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[Xen-devel] [PATCH 3/6] xen-gntdev: Remove unneeded structures from gran

To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] [PATCH 3/6] xen-gntdev: Remove unneeded structures from grant_map tracking data
From: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
Date: Tue, 14 Dec 2010 09:55:50 -0500
Cc: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>, Ian.Campbell@xxxxxxxxxx
Delivery-date: Tue, 14 Dec 2010 07:01:49 -0800
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The entire hypercall argument list isn't required; only selected
fields from the hypercall need to be tracked between the ioctl, map,
and unmap operations.

Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
 drivers/xen/gntdev.c |  195 +++++++++++++++++++++++++++++--------------------
 1 files changed, 115 insertions(+), 80 deletions(-)

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 62639af..773b76c 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -55,17 +55,23 @@ struct gntdev_priv {
        struct mmu_notifier mn;
 };
 
+struct granted_page {
+       u64 pte_maddr;
+       union {
+               struct ioctl_gntdev_grant_ref target;
+               grant_handle_t handle;
+       };
+};
+
 struct grant_map {
        struct list_head next;
        struct gntdev_priv *priv;
        struct vm_area_struct *vma;
        int index;
        int count;
-       int flags;
-       int is_mapped;
-       struct ioctl_gntdev_grant_ref *grants;
-       struct gnttab_map_grant_ref   *map_ops;
-       struct gnttab_unmap_grant_ref *unmap_ops;
+       int is_mapped:1;
+       int is_ro:1;
+       struct granted_page pages[0];
 };
 
 /* ------------------------------------------------------------------ */
@@ -83,40 +89,28 @@ static void gntdev_print_maps(struct gntdev_priv *priv,
                       map->index == text_index && text ? text : "");
 }
 
-static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
+static struct grant_map *gntdev_alloc_map(int count,
+               struct ioctl_gntdev_grant_ref* grants)
 {
        struct grant_map *add;
+       int i;
 
-       add = kzalloc(sizeof(struct grant_map), GFP_KERNEL);
-       if (NULL == add)
+       add = kzalloc(sizeof(*add) + sizeof(add->pages[0])*count, GFP_KERNEL);
+       if (!add)
                return NULL;
 
-       add->grants    = kzalloc(sizeof(add->grants[0])    * count, GFP_KERNEL);
-       add->map_ops   = kzalloc(sizeof(add->map_ops[0])   * count, GFP_KERNEL);
-       add->unmap_ops = kzalloc(sizeof(add->unmap_ops[0]) * count, GFP_KERNEL);
-       if (NULL == add->grants  ||
-           NULL == add->map_ops ||
-           NULL == add->unmap_ops)
-               goto err;
-
-       add->index = 0;
        add->count = count;
-       add->priv  = priv;
+       for(i = 0; i < count; i++)
+               add->pages[i].target = grants[i];
 
        return add;
-
-err:
-       kfree(add->grants);
-       kfree(add->map_ops);
-       kfree(add->unmap_ops);
-       kfree(add);
-       return NULL;
 }
 
 static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add)
 {
        struct grant_map *map;
 
+       spin_lock(&priv->lock);
        list_for_each_entry(map, &priv->maps, next) {
                if (add->index + add->count < map->index) {
                        list_add_tail(&add->next, &map->next);
@@ -127,8 +121,10 @@ static void gntdev_add_map(struct gntdev_priv *priv, 
struct grant_map *add)
        list_add_tail(&add->next, &priv->maps);
 
 done:
+       add->priv = priv;
        if (debug)
                gntdev_print_maps(priv, "[new]", add->index);
+       spin_unlock(&priv->lock);
 }
 
 static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv, int 
index,
@@ -169,9 +165,10 @@ static int gntdev_del_map(struct grant_map *map)
 
        if (map->vma)
                return -EBUSY;
-       for (i = 0; i < map->count; i++)
-               if (map->unmap_ops[i].handle)
-                       return -EBUSY;
+       if (map->is_mapped)
+               for (i = 0; i < map->count; i++)
+                       if (map->pages[i].handle)
+                               return -EBUSY;
 
        atomic_sub(map->count, &pages_mapped);
        list_del(&map->next);
@@ -182,9 +179,6 @@ static void gntdev_free_map(struct grant_map *map)
 {
        if (!map)
                return;
-       kfree(map->grants);
-       kfree(map->map_ops);
-       kfree(map->unmap_ops);
        kfree(map);
 }
 
