The grant copy operation was added to libxengnttab in Xen 4.8.0. If grant
copy is available then persistent grants will not be used.
The xen_disk source can be siginificantly simplified by removing this now
redundant code.
Signed-off-by: Paul Durrant <paul.durr...@citrix.com>
---
Cc: Stefano Stabellini <sstabell...@kernel.org>
Cc: Anthony Perard <anthony.per...@citrix.com>
Cc: Kevin Wolf <kw...@redhat.com>
Cc: Max Reitz <mre...@redhat.com>
---
hw/block/xen_disk.c | 237 +++++-----------------------------------------------
1 file changed, 21 insertions(+), 216 deletions(-)
diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
index f74fcd4..b33611a 100644
--- a/hw/block/xen_disk.c
+++ b/hw/block/xen_disk.c
@@ -43,20 +43,6 @@ static int batch_maps = 0;
#define BLOCK_SIZE 512
#define IOCB_COUNT (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2)
-struct PersistentGrant {
- void *page;
- struct XenBlkDev *blkdev;
-};
-
-typedef struct PersistentGrant PersistentGrant;
-
-struct PersistentRegion {
- void *addr;
- int num;
-};
-
-typedef struct PersistentRegion PersistentRegion;
-
struct ioreq {
blkif_request_t req;
int16_t status;
@@ -73,7 +59,6 @@ struct ioreq {
int prot;
void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
void *pages;
- int num_unmap;
/* aio status */
int aio_inflight;
@@ -115,13 +100,7 @@ struct XenBlkDev {
int requests_finished;
unsigned int max_requests;
- /* Persistent grants extension */
gboolean feature_discard;
- gboolean feature_persistent;
- GTree *persistent_gnts;
- GSList *persistent_regions;
- unsigned int persistent_gnt_count;
- unsigned int max_grants;
/* qemu block driver */
DriveInfo *dinfo;
@@ -158,46 +137,6 @@ static void ioreq_reset(struct ioreq *ioreq)
qemu_iovec_reset(&ioreq->v);
}
-static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
-{
- uint ua = GPOINTER_TO_UINT(a);
- uint ub = GPOINTER_TO_UINT(b);
- return (ua > ub) - (ua < ub);
-}
-
-static void destroy_grant(gpointer pgnt)
-{
- PersistentGrant *grant = pgnt;
- xengnttab_handle *gnt = grant->blkdev->xendev.gnttabdev;
-
- if (xengnttab_unmap(gnt, grant->page, 1) != 0) {
- xen_pv_printf(&grant->blkdev->xendev, 0,
- "xengnttab_unmap failed: %s\n",
- strerror(errno));
- }
- grant->blkdev->persistent_gnt_count--;
- xen_pv_printf(&grant->blkdev->xendev, 3,
- "unmapped grant %p\n", grant->page);
- g_free(grant);
-}
-
-static void remove_persistent_region(gpointer data, gpointer dev)
-{
- PersistentRegion *region = data;
- struct XenBlkDev *blkdev = dev;
- xengnttab_handle *gnt = blkdev->xendev.gnttabdev;
-
- if (xengnttab_unmap(gnt, region->addr, region->num) != 0) {
- xen_pv_printf(&blkdev->xendev, 0,
- "xengnttab_unmap region %p failed: %s\n",
- region->addr, strerror(errno));
- }
- xen_pv_printf(&blkdev->xendev, 3,
- "unmapped grant region %p with %d pages\n",
- region->addr, region->num);
- g_free(region);
-}
-
static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
{
struct ioreq *ioreq = NULL;
@@ -327,22 +266,22 @@ static void ioreq_unmap(struct ioreq *ioreq)
xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
int i;
- if (ioreq->num_unmap == 0 || ioreq->mapped == 0) {
+ if (ioreq->v.niov == 0 || ioreq->mapped == 0) {
return;
}
if (batch_maps) {
if (!ioreq->pages) {
return;
}
- if (xengnttab_unmap(gnt, ioreq->pages, ioreq->num_unmap) != 0) {
+ if (xengnttab_unmap(gnt, ioreq->pages, ioreq->v.niov) != 0) {
xen_pv_printf(&ioreq->blkdev->xendev, 0,
"xengnttab_unmap failed: %s\n",
strerror(errno));
}
- ioreq->blkdev->cnt_map -= ioreq->num_unmap;
+ ioreq->blkdev->cnt_map -= ioreq->v.niov;
ioreq->pages = NULL;
} else {
- for (i = 0; i < ioreq->num_unmap; i++) {
+ for (i = 0; i < ioreq->v.niov; i++) {
if (!ioreq->page[i]) {
continue;
}
@@ -361,138 +300,44 @@ static void ioreq_unmap(struct ioreq *ioreq)
static int ioreq_map(struct ioreq *ioreq)
{
xengnttab_handle *gnt = ioreq->blkdev->xendev.gnttabdev;
- uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST];
- uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
- void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
- int i, j, new_maps = 0;
- PersistentGrant *grant;
- PersistentRegion *region;
- /* domids and refs variables will contain the information necessary
- * to map the grants that are needed to fulfill this request.
