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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCHv4 10/14] xen/gntdev: convert priv->lock to a mutex
On Mon, 26 Jan 2015, David Vrabel wrote:
> 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);
> }
I don't think that mmu_notifier callbacks are allowed to sleep:
https://lkml.org/lkml/2010/1/25/187
> 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
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel
>
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