree, node) \
+ for ((pos) = container_of(rb_first((rbtree)), typeof(*(pos)), node), \
+ (n) = rb_next(&(pos)->node); \
+ &(pos)->node != NULL; \
+ (pos) = container_of(n, typeof(*(pos)), node), \
+ (n) = (&(pos)->node != NULL) ? rb_next(&(pos)->node) : NULL)
+
+
+static void add_persistent_gnt(struct rb_root *root,
+ struct persistent_gnt *persistent_gnt)
+{
+ struct rb_node **new = &(root->rb_node), *parent = NULL;
+ struct persistent_gnt *this;
+
+ /* Figure out where to put new node */
+ while (*new) {
+ this = container_of(*new, struct persistent_gnt, node);
+
+ parent = *new;
+ if (persistent_gnt->gnt < this->gnt)
+ new = &((*new)->rb_left);
+ else if (persistent_gnt->gnt > this->gnt)
+ new = &((*new)->rb_right);
+ else {
+ pr_alert(DRV_PFX " trying to add a gref that's already in the tree\n");
+ BUG();
+ }
+ }
+
+ /* Add new node and rebalance tree. */
+ rb_link_node(&(persistent_gnt->node), parent, new);
+ rb_insert_color(&(persistent_gnt->node), root);
+}
+
+static struct persistent_gnt *get_persistent_gnt(struct rb_root *root,
+ grant_ref_t gref)
+{
+ struct persistent_gnt *data;
+ struct rb_node *node = root->rb_node;
+
+ while (node) {
+ data = container_of(node, struct persistent_gnt, node);
+
+ if (gref < data->gnt)
+ node = node->rb_left;
+ else if (gref > data->gnt)
+ node = node->rb_right;
+ else
+ return data;
+ }
+ return NULL;
+}
+
+static void free_persistent_gnts(struct rb_root *root, unsigned int num)
+{
+ struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct persistent_gnt *persistent_gnt;
+ struct rb_node *n;
+ int ret = 0;
+ int segs_to_unmap = 0;
+
+ foreach_grant_safe(persistent_gnt, n, root, node) {
+ BUG_ON(persistent_gnt->handle ==
+ BLKBACK_INVALID_HANDLE);
+ gnttab_set_unmap_op(&unmap[segs_to_unmap],
+ (unsigned long) pfn_to_kaddr(page_to_pfn(
+ persistent_gnt->page)),
+ GNTMAP_host_map,
+ persistent_gnt->handle);
+
+ pages[segs_to_unmap] = persistent_gnt->page;
+
+ if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST ||
+ !rb_next(&persistent_gnt->node)) {
+ ret = gnttab_unmap_refs(unmap, NULL, pages,
+ segs_to_unmap);
+ BUG_ON(ret);
+ free_xenballooned_pages(segs_to_unmap, pages);
+ segs_to_unmap = 0;
+ }
+
+ rb_erase(&persistent_gnt->node, root);
+ kfree(persistent_gnt);
+ num--;
+ }
+ BUG_ON(num != 0);
+}
+
/*
* Retrieve from the 'pending_reqs' a free pending_req structure to be used.
*/
print_stats(blkif);
}
+ /* Free all persistent grant pages */
+ if (!RB_EMPTY_ROOT(&blkif->persistent_gnts))
+ free_persistent_gnts(&blkif->persistent_gnts,
+ blkif->persistent_gnt_c);
+
+ BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts));
+ blkif->persistent_gnt_c = 0;
+
if (log_stats)
print_stats(blkif);
int ret;
for (i = 0; i < req->nr_pages; i++) {
+ if (!test_bit(i, req->unmap_seg))
+ continue;
handle = pending_handle(req, i);
if (handle == BLKBACK_INVALID_HANDLE)
continue;
static int xen_blkbk_map(struct blkif_request *req,
struct pending_req *pending_req,
- struct seg_buf seg[])
+ struct seg_buf seg[],
+ struct page *pages[])
{
struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST];
- int i;
+ struct persistent_gnt *persistent_gnts[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct page *pages_to_gnt[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct persistent_gnt *persistent_gnt = NULL;