- *
- * After mapping the needed grants, the page array will contain the
- * memory address of each granted page in the order specified in ioreq
- * (disregarding if it's a persistent grant or not).
- */
+ int i;
if (ioreq->v.niov == 0 || ioreq->mapped == 1) {
return 0;
}
- if (ioreq->blkdev->feature_persistent) {
- for (i = 0; i < ioreq->v.niov; i++) {
- grant = g_tree_lookup(ioreq->blkdev->persistent_gnts,
- GUINT_TO_POINTER(ioreq->refs[i]));
-
- if (grant != NULL) {
- page[i] = grant->page;
- xen_pv_printf(&ioreq->blkdev->xendev, 3,
- "using persistent-grant %" PRIu32 "\n",
- ioreq->refs[i]);
- } else {
- /* Add the grant to the list of grants that
- * should be mapped
- */
- domids[new_maps] = ioreq->domids[i];
- refs[new_maps] = ioreq->refs[i];
- page[i] = NULL;
- new_maps++;
- }
- }
- /* Set the protection to RW, since grants may be reused later
- * with a different protection than the one needed for this request
- */
- ioreq->prot = PROT_WRITE | PROT_READ;
- } else {
- /* All grants in the request should be mapped */
- memcpy(refs, ioreq->refs, sizeof(refs));
- memcpy(domids, ioreq->domids, sizeof(domids));
- memset(page, 0, sizeof(page));
- new_maps = ioreq->v.niov;
- }
-
- if (batch_maps && new_maps) {
+ if (batch_maps) {
ioreq->pages = xengnttab_map_grant_refs
- (gnt, new_maps, domids, refs, ioreq->prot);
+ (gnt, ioreq->v.niov, ioreq->domids, ioreq->refs, ioreq->prot);
if (ioreq->pages == NULL) {
xen_pv_printf(&ioreq->blkdev->xendev, 0,
"can't map %d grant refs (%s, %d maps)\n",
- new_maps, strerror(errno), ioreq->blkdev->cnt_map);
+ ioreq->v.niov, strerror(errno),
+ ioreq->blkdev->cnt_map);
return -1;
}
- for (i = 0, j = 0; i < ioreq->v.niov; i++) {
- if (page[i] == NULL) {
- page[i] = ioreq->pages + (j++) * XC_PAGE_SIZE;
- }
+ for (i = 0; i < ioreq->v.niov; i++) {
+ ioreq->v.iov[i].iov_base = ioreq->pages + i * XC_PAGE_SIZE +
+ (uintptr_t)ioreq->v.iov[i].iov_base;
}
- ioreq->blkdev->cnt_map += new_maps;
- } else if (new_maps) {
- for (i = 0; i < new_maps; i++) {
+ ioreq->blkdev->cnt_map += ioreq->v.niov;
+ } else {
+ for (i = 0; i < ioreq->v.niov; i++) {
ioreq->page[i] = xengnttab_map_grant_ref
- (gnt, domids[i], refs[i], ioreq->prot);
+ (gnt, ioreq->domids[i], ioreq->refs[i], ioreq->prot);
if (ioreq->page[i] == NULL) {
xen_pv_printf(&ioreq->blkdev->xendev, 0,
"can't map grant ref %d (%s, %d maps)\n",
- refs[i], strerror(errno),
ioreq->blkdev->cnt_map);
+ ioreq->refs[i], strerror(errno),
+ ioreq->blkdev->cnt_map);
ioreq->mapped = 1;
ioreq_unmap(ioreq);
return -1;
}
- ioreq->blkdev->cnt_map++;
- }
- for (i = 0, j = 0; i < ioreq->v.niov; i++) {
- if (page[i] == NULL) {
- page[i] = ioreq->page[j++];
- }
+ ioreq->v.iov[i].iov_base = ioreq->page[i] +
+ (uintptr_t)ioreq->v.iov[i].iov_base;
}
}
- if (ioreq->blkdev->feature_persistent && new_maps != 0 &&
- (!batch_maps || (ioreq->blkdev->persistent_gnt_count + new_maps <=
- ioreq->blkdev->max_grants))) {
- /*
- * If we are using persistent grants and batch mappings only
- * add the new maps to the list of persistent grants if the whole
- * area can be persistently mapped.
