xen_disk: remove use of grant map/unmap
Now that the (native or emulated) xen_be_copy_grant_refs() helper is always available, the xen_disk code can be significantly simplified by removing direct use of grant map and unmap operations. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> Acked-by: Anthony Perard <anthony.perard@citrix.com> Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
This commit is contained in:
Paul Durrant
Stefano Stabellini
parent
3fe12b8403
commit
06454c24ad
@ -36,27 +36,9 @@
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/* ------------------------------------------------------------- */
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static int batch_maps = 0;
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/* ------------------------------------------------------------- */
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#define BLOCK_SIZE 512
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#define IOCB_COUNT (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2)
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struct PersistentGrant {
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void *page;
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struct XenBlkDev *blkdev;
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};
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typedef struct PersistentGrant PersistentGrant;
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struct PersistentRegion {
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void *addr;
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int num;
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};
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typedef struct PersistentRegion PersistentRegion;
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struct ioreq {
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blkif_request_t req;
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int16_t status;
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@ -65,14 +47,11 @@ struct ioreq {
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off_t start;
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QEMUIOVector v;
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int presync;
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uint8_t mapped;
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/* grant mapping */
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uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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int prot;
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void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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void *pages;
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int num_unmap;
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/* aio status */
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int aio_inflight;
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@ -103,7 +82,6 @@ struct XenBlkDev {
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int protocol;
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blkif_back_rings_t rings;
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int more_work;
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int cnt_map;
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/* request lists */
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QLIST_HEAD(inflight_head, ioreq) inflight;
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@ -114,13 +92,7 @@ struct XenBlkDev {
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int requests_finished;
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unsigned int max_requests;
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/* Persistent grants extension */
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gboolean feature_discard;
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gboolean feature_persistent;
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GTree *persistent_gnts;
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GSList *persistent_regions;
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unsigned int persistent_gnt_count;
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unsigned int max_grants;
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/* qemu block driver */
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DriveInfo *dinfo;
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@ -139,10 +111,8 @@ static void ioreq_reset(struct ioreq *ioreq)
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ioreq->status = 0;
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ioreq->start = 0;
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ioreq->presync = 0;
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ioreq->mapped = 0;
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memset(ioreq->refs, 0, sizeof(ioreq->refs));
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ioreq->prot = 0;
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memset(ioreq->page, 0, sizeof(ioreq->page));
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ioreq->pages = NULL;
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@ -156,37 +126,6 @@ static void ioreq_reset(struct ioreq *ioreq)
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qemu_iovec_reset(&ioreq->v);
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}
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static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data)
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{
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uint ua = GPOINTER_TO_UINT(a);
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uint ub = GPOINTER_TO_UINT(b);
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return (ua > ub) - (ua < ub);
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}
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static void destroy_grant(gpointer pgnt)
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{
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PersistentGrant *grant = pgnt;
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struct XenBlkDev *blkdev = grant->blkdev;
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struct XenDevice *xendev = &blkdev->xendev;
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xen_be_unmap_grant_ref(xendev, grant->page);
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grant->blkdev->persistent_gnt_count--;
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xen_pv_printf(xendev, 3, "unmapped grant %p\n", grant->page);
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g_free(grant);
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}
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static void remove_persistent_region(gpointer data, gpointer dev)
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{
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PersistentRegion *region = data;
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struct XenBlkDev *blkdev = dev;
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struct XenDevice *xendev = &blkdev->xendev;
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xen_be_unmap_grant_refs(xendev, region->addr, region->num);
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xen_pv_printf(xendev, 3, "unmapped grant region %p with %d pages\n",
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region->addr, region->num);
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g_free(region);
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}
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static struct ioreq *ioreq_start(struct XenBlkDev *blkdev)
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{
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struct ioreq *ioreq = NULL;
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@ -254,7 +193,6 @@ static int ioreq_parse(struct ioreq *ioreq)
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ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number);
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switch (ioreq->req.operation) {
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case BLKIF_OP_READ:
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ioreq->prot = PROT_WRITE; /* to memory */
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break;
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case BLKIF_OP_FLUSH_DISKCACHE:
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ioreq->presync = 1;
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@ -263,7 +201,6 @@ static int ioreq_parse(struct ioreq *ioreq)
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}
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/* fall through */
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case BLKIF_OP_WRITE:
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ioreq->prot = PROT_READ; /* from memory */
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break;
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case BLKIF_OP_DISCARD:
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return 0;
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@ -310,171 +247,6 @@ err:
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return -1;