@@ -199,51 +193,91 @@ static int find_grant_ptes(pte_t *pte, pgtable_t token, 
unsigned long addr, void
        BUG_ON(pgnr >= map->count);
        pte_maddr  = (u64)pfn_to_mfn(page_to_pfn(token)) << PAGE_SHIFT;
        pte_maddr += (unsigned long)pte & ~PAGE_MASK;
-       gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, map->flags,
-                         map->grants[pgnr].ref,
-                         map->grants[pgnr].domid);
-       gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, map->flags,
-                           0 /* handle */);
+       map->pages[pgnr].pte_maddr = pte_maddr;
+
        return 0;
 }
 
 static int map_grant_pages(struct grant_map *map)
 {
-       int i, err = 0;
+       int i, flags, err = 0;
+       struct gnttab_map_grant_ref* map_ops;
 
+       flags = GNTMAP_host_map | GNTMAP_application_map | GNTMAP_contains_pte;
+       if (map->is_ro)
+               flags |= GNTMAP_readonly;
+
+       map_ops = kzalloc(sizeof(map_ops[0]) * map->count, GFP_TEMPORARY);
+       if (!map_ops)
+               return -ENOMEM;
+       
+       for(i=0; i < map->count; i++)
+               gnttab_set_map_op(&map_ops[i], map->pages[i].pte_maddr, flags,
+                                 map->pages[i].target.ref,
+                                 map->pages[i].target.domid);
        if (debug)
                printk("%s: map %d+%d\n", __FUNCTION__, map->index, map->count);
        err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
-                                       map->map_ops, map->count);
+                                       map_ops, map->count);
        if (WARN_ON(err))
-               return err;
+               goto out;
 
        for (i = 0; i < map->count; i++) {
-               if (map->map_ops[i].status)
+               if (map_ops[i].status) {
+                       map->pages[i].pte_maddr = 0;
                        err = -EINVAL;
-               map->unmap_ops[i].handle = map->map_ops[i].handle;
+               } else {
+                       map->pages[i].handle = map_ops[i].handle;
+               }
        }
+
+out:
+       kfree(map_ops); 
        return err;
 }
 
-static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
+static void unmap_grant_pages(struct grant_map *map, int offset, int pages)
 {
-       int i, err = 0;
+       int i, flags, err = 0;
+       struct gnttab_unmap_grant_ref *unmap_ops;
+       struct gnttab_unmap_grant_ref unmap_single;
+
+       if (pages > 1) {
+               unmap_ops = kzalloc(sizeof(unmap_ops[0]) * pages,
+                                   GFP_TEMPORARY);
+               if (unlikely(!unmap_ops)) {
+                       for(i=0; i < pages; i++)
+                               unmap_grant_pages(map, offset + i, 1);
+                       return;
+               }
+       } else {
+               unmap_ops = &unmap_single;
+       }
 
+       flags = GNTMAP_host_map | GNTMAP_application_map | GNTMAP_contains_pte;
+       if (map->is_ro)
+               flags |= GNTMAP_readonly;
+       
+       for(i=0; i < pages; i++)
+               gnttab_set_unmap_op(&unmap_ops[i],
+                                   map->pages[offset+i].pte_maddr, flags,
+                                   map->pages[offset+i].handle);
        if (debug)
                printk("%s: map %d+%d [%d+%d]\n", __FUNCTION__,
                       map->index, map->count, offset, pages);
        err = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
-                                       map->unmap_ops + offset, pages);
+                                       unmap_ops, pages);
        if (WARN_ON(err))
-               return err;
+               goto out;
 
        for (i = 0; i < pages; i++) {
-               if (map->unmap_ops[offset+i].status)
-                       err = -EINVAL;
-               map->unmap_ops[offset+i].handle = 0;
+               WARN_ON(unmap_ops[i].status);
+               map->pages[offset+i].pte_maddr = 0;
+               map->pages[offset+i].handle = 0;
        }
-       return err;
+out:
+       if (unmap_ops != &unmap_single)
+               kfree(unmap_ops);
 }
 
