1 files changed, 91 insertions, 63 deletions

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index c3dae2e0f290..a894f88762d8 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -44,7 +44,7 @@
 #include <linux/mutex.h>
 #include <linux/scatterlist.h>
 #include <linux/bitmap.h>
-#include <linux/llist.h>
+#include <linux/list.h>
 
 #include <xen/xen.h>
 #include <xen/xenbus.h>
@@ -68,13 +68,12 @@ enum blkif_state {
 struct grant {
         grant_ref_t gref;
         unsigned long pfn;
-        struct llist_node node;
+        struct list_head node;
 };
 
 struct blk_shadow {
         struct blkif_request req;
         struct request *request;
-        unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
         struct grant *grants_used[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 };
 
@@ -105,7 +104,7 @@ struct blkfront_info
         struct work_struct work;
         struct gnttab_free_callback callback;
         struct blk_shadow shadow[BLK_RING_SIZE];
-        struct llist_head persistent_gnts;
+        struct list_head persistent_gnts;
         unsigned int persistent_gnts_c;
         unsigned long shadow_free;
         unsigned int feature_flush;
@@ -165,6 +164,69 @@ static int add_id_to_freelist(struct blkfront_info *info,
         return 0;
 }
 
+static int fill_grant_buffer(struct blkfront_info *info, int num)
+{
+        struct page *granted_page;
+        struct grant *gnt_list_entry, *n;
+        int i = 0;
+
+        while(i < num) {
+                gnt_list_entry = kzalloc(sizeof(struct grant), GFP_NOIO);
+                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;
+                }
+
+                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);
+                i++;
+        }
+
+        return 0;
+
+out_of_memory:
+        list_for_each_entry_safe(gnt_list_entry, n,
+                                 &info->persistent_gnts, node) {
+                list_del(&gnt_list_entry->node);
+                __free_page(pfn_to_page(gnt_list_entry->pfn));
+                kfree(gnt_list_entry);
+                i--;
+        }
+        BUG_ON(i != 0);
+        return -ENOMEM;
+}
+
+static struct grant *get_grant(grant_ref_t *gref_head,
+                               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);
+        list_del(&gnt_list_entry->node);
+
+        if (gnt_list_entry->gref != GRANT_INVALID_REF) {
+                info->persistent_gnts_c--;
+                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);
+        return gnt_list_entry;
+}
+
 static const char *op_name(int op)
 {
         static const char *const names[] = {
@@ -293,7 +355,6 @@ static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
 static int blkif_queue_request(struct request *req)
 {
         struct blkfront_info *info = req->rq_disk->private_data;
-        unsigned long buffer_mfn;
         struct blkif_request *ring_req;
         unsigned long id;
         unsigned int fsect, lsect;
@@ -306,7 +367,6 @@ static int blkif_queue_request(struct request *req)
          */
         bool new_persistent_gnts;
         grant_ref_t gref_head;
-        struct page *granted_page;
         struct grant *gnt_list_entry = NULL;
         struct scatterlist *sg;
 
@@ -370,41 +430,8 @@ static int blkif_queue_request(struct request *req)
                         fsect = sg->offset >> 9;
                         lsect = fsect + (sg->length >> 9) - 1;
 
-                        if (info->persistent_gnts_c) {
-                                BUG_ON(llist_empty(&info->persistent_gnts));
-                                gnt_list_entry = llist_entry(
-                                        llist_del_first(&info->persistent_gnts),
-                                        struct grant, node);
-
-                                ref = gnt_list_entry->gref;
-                                buffer_mfn = pfn_to_mfn(gnt_list_entry->pfn);
-                                info->persistent_gnts_c--;
-                        } else {
-                                ref = gnttab_claim_grant_reference(&gref_head);
-                                BUG_ON(ref == -ENOSPC);
-
-                                gnt_list_entry =
-                                        kmalloc(sizeof(struct grant),
-                                                         GFP_ATOMIC);
-                                if (!gnt_list_entry)
-                                        return -ENOMEM;
-
-                                granted_page = alloc_page(GFP_ATOMIC);
-                                if (!granted_page) {
-                                        kfree(gnt_list_entry);
-                                        return -ENOMEM;
-                                }
-
-                                gnt_list_entry->pfn =
-                                        page_to_pfn(granted_page);
-                                gnt_list_entry->gref = ref;
-
-                                buffer_mfn = pfn_to_mfn(page_to_pfn(
-                                                                granted_page));
-                                gnttab_grant_foreign_access_ref(ref,
-                                        info->xbdev->otherend_id,
-                                        buffer_mfn, 0);
-                        }
+                        gnt_list_entry = get_grant(&gref_head, info);
+                        ref = gnt_list_entry->gref;
 