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}
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static void ioreq_unmap(struct ioreq *ioreq)
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{
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struct XenBlkDev *blkdev = ioreq->blkdev;
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struct XenDevice *xendev = &blkdev->xendev;
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int i;
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if (ioreq->num_unmap == 0 || ioreq->mapped == 0) {
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return;
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}
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if (batch_maps) {
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if (!ioreq->pages) {
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return;
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}
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xen_be_unmap_grant_refs(xendev, ioreq->pages, ioreq->num_unmap);
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ioreq->blkdev->cnt_map -= ioreq->num_unmap;
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ioreq->pages = NULL;
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} else {
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for (i = 0; i < ioreq->num_unmap; i++) {
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if (!ioreq->page[i]) {
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continue;
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}
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xen_be_unmap_grant_ref(xendev, ioreq->page[i]);
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ioreq->blkdev->cnt_map--;
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ioreq->page[i] = NULL;
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}
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}
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ioreq->mapped = 0;
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}
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static int ioreq_map(struct ioreq *ioreq)
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{
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struct XenBlkDev *blkdev = ioreq->blkdev;
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struct XenDevice *xendev = &blkdev->xendev;
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uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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int i, j, new_maps = 0;
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PersistentGrant *grant;
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PersistentRegion *region;
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/* refs variable will contain the information necessary
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* to map the grants that are needed to fulfill this request.
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*
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* After mapping the needed grants, the page array will contain the
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* memory address of each granted page in the order specified in ioreq
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* (disregarding if it's a persistent grant or not).
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*/
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if (ioreq->v.niov == 0 || ioreq->mapped == 1) {
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return 0;
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}
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if (ioreq->blkdev->feature_persistent) {
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for (i = 0; i < ioreq->v.niov; i++) {
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grant = g_tree_lookup(ioreq->blkdev->persistent_gnts,
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GUINT_TO_POINTER(ioreq->refs[i]));
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if (grant != NULL) {
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page[i] = grant->page;
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xen_pv_printf(&ioreq->blkdev->xendev, 3,
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"using persistent-grant %" PRIu32 "\n",
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ioreq->refs[i]);
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} else {
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/* Add the grant to the list of grants that
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* should be mapped
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*/
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refs[new_maps] = ioreq->refs[i];
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page[i] = NULL;
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new_maps++;
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}
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}
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/* Set the protection to RW, since grants may be reused later
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* with a different protection than the one needed for this request
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*/
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ioreq->prot = PROT_WRITE | PROT_READ;
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} else {
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/* All grants in the request should be mapped */
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memcpy(refs, ioreq->refs, sizeof(refs));
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memset(page, 0, sizeof(page));
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new_maps = ioreq->v.niov;
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}
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if (batch_maps && new_maps) {
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ioreq->pages = xen_be_map_grant_refs(xendev, refs, new_maps,
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ioreq->prot);
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if (ioreq->pages == NULL) {
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xen_pv_printf(&ioreq->blkdev->xendev, 0,
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"can't map %d grant refs (%s, %d maps)\n",
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new_maps, strerror(errno), ioreq->blkdev->cnt_map);
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return -1;
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}
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for (i = 0, j = 0; i < ioreq->v.niov; i++) {
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if (page[i] == NULL) {
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page[i] = ioreq->pages + (j++) * XC_PAGE_SIZE;
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}
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}
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ioreq->blkdev->cnt_map += new_maps;
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} else if (new_maps) {
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for (i = 0; i < new_maps; i++) {
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ioreq->page[i] = xen_be_map_grant_ref(xendev, refs[i],
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ioreq->prot);
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if (ioreq->page[i] == NULL) {
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xen_pv_printf(&ioreq->blkdev->xendev, 0,
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"can't map grant ref %d (%s, %d maps)\n",
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refs[i], strerror(errno), ioreq->blkdev->cnt_map);
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ioreq->mapped = 1;
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ioreq_unmap(ioreq);
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return -1;
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}
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ioreq->blkdev->cnt_map++;
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}
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for (i = 0, j = 0; i < ioreq->v.niov; i++) {
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if (page[i] == NULL) {
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page[i] = ioreq->page[j++];
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}
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}
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}
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if (ioreq->blkdev->feature_persistent && new_maps != 0 &&
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(!batch_maps || (ioreq->blkdev->persistent_gnt_count + new_maps <=
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ioreq->blkdev->max_grants))) {
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/*
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* If we are using persistent grants and batch mappings only
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* add the new maps to the list of persistent grants if the whole
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* area can be persistently mapped.