+ struct xen_blkif *blkif = pending_req->blkif;
+ phys_addr_t addr = 0;
+ int i, j;
+ bool new_map;
int nseg = req->u.rw.nr_segments;
+ int segs_to_map = 0;
int ret = 0;
+ int use_persistent_gnts;
+
+ use_persistent_gnts = (blkif->vbd.feature_gnt_persistent);
+
+ BUG_ON(blkif->persistent_gnt_c >
+ max_mapped_grant_pages(pending_req->blkif->blk_protocol));
/*
* Fill out preq.nr_sects with proper amount of sectors, and setup
for (i = 0; i < nseg; i++) {
uint32_t flags;
- flags = GNTMAP_host_map;
- if (pending_req->operation != BLKIF_OP_READ)
- flags |= GNTMAP_readonly;
- gnttab_set_map_op(&map[i], vaddr(pending_req, i), flags,
- req->u.rw.seg[i].gref,
- pending_req->blkif->domid);
+ if (use_persistent_gnts)
+ persistent_gnt = get_persistent_gnt(
+ &blkif->persistent_gnts,
+ req->u.rw.seg[i].gref);
+
+ if (persistent_gnt) {
+ /*
+ * We are using persistent grants and
+ * the grant is already mapped
+ */
+ new_map = false;
+ } else if (use_persistent_gnts &&
+ blkif->persistent_gnt_c <
+ max_mapped_grant_pages(blkif->blk_protocol)) {
+ /*
+ * We are using persistent grants, the grant is
+ * not mapped but we have room for it
+ */
+ new_map = true;
+ persistent_gnt = kmalloc(
+ sizeof(struct persistent_gnt),
+ GFP_KERNEL);
+ if (!persistent_gnt)
+ return -ENOMEM;
+ if (alloc_xenballooned_pages(1, &persistent_gnt->page,
+ false)) {
+ kfree(persistent_gnt);
+ return -ENOMEM;
+ }
+ persistent_gnt->gnt = req->u.rw.seg[i].gref;
+ persistent_gnt->handle = BLKBACK_INVALID_HANDLE;
+
+ pages_to_gnt[segs_to_map] =
+ persistent_gnt->page;
+ addr = (unsigned long) pfn_to_kaddr(
+ page_to_pfn(persistent_gnt->page));
+
+ add_persistent_gnt(&blkif->persistent_gnts,
+ persistent_gnt);
+ blkif->persistent_gnt_c++;
+ pr_debug(DRV_PFX " grant %u added to the tree of persistent grants, using %u/%u\n",
+ persistent_gnt->gnt, blkif->persistent_gnt_c,
+ max_mapped_grant_pages(blkif->blk_protocol));
+ } else {
+ /*
+ * We are either using persistent grants and
+ * hit the maximum limit of grants mapped,
+ * or we are not using persistent grants.
+ */
+ if (use_persistent_gnts &&
+ !blkif->vbd.overflow_max_grants) {
+ blkif->vbd.overflow_max_grants = 1;
+ pr_alert(DRV_PFX " domain %u, device %#x is using maximum number of persistent grants\n",
+ blkif->domid, blkif->vbd.handle);
+ }
+ new_map = true;
+ pages[i] = blkbk->pending_page(pending_req, i);
+ addr = vaddr(pending_req, i);
+ pages_to_gnt[segs_to_map] =
+ blkbk->pending_page(pending_req, i);
+ }
+
+ if (persistent_gnt) {
+ pages[i] = persistent_gnt->page;
+ persistent_gnts[i] = persistent_gnt;
+ } else {
+ persistent_gnts[i] = NULL;
+ }
+
+ if (new_map) {
+ flags = GNTMAP_host_map;
+ if (!persistent_gnt &&
+ (pending_req->operation != BLKIF_OP_READ))
+ flags |= GNTMAP_readonly;
+ gnttab_set_map_op(&map[segs_to_map++], addr,
+ flags, req->u.rw.seg[i].gref,
+ blkif->domid);
+ }
}
- ret = gnttab_map_refs(map, NULL, &blkbk->pending_page(pending_req, 0), nseg);
- BUG_ON(ret);
+ if (segs_to_map) {
+ ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map);
+ BUG_ON(ret);
+ }
/*
* Now swizzle the MFN in our domain with the MFN from the other domain
* so that when we access vaddr(pending_req,i) it has the contents of
* the page from the other domain.