                         info->shadow[id].grants_used[i] = gnt_list_entry;
 
@@ -435,7 +462,6 @@ static int blkif_queue_request(struct request *req)
                                 kunmap_atomic(shared_data);
                         }
 
-                        info->shadow[id].frame[i] = mfn_to_pfn(buffer_mfn);
                         ring_req->u.rw.seg[i] =
                                         (struct blkif_request_segment) {
                                                 .gref       = ref,
@@ -790,9 +816,8 @@ static void blkif_restart_queue(struct work_struct *work)
 
 static void blkif_free(struct blkfront_info *info, int suspend)
 {
-        struct llist_node *all_gnts;
-        struct grant *persistent_gnt, *tmp;
-        struct llist_node *n;
+        struct grant *persistent_gnt;
+        struct grant *n;
 
         /* Prevent new requests being issued until we fix things up. */
         spin_lock_irq(&info->io_lock);
@@ -803,22 +828,20 @@ static void blkif_free(struct blkfront_info *info, int suspend)
                 blk_stop_queue(info->rq);
 
         /* Remove all persistent grants */
-        if (info->persistent_gnts_c) {
-                all_gnts = llist_del_all(&info->persistent_gnts);
-                persistent_gnt = llist_entry(all_gnts, typeof(*(persistent_gnt)), node);
-                while (persistent_gnt) {
-                        gnttab_end_foreign_access(persistent_gnt->gref, 0, 0UL);
+        if (!list_empty(&info->persistent_gnts)) {
+                list_for_each_entry_safe(persistent_gnt, n,
+                                         &info->persistent_gnts, 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));
-                        tmp = persistent_gnt;
-                        n = persistent_gnt->node.next;
-                        if (n)
-                                persistent_gnt = llist_entry(n, typeof(*(persistent_gnt)), node);
-                        else
-                                persistent_gnt = NULL;
-                        kfree(tmp);
+                        kfree(persistent_gnt);
                 }
-                info->persistent_gnts_c = 0;
         }
+        BUG_ON(info->persistent_gnts_c != 0);
 
         /* No more gnttab callback work. */
         gnttab_cancel_free_callback(&info->callback);
@@ -875,7 +898,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
         }
         /* Add the persistent grant into the list of free grants */
         for (i = 0; i < s->req.u.rw.nr_segments; i++) {
-                llist_add(&s->grants_used[i]->node, &info->persistent_gnts);
+                list_add(&s->grants_used[i]->node, &info->persistent_gnts);
                 info->persistent_gnts_c++;
         }
 }
@@ -1013,6 +1036,12 @@ static int setup_blkring(struct xenbus_device *dev,
 
         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));
         if (err < 0) {
                 free_page((unsigned long)sring);
@@ -1171,7 +1200,7 @@ static int blkfront_probe(struct xenbus_device *dev,
         spin_lock_init(&info->io_lock);
         info->xbdev = dev;
         info->vdevice = vdevice;
-        init_llist_head(&info->persistent_gnts);
+        INIT_LIST_HEAD(&info->persistent_gnts);
         info->persistent_gnts_c = 0;
         info->connected = BLKIF_STATE_DISCONNECTED;
         INIT_WORK(&info->work, blkif_restart_queue);
@@ -1203,11 +1232,10 @@ static int blkif_recover(struct blkfront_info *info)
         int j;
 
         /* Stage 1: Make a safe copy of the shadow state. */
-        copy = kmalloc(sizeof(info->shadow),
+        copy = kmemdup(info->shadow, sizeof(info->shadow),
                        GFP_NOIO | __GFP_REPEAT | __GFP_HIGH);
         if (!copy)
                 return -ENOMEM;
-        memcpy(copy, info->shadow, sizeof(info->shadow));
 
         /* Stage 2: Set up free list. */
         memset(&info->shadow, 0, sizeof(info->shadow));
@@ -1236,7 +1264,7 @@ static int blkif_recover(struct blkfront_info *info)
                                 gnttab_grant_foreign_access_ref(
                                         req->u.rw.seg[j].gref,
                                         info->xbdev->otherend_id,
-                                        pfn_to_mfn(info->shadow[req->u.rw.id].frame[j]),
+                                        pfn_to_mfn(copy[i].grants_used[j]->pfn),
                                         0);
                 }
                 info->shadow[req->u.rw.id].req = *req;