[PATCH 3.10 23/56] xen/gntdev: convert priv->lock to a mutex

From: Greg Kroah-Hartman
Date: Tue Sep 29 2015 - 09:49:08 EST


3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: David Vrabel <david.vrabel@xxxxxxxxxx>

commit 1401c00e59ea021c575f74612fe2dbba36d6a4ee upstream.

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>
Reviewed-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Cc: Ian Campbell <ian.campbell@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/xen/gntdev.c | 40 ++++++++++++++++++++--------------------
1 file changed, 20 insertions(+), 20 deletions(-)

--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -65,7 +65,7 @@ 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;
};
@@ -214,9 +214,9 @@ static void gntdev_put_map(struct gntdev
}

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)
@@ -392,9 +392,9 @@ static void gntdev_vma_close(struct vm_a
* 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);
@@ -438,14 +438,14 @@ static void mn_invl_range_start(struct m
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,
@@ -462,7 +462,7 @@ static void mn_release(struct mmu_notifi
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;
@@ -481,7 +481,7 @@ static void mn_release(struct mmu_notifi
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 = {
@@ -503,7 +503,7 @@ static int gntdev_open(struct inode *ino

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);
@@ -579,10 +579,10 @@ static long gntdev_ioctl_map_grant_ref(s
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;
@@ -601,7 +601,7 @@ static long gntdev_ioctl_unmap_grant_ref
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);
@@ -609,7 +609,7 @@ static long gntdev_ioctl_unmap_grant_ref
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;
@@ -677,7 +677,7 @@ static long gntdev_ioctl_notify(struct g
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;
@@ -705,7 +705,7 @@ static long gntdev_ioctl_notify(struct g
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)
@@ -755,7 +755,7 @@ static int gntdev_mmap(struct file *flip
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;
@@ -790,7 +790,7 @@ static int gntdev_mmap(struct file *flip
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,
@@ -818,11 +818,11 @@ static int gntdev_mmap(struct file *flip
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;


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