- */
- if (batch_maps) {
- region = g_malloc0(sizeof(*region));
- region->addr = ioreq->pages;
- region->num = new_maps;
- ioreq->blkdev->persistent_regions = g_slist_append(
- ioreq->blkdev->persistent_regions,
- region);
- }
- while ((ioreq->blkdev->persistent_gnt_count <
ioreq->blkdev->max_grants)
- && new_maps) {
- /* Go through the list of newly mapped grants and add as many
- * as possible to the list of persistently mapped grants.
- *
- * Since we start at the end of ioreq->page(s), we only need
- * to decrease new_maps to prevent this granted pages from
- * being unmapped in ioreq_unmap.
- */
- grant = g_malloc0(sizeof(*grant));
- new_maps--;
- if (batch_maps) {
- grant->page = ioreq->pages + (new_maps) * XC_PAGE_SIZE;
- } else {
- grant->page = ioreq->page[new_maps];
- }
- grant->blkdev = ioreq->blkdev;
- xen_pv_printf(&ioreq->blkdev->xendev, 3,
- "adding grant %" PRIu32 " page: %p\n",
- refs[new_maps], grant->page);
- g_tree_insert(ioreq->blkdev->persistent_gnts,
- GUINT_TO_POINTER(refs[new_maps]),
- grant);
- ioreq->blkdev->persistent_gnt_count++;
- }
- assert(!batch_maps || new_maps == 0);
- }
- for (i = 0; i < ioreq->v.niov; i++) {
- ioreq->v.iov[i].iov_base += (uintptr_t)page[i];
- }
ioreq->mapped = 1;
- ioreq->num_unmap = new_maps;
return 0;
}
@@ -1039,8 +884,6 @@ static int blk_init(struct XenDevice *xendev)
* blk_connect supplies sector-size and sectors
*/
xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1);
- xenstore_write_be_int(&blkdev->xendev, "feature-persistent",
- !xen_feature_grant_copy);
xenstore_write_be_int(&blkdev->xendev, "info", info);
xenstore_write_be_int(&blkdev->xendev, "max-ring-page-order",
@@ -1079,7 +922,7 @@ out_error:
static int blk_connect(struct XenDevice *xendev)
{
struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
- int pers, index, qflags;
+ int index, qflags;
bool readonly = true;
bool writethrough = true;
int order, ring_ref;
@@ -1202,11 +1045,6 @@ static int blk_connect(struct XenDevice *xendev)
&blkdev->xendev.remote_port) == -1) {
return -1;
}
- if (xenstore_read_fe_int(&blkdev->xendev, "feature-persistent", &pers)) {
- blkdev->feature_persistent = FALSE;
- } else {
- blkdev->feature_persistent = !!pers;
- }
if (!blkdev->xendev.protocol) {
blkdev->protocol = BLKIF_PROTOCOL_NATIVE;
@@ -1301,19 +1139,6 @@ static int blk_connect(struct XenDevice *xendev)
}
}
- if (blkdev->feature_persistent) {
- /* Init persistent grants */
- blkdev->max_grants = blkdev->max_requests *
- BLKIF_MAX_SEGMENTS_PER_REQUEST;
- blkdev->persistent_gnts = g_tree_new_full((GCompareDataFunc)int_cmp,
- NULL, NULL,
- batch_maps ?
- (GDestroyNotify)g_free :
- (GDestroyNotify)destroy_grant);
- blkdev->persistent_regions = NULL;
- blkdev->persistent_gnt_count = 0;
- }
-
blk_set_aio_context(blkdev->blk, blkdev->ctx);
xen_be_bind_evtchn(&blkdev->xendev);
@@ -1350,26 +1175,6 @@ static void blk_disconnect(struct XenDevice *xendev)
blkdev->sring = NULL;
}
- /*
- * Unmap persistent grants before switching to the closed state
- * so the frontend can free them.
- *
- * In the !batch_maps case g_tree_destroy will take care of unmapping
- * the grant, but in the batch_maps case we need to iterate over every
- * region in persistent_regions and unmap it.
- */
- if (blkdev->feature_persistent) {
- g_tree_destroy(blkdev->persistent_gnts);
- assert(batch_maps || blkdev->persistent_gnt_count == 0);
- if (batch_maps) {
- blkdev->persistent_gnt_count = 0;
- g_slist_foreach(blkdev->persistent_regions,
- (GFunc)remove_persistent_region, blkdev);
- g_slist_free(blkdev->persistent_regions);
- }
- blkdev->feature_persistent = false;
- }
-
if (blkdev->xendev.gnttabdev) {
xengnttab_close(blkdev->xendev.gnttabdev);
blkdev->xendev.gnttabdev = NULL;
--
2.1.4