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*/
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if (batch_maps) {
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region = g_malloc0(sizeof(*region));
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region->addr = ioreq->pages;
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region->num = new_maps;
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ioreq->blkdev->persistent_regions = g_slist_append(
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ioreq->blkdev->persistent_regions,
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region);
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}
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while ((ioreq->blkdev->persistent_gnt_count < ioreq->blkdev->max_grants)
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&& new_maps) {
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/* Go through the list of newly mapped grants and add as many
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* as possible to the list of persistently mapped grants.
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*
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* Since we start at the end of ioreq->page(s), we only need
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* to decrease new_maps to prevent this granted pages from
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* being unmapped in ioreq_unmap.
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*/
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grant = g_malloc0(sizeof(*grant));
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new_maps--;
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if (batch_maps) {
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grant->page = ioreq->pages + (new_maps) * XC_PAGE_SIZE;
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} else {
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grant->page = ioreq->page[new_maps];
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}
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grant->blkdev = ioreq->blkdev;
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xen_pv_printf(&ioreq->blkdev->xendev, 3,
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"adding grant %" PRIu32 " page: %p\n",
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refs[new_maps], grant->page);
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g_tree_insert(ioreq->blkdev->persistent_gnts,
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GUINT_TO_POINTER(refs[new_maps]),
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grant);
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ioreq->blkdev->persistent_gnt_count++;
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}
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assert(!batch_maps || new_maps == 0);
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}
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for (i = 0; i < ioreq->v.niov; i++) {
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ioreq->v.iov[i].iov_base += (uintptr_t)page[i];
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}
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ioreq->mapped = 1;
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ioreq->num_unmap = new_maps;
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return 0;
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}
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static void ioreq_free_copy_buffers(struct ioreq *ioreq)
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{
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int i;
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@ -570,32 +342,28 @@ static void qemu_aio_complete(void *opaque, int ret)
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goto done;
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}
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if (xen_feature_grant_copy) {
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switch (ioreq->req.operation) {
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case BLKIF_OP_READ:
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/* in case of failure ioreq->aio_errors is increased */
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if (ret == 0) {
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ioreq_grant_copy(ioreq);
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}
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ioreq_free_copy_buffers(ioreq);
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break;
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case BLKIF_OP_WRITE:
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case BLKIF_OP_FLUSH_DISKCACHE:
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if (!ioreq->req.nr_segments) {
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break;
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}
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ioreq_free_copy_buffers(ioreq);
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break;
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default:
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switch (ioreq->req.operation) {
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case BLKIF_OP_READ:
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/* in case of failure ioreq->aio_errors is increased */
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if (ret == 0) {
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ioreq_grant_copy(ioreq);
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}
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ioreq_free_copy_buffers(ioreq);
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break;
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case BLKIF_OP_WRITE:
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case BLKIF_OP_FLUSH_DISKCACHE:
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if (!ioreq->req.nr_segments) {
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break;
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}
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ioreq_free_copy_buffers(ioreq);
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break;
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default:
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break;
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}
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ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
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if (!xen_feature_grant_copy) {
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ioreq_unmap(ioreq);
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}
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ioreq_finish(ioreq);
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switch (ioreq->req.operation) {
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case BLKIF_OP_WRITE:
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case BLKIF_OP_FLUSH_DISKCACHE:
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@ -655,18 +423,13 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
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{
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struct XenBlkDev *blkdev = ioreq->blkdev;