 /* ------------------------------------------------------------------ */
@@ -282,7 +316,6 @@ static void mn_invl_range_start(struct mmu_notifier *mn,
        struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
        struct grant_map *map;
        unsigned long mstart, mend;
-       int err;
 
        spin_lock(&priv->lock);
        list_for_each_entry(map, &priv->maps, next) {
@@ -301,10 +334,9 @@ static void mn_invl_range_start(struct mmu_notifier *mn,
                               __FUNCTION__, map->index, map->count,
                               map->vma->vm_start, map->vma->vm_end,
                               start, end, mstart, mend);
-               err = unmap_grant_pages(map,
-                                       (mstart - map->vma->vm_start) >> 
PAGE_SHIFT,
-                                       (mend - mstart) >> PAGE_SHIFT);
-               WARN_ON(err);
+               unmap_grant_pages(map,
+                                 (mstart - map->vma->vm_start) >> PAGE_SHIFT,
+                                 (mend - mstart) >> PAGE_SHIFT);
        }
        spin_unlock(&priv->lock);
 }
@@ -321,7 +353,6 @@ static void mn_release(struct mmu_notifier *mn,
 {
        struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
        struct grant_map *map;
-       int err;
 
        spin_lock(&priv->lock);
        list_for_each_entry(map, &priv->maps, next) {
@@ -331,8 +362,7 @@ static void mn_release(struct mmu_notifier *mn,
                        printk("%s: map %d+%d (%lx %lx)\n",
                               __FUNCTION__, map->index, map->count,
                               map->vma->vm_start, map->vma->vm_end);
-               err = unmap_grant_pages(map, 0, map->count);
-               WARN_ON(err);
+               unmap_grant_pages(map, 0, map->count);
        }
        spin_unlock(&priv->lock);
 }
@@ -401,6 +431,7 @@ static long gntdev_ioctl_map_grant_ref(struct gntdev_priv 
*priv,
 {
        struct ioctl_gntdev_map_grant_ref op;
        struct grant_map *map;
+       struct ioctl_gntdev_grant_ref* grants;
        int err;
 
        if (copy_from_user(&op, u, sizeof(op)) != 0)
@@ -411,38 +442,45 @@ static long gntdev_ioctl_map_grant_ref(struct gntdev_priv 
*priv,
        if (unlikely(op.count <= 0))
                return -EINVAL;
 
+       grants = kmalloc(sizeof(grants[0]) * op.count, GFP_TEMPORARY);
+       if (!grants)
+               return -ENOMEM;
+       
+       if (copy_from_user(grants, u->refs, sizeof(grants[0]) * op.count)) {
+               err = -EFAULT;
+               goto out_free;
+       }
+
        err = -ENOMEM;
-       map = gntdev_alloc_map(priv, op.count);
+       map = gntdev_alloc_map(op.count, grants);
        if (!map)
-               return err;
-
-       if (copy_from_user(map->grants, &u->refs,
-                          sizeof(map->grants[0]) * op.count) != 0) {
-               gntdev_free_map(map);
-               return err;
-       }
+               goto out_free;
 
        if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit))
        {
                if (debug)
                        printk("%s: can't map: over limit\n", __FUNCTION__);
-               gntdev_free_map(map);
-               return err;
+               goto out_free_map;
        }
 
-       spin_lock(&priv->lock);
        gntdev_add_map(priv, map);
        op.index = map->index << PAGE_SHIFT;
-       spin_unlock(&priv->lock);
 
-       if (copy_to_user(u, &op, sizeof(op)) != 0) {
-               spin_lock(&priv->lock);
-               gntdev_del_map(map);
-               spin_unlock(&priv->lock);
-               gntdev_free_map(map);
-               return err;
+       if (copy_to_user(u, &op, sizeof(op))) {
+               err = -EFAULT;
+               goto out_remove;
        }
-       return 0;
+       err = 0;
+out_free:
+       kfree(grants);
+       return err;
+out_remove:
+       spin_lock(&priv->lock);
+       gntdev_del_map(map);
+       spin_unlock(&priv->lock);
+out_free_map:
+       gntdev_free_map(map);
+       goto out_free;
 }
 
 static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
@@ -556,10 +594,7 @@ static int gntdev_mmap(struct file *flip, struct 
vm_area_struct *vma)
 
        vma->vm_private_data = map;
        map->vma = vma;
-
-       map->flags = GNTMAP_host_map | GNTMAP_application_map | 
GNTMAP_contains_pte;
-       if (!(vma->vm_flags & VM_WRITE))
-               map->flags |= GNTMAP_readonly;
+       map->is_ro = !(vma->vm_flags & VM_WRITE);
 
        spin_unlock(&priv->lock);
 
-- 
1.7.2.3


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