From 8ca19a8937ad91703cfefccf13bd8017b39510cd Mon Sep 17 00:00:00 2001 From: Daniel De Graaf Date: Thu, 27 Oct 2011 17:58:48 -0400 Subject: [PATCH] xen/gntalloc: Change gref_lock to a mutex The event channel release function cannot be called under a spinlock because it can attempt to acquire a mutex due to the event channel reference acquired when setting up unmap notifications. Signed-off-by: Daniel De Graaf Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/gntalloc.c | 41 +++++++++++++++++++++-------------------- 1 file changed, 21 insertions(+), 20 deletions(-) diff --git a/drivers/xen/gntalloc.c b/drivers/xen/gntalloc.c index f6832f4..439352d 100644 --- a/drivers/xen/gntalloc.c +++ b/drivers/xen/gntalloc.c @@ -74,7 +74,7 @@ MODULE_PARM_DESC(limit, "Maximum number of grants that may be allocated by " "the gntalloc device"); static LIST_HEAD(gref_list); -static DEFINE_SPINLOCK(gref_lock); +static DEFINE_MUTEX(gref_mutex); static int gref_size; struct notify_info { @@ -143,15 +143,15 @@ static int add_grefs(struct ioctl_gntalloc_alloc_gref *op, } /* Add to gref lists. */ - spin_lock(&gref_lock); + mutex_lock(&gref_mutex); list_splice_tail(&queue_gref, &gref_list); list_splice_tail(&queue_file, &priv->list); - spin_unlock(&gref_lock); + mutex_unlock(&gref_mutex); return 0; undo: - spin_lock(&gref_lock); + mutex_lock(&gref_mutex); gref_size -= (op->count - i); list_for_each_entry(gref, &queue_file, next_file) { @@ -167,7 +167,7 @@ undo: */ if (unlikely(!list_empty(&queue_gref))) list_splice_tail(&queue_gref, &gref_list); - spin_unlock(&gref_lock); + mutex_unlock(&gref_mutex); return rc; } @@ -251,7 +251,7 @@ static int gntalloc_release(struct inode *inode, struct file *filp) pr_debug("%s: priv %p\n", __func__, priv); - spin_lock(&gref_lock); + mutex_lock(&gref_mutex); while (!list_empty(&priv->list)) { gref = list_entry(priv->list.next, struct gntalloc_gref, next_file); @@ -261,7 +261,7 @@ static int gntalloc_release(struct inode *inode, struct file *filp) __del_gref(gref); } kfree(priv); - spin_unlock(&gref_lock); + mutex_unlock(&gref_mutex); return 0; } @@ -286,21 +286,21 @@ static long gntalloc_ioctl_alloc(struct gntalloc_file_private_data *priv, goto out; } - spin_lock(&gref_lock); + mutex_lock(&gref_mutex); /* Clean up pages that were at zero (local) users but were still mapped * by remote domains. Since those pages count towards the limit that we * are about to enforce, removing them here is a good idea. */ do_cleanup(); if (gref_size + op.count > limit) { - spin_unlock(&gref_lock); + mutex_unlock(&gref_mutex); rc = -ENOSPC; goto out_free; } gref_size += op.count; op.index = priv->index; priv->index += op.count * PAGE_SIZE; - spin_unlock(&gref_lock); + mutex_unlock(&gref_mutex); rc = add_grefs(&op, gref_ids, priv); if (rc < 0) @@ -343,7 +343,7 @@ static long gntalloc_ioctl_dealloc(struct gntalloc_file_private_data *priv, goto dealloc_grant_out; } - spin_lock(&gref_lock); + mutex_lock(&gref_mutex); gref = find_grefs(priv, op.index, op.count); if (gref) { /* Remove from the file list only, and decrease reference count. @@ -363,7 +363,7 @@ static long gntalloc_ioctl_dealloc(struct gntalloc_file_private_data *priv, do_cleanup(); - spin_unlock(&gref_lock); + mutex_unlock(&gref_mutex); dealloc_grant_out: return rc; } @@ -383,7 +383,7 @@ static long gntalloc_ioctl_unmap_notify(struct gntalloc_file_private_data *priv, index = op.index & ~(PAGE_SIZE - 1); pgoff = op.index & (PAGE_SIZE - 1); - spin_lock(&gref_lock); + mutex_lock(&gref_mutex); gref = find_grefs(priv, index, 1); if (!gref) { @@ -400,8 +400,9 @@ static long gntalloc_ioctl_unmap_notify(struct gntalloc_file_private_data *priv, gref->notify.pgoff = pgoff; gref->notify.event = op.event_channel_port; rc = 0; + unlock_out: - spin_unlock(&gref_lock); + mutex_unlock(&gref_mutex); return rc; } @@ -433,9 +434,9 @@ static void gntalloc_vma_open(struct vm_area_struct *vma) if (!gref) return; - spin_lock(&gref_lock); + mutex_lock(&gref_mutex); gref->users++; - spin_unlock(&gref_lock); + mutex_unlock(&gref_mutex); } static void gntalloc_vma_close(struct vm_area_struct *vma) @@ -444,11 +445,11 @@ static void gntalloc_vma_close(struct vm_area_struct *vma) if (!gref) return; - spin_lock(&gref_lock); + mutex_lock(&gref_mutex); gref->users--; if (gref->users == 0) __del_gref(gref); - spin_unlock(&gref_lock); + mutex_unlock(&gref_mutex); } static struct vm_operations_struct gntalloc_vmops = { @@ -471,7 +472,7 @@ static int gntalloc_mmap(struct file *filp, struct vm_area_struct *vma) return -EINVAL; } - spin_lock(&gref_lock); + mutex_lock(&gref_mutex); gref = find_grefs(priv, vma->vm_pgoff << PAGE_SHIFT, count); if (gref == NULL) { rv = -ENOENT; @@ -499,7 +500,7 @@ static int gntalloc_mmap(struct file *filp, struct vm_area_struct *vma) rv = 0; out_unlock: - spin_unlock(&gref_lock); + mutex_unlock(&gref_mutex); return rv; } -- 2.7.4