*/
- for (i = 0; i < nseg; i++) {
- if (unlikely(map[i].status != 0)) {
- pr_debug(DRV_PFX "invalid buffer -- could not remap it\n");
- map[i].handle = BLKBACK_INVALID_HANDLE;
- ret |= 1;
+ bitmap_zero(pending_req->unmap_seg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ for (i = 0, j = 0; i < nseg; i++) {
+ if (!persistent_gnts[i] ||
+ persistent_gnts[i]->handle == BLKBACK_INVALID_HANDLE) {
+ /* This is a newly mapped grant */
+ BUG_ON(j >= segs_to_map);
+ if (unlikely(map[j].status != 0)) {
+ pr_debug(DRV_PFX "invalid buffer -- could not remap it\n");
+ map[j].handle = BLKBACK_INVALID_HANDLE;
+ ret |= 1;
+ if (persistent_gnts[i]) {
+ rb_erase(&persistent_gnts[i]->node,
+ &blkif->persistent_gnts);
+ blkif->persistent_gnt_c--;
+ kfree(persistent_gnts[i]);
+ persistent_gnts[i] = NULL;
+ }
+ }
+ }
+ if (persistent_gnts[i]) {
+ if (persistent_gnts[i]->handle ==
+ BLKBACK_INVALID_HANDLE) {
+ /*
+ * If this is a new persistent grant
+ * save the handler
+ */
+ persistent_gnts[i]->handle = map[j].handle;
+ persistent_gnts[i]->dev_bus_addr =
+ map[j++].dev_bus_addr;
+ }
+ pending_handle(pending_req, i) =
+ persistent_gnts[i]->handle;
+
+ if (ret)
+ continue;
+
+ seg[i].buf = persistent_gnts[i]->dev_bus_addr |
+ (req->u.rw.seg[i].first_sect << 9);
+ } else {
+ pending_handle(pending_req, i) = map[j].handle;
+ bitmap_set(pending_req->unmap_seg, i, 1);
+
+ if (ret) {
+ j++;
+ continue;
+ }
+
+ seg[i].buf = map[j++].dev_bus_addr |
+ (req->u.rw.seg[i].first_sect << 9);
}
-
- pending_handle(pending_req, i) = map[i].handle;
-
- if (ret)
- continue;
-
- seg[i].buf = map[i].dev_bus_addr |
- (req->u.rw.seg[i].first_sect << 9);
}
return ret;
}
return err;
}
+static int dispatch_other_io(struct xen_blkif *blkif,
+ struct blkif_request *req,
+ struct pending_req *pending_req)
+{
+ free_req(pending_req);
+ make_response(blkif, req->u.other.id, req->operation,
+ BLKIF_RSP_EOPNOTSUPP);
+ return -EIO;
+}
+
static void xen_blk_drain_io(struct xen_blkif *blkif)
{
atomic_set(&blkif->drain, 1);
/* Apply all sanity checks to /private copy/ of request. */
barrier();
- if (unlikely(req.operation == BLKIF_OP_DISCARD)) {
+
+ switch (req.operation) {
+ case BLKIF_OP_READ:
+ case BLKIF_OP_WRITE:
+ case BLKIF_OP_WRITE_BARRIER:
+ case BLKIF_OP_FLUSH_DISKCACHE:
+ if (dispatch_rw_block_io(blkif, &req, pending_req))
+ goto done;
+ break;
+ case BLKIF_OP_DISCARD:
free_req(pending_req);
if (dispatch_discard_io(blkif, &req))
- break;
- } else if (dispatch_rw_block_io(blkif, &req, pending_req))
+ goto done;
+ break;
+ default:
+ if (dispatch_other_io(blkif, &req, pending_req))
+ goto done;
break;
+ }
/* Yield point for this unbounded loop. */
cond_resched();
}
-
+done:
return more_to_do;
}
int operation;
struct blk_plug plug;
bool drain = false;
+ struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
switch (req->operation) {
case BLKIF_OP_READ:
goto fail_response;
}
- preq.dev = req->u.rw.handle;
preq.sector_number = req->u.rw.sector_number;
preq.nr_sects = 0;
pr_debug(DRV_PFX "access denied: %s of [%llu,%llu] on dev=%04x\n",
operation == READ ? "read" : "write",
preq.sector_number,
- preq.sector_number + preq.nr_sects, preq.dev);
+ preq.sector_number + preq.nr_sects,
+ blkif->vbd.pdevice);
goto fail_response;
}
* the hypercall to unmap the grants - that is all done in
* xen_blkbk_unmap.
*/
- if (xen_blkbk_map(req, pending_req, seg))
+ if (xen_blkbk_map(req, pending_req, seg, pages))
goto fail_flush;
/*
for (i = 0; i < nseg; i++) {
while ((bio == NULL) ||
(bio_add_page(bio,
- blkbk->pending_page(pending_req, i),
+ pages[i],
seg[i].nsec << 9,
seg[i].buf & ~PAGE_MASK) == 0)) {
projects / cascardo / linux.git / blobdiff