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if (xen_feature_grant_copy) {
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ioreq_init_copy_buffers(ioreq);
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if (ioreq->req.nr_segments && (ioreq->req.operation == BLKIF_OP_WRITE ||
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ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) &&
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ioreq_grant_copy(ioreq)) {
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ioreq_free_copy_buffers(ioreq);
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goto err;
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}
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} else {
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if (ioreq->req.nr_segments && ioreq_map(ioreq)) {
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goto err;
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}
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ioreq_init_copy_buffers(ioreq);
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if (ioreq->req.nr_segments &&
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(ioreq->req.operation == BLKIF_OP_WRITE ||
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ioreq->req.operation == BLKIF_OP_FLUSH_DISKCACHE) &&
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ioreq_grant_copy(ioreq)) {
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ioreq_free_copy_buffers(ioreq);
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goto err;
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}
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ioreq->aio_inflight++;
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@ -707,9 +470,6 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
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}
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default:
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/* unknown operation (shouldn't happen -- parse catches this) */
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if (!xen_feature_grant_copy) {
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ioreq_unmap(ioreq);
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}
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goto err;
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}
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@ -895,10 +655,6 @@ static void blk_alloc(struct XenDevice *xendev)
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blkdev->ctx = iothread_get_aio_context(blkdev->iothread);
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blkdev->bh = aio_bh_new(blkdev->ctx, blk_bh, blkdev);
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if (xen_mode != XEN_EMULATE) {
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batch_maps = 1;
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}
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}
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static void blk_parse_discard(struct XenBlkDev *blkdev)
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@ -981,15 +737,10 @@ static int blk_init(struct XenDevice *xendev)
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blkdev->file_blk = BLOCK_SIZE;
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xen_pv_printf(&blkdev->xendev, 3, "grant copy operation %s\n",
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xen_feature_grant_copy ? "enabled" : "disabled");
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/* fill info
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* blk_connect supplies sector-size and sectors
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*/
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xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1);
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xenstore_write_be_int(&blkdev->xendev, "feature-persistent",
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!xen_feature_grant_copy);
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xenstore_write_be_int(&blkdev->xendev, "info", info);
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xenstore_write_be_int(&blkdev->xendev, "max-ring-page-order",
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@ -1016,19 +767,10 @@ out_error:
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return -1;
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}
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/*
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* We need to account for the grant allocations requiring contiguous
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* chunks; the worst case number would be
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* max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1,
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* but in order to keep things simple just use
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* 2 * max_req * max_seg.
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*/
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#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg))
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static int blk_connect(struct XenDevice *xendev)
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{
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struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
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int pers, index, qflags;
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int index, qflags;
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bool readonly = true;
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bool writethrough = true;
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int order, ring_ref;
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@ -1150,11 +892,6 @@ static int blk_connect(struct XenDevice *xendev)
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&blkdev->xendev.remote_port) == -1) {
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return -1;
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}
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||||
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;
|
||||
@ -1189,11 +926,8 @@ static int blk_connect(struct XenDevice *xendev)
|
||||
return -1;
|
||||
}
|
||||
|
||||
/* Calculate the maximum number of grants needed by ioreqs */
|
||||
max_grants = MAX_GRANTS(blkdev->max_requests,
|
||||
BLKIF_MAX_SEGMENTS_PER_REQUEST);
|
||||
/* Add on the number needed for the ring pages */
|
||||
max_grants += blkdev->nr_ring_ref;
|
||||
max_grants = blkdev->nr_ring_ref;
|
||||
|
||||
xen_be_set_max_grant_refs(xendev, max_grants);
|
||||
|
||||
@ -1204,8 +938,6 @@ static int blk_connect(struct XenDevice *xendev)
|
||||
return -1;
|
||||
}
|
||||
|
||||
blkdev->cnt_map++;
|
||||
|
||||
switch (blkdev->protocol) {
|
||||
case BLKIF_PROTOCOL_NATIVE:
|
||||
{
|
||||
@ -1229,19 +961,6 @@ 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);
|
||||
@ -1274,29 +993,8 @@ static void blk_disconnect(struct XenDevice *xendev)
|
||||
if (blkdev->sring) {
|
||||
xen_be_unmap_grant_refs(xendev, blkdev->sring,
|
||||
blkdev->nr_ring_ref);
|
||||
blkdev->cnt_map--;
|
||||
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;
|
||||
}
|
||||
}
|
||||
|
||||
static int blk_free(struct XenDevice *xendev)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user