[Xen-devel] [PATCHv4 10/14] xen/gntdev: convert priv->lock to a mutex

[David Vrabel <david.vrabel@xxxxxxxxxx>]

Unmapping may require sleeping and we unmap while holding priv->lock, so
convert it to a mutex.

Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
 drivers/xen/gntdev.c |   40 ++++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index a28807a..c1a03fa 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -67,7 +67,7 @@ struct gntdev_priv {
         * Only populated if populate_freeable_maps == 1 */
        struct list_head freeable_maps;
        /* lock protects maps and freeable_maps */
-       spinlock_t lock;
+       struct mutex lock;
        struct mm_struct *mm;
        struct mmu_notifier mn;
 };
@@ -221,9 +221,9 @@ static void gntdev_put_map(struct gntdev_priv *priv, struct 
grant_map *map)
        }
 
        if (populate_freeable_maps && priv) {
-               spin_lock(&priv->lock);
+               mutex_lock(&priv->lock);
                list_del(&map->next);
-               spin_unlock(&priv->lock);
+               mutex_unlock(&priv->lock);
        }
 
        if (map->pages && !use_ptemod)
@@ -397,9 +397,9 @@ static void gntdev_vma_close(struct vm_area_struct *vma)
                 * not do any unmapping, since that has been done prior to
                 * closing the vma, but it may still iterate the unmap_ops list.
                 */
-               spin_lock(&priv->lock);
+               mutex_lock(&priv->lock);
                map->vma = NULL;
-               spin_unlock(&priv->lock);
+               mutex_unlock(&priv->lock);
        }
        vma->vm_private_data = NULL;
        gntdev_put_map(priv, map);
@@ -443,14 +443,14 @@ 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;
 
-       spin_lock(&priv->lock);
+       mutex_lock(&priv->lock);
        list_for_each_entry(map, &priv->maps, next) {
                unmap_if_in_range(map, start, end);
        }
        list_for_each_entry(map, &priv->freeable_maps, next) {
                unmap_if_in_range(map, start, end);
        }
-       spin_unlock(&priv->lock);
+       mutex_unlock(&priv->lock);
 }
 
 static void mn_invl_page(struct mmu_notifier *mn,
@@ -467,7 +467,7 @@ static void mn_release(struct mmu_notifier *mn,
        struct grant_map *map;
        int err;
 
-       spin_lock(&priv->lock);
+       mutex_lock(&priv->lock);
        list_for_each_entry(map, &priv->maps, next) {
                if (!map->vma)
                        continue;
@@ -486,7 +486,7 @@ static void mn_release(struct mmu_notifier *mn,
                err = unmap_grant_pages(map, /* offset */ 0, map->count);
                WARN_ON(err);
        }
-       spin_unlock(&priv->lock);
+       mutex_unlock(&priv->lock);
 }
 
 static struct mmu_notifier_ops gntdev_mmu_ops = {
@@ -508,7 +508,7 @@ static int gntdev_open(struct inode *inode, struct file 
*flip)
 
        INIT_LIST_HEAD(&priv->maps);
        INIT_LIST_HEAD(&priv->freeable_maps);
-       spin_lock_init(&priv->lock);
+       mutex_init(&priv->lock);
 
        if (use_ptemod) {
                priv->mm = get_task_mm(current);
@@ -582,10 +582,10 @@ static long gntdev_ioctl_map_grant_ref(struct gntdev_priv 
*priv,
                return -EFAULT;
        }
 
-       spin_lock(&priv->lock);
+       mutex_lock(&priv->lock);
        gntdev_add_map(priv, map);
        op.index = map->index << PAGE_SHIFT;
-       spin_unlock(&priv->lock);
+       mutex_unlock(&priv->lock);
 
        if (copy_to_user(u, &op, sizeof(op)) != 0)
                return -EFAULT;
@@ -604,7 +604,7 @@ static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv 
*priv,
                return -EFAULT;
        pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
 
-       spin_lock(&priv->lock);
+       mutex_lock(&priv->lock);
        map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
        if (map) {
                list_del(&map->next);
@@ -612,7 +612,7 @@ static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv 
*priv,
                        list_add_tail(&map->next, &priv->freeable_maps);
                err = 0;
        }
-       spin_unlock(&priv->lock);
+       mutex_unlock(&priv->lock);
        if (map)
                gntdev_put_map(priv, map);
        return err;
@@ -680,7 +680,7 @@ static long gntdev_ioctl_notify(struct gntdev_priv *priv, 
void __user *u)
        out_flags = op.action;
        out_event = op.event_channel_port;
 
-       spin_lock(&priv->lock);
+       mutex_lock(&priv->lock);
 
        list_for_each_entry(map, &priv->maps, next) {
                uint64_t begin = map->index << PAGE_SHIFT;
@@ -708,7 +708,7 @@ static long gntdev_ioctl_notify(struct gntdev_priv *priv, 
void __user *u)
        rc = 0;
 
  unlock_out:
-       spin_unlock(&priv->lock);
+       mutex_unlock(&priv->lock);
 
        /* Drop the reference to the event channel we did not save in the map */
        if (out_flags & UNMAP_NOTIFY_SEND_EVENT)
@@ -758,7 +758,7 @@ static int gntdev_mmap(struct file *flip, struct 
vm_area_struct *vma)
        pr_debug("map %d+%d at %lx (pgoff %lx)\n",
                        index, count, vma->vm_start, vma->vm_pgoff);
 
-       spin_lock(&priv->lock);
+       mutex_lock(&priv->lock);
        map = gntdev_find_map_index(priv, index, count);
        if (!map)
                goto unlock_out;
@@ -793,7 +793,7 @@ static int gntdev_mmap(struct file *flip, struct 
vm_area_struct *vma)
                        map->flags |= GNTMAP_readonly;
        }
 
-       spin_unlock(&priv->lock);
+       mutex_unlock(&priv->lock);
 
        if (use_ptemod) {
                err = apply_to_page_range(vma->vm_mm, vma->vm_start,
@@ -821,11 +821,11 @@ static int gntdev_mmap(struct file *flip, struct 
vm_area_struct *vma)
        return 0;
 
 unlock_out:
-       spin_unlock(&priv->lock);
+       mutex_unlock(&priv->lock);
        return err;
 
 out_unlock_put:
-       spin_unlock(&priv->lock);
+       mutex_unlock(&priv->lock);
 out_put_map:
        if (use_ptemod)
                map->vma = NULL;
-- 
1.7.10.4


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