From: Barry Song <v-songbaohua@xxxxxxxx>
mm doesn't support non-blockable __GFP_NOFAIL allocation. Because
__GFP_NOFAIL without direct reclamation may just result in a busy
loop within non-sleepable contexts.
static inline struct page *
__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
struct alloc_context *ac)
{
...
/*
* Make sure that __GFP_NOFAIL request doesn't leak out and make sure
* we always retry
*/
if (gfp_mask & __GFP_NOFAIL) {
/*
* All existing users of the __GFP_NOFAIL are blockable, so warn
* of any new users that actually require GFP_NOWAIT
*/
if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask))
goto fail;
...
}
...
fail:
warn_alloc(gfp_mask, ac->nodemask,
"page allocation failure: order:%u", order);
got_pg:
return page;
}
Let's move the memory allocation out of the atomic context and use
the normal sleepable context to get pages.
[RFT]: This has only been compile-tested; I'd prefer if the VDPA maintainers
handles it.
Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
Cc: Jason Wang <jasowang@xxxxxxxxxx>
Cc: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Cc: "Eugenio Pérez" <eperezma@xxxxxxxxxx>
Cc: Maxime Coquelin <maxime.coquelin@xxxxxxxxxx>
Signed-off-by: Barry Song <v-songbaohua@xxxxxxxx>
---
drivers/vdpa/vdpa_user/iova_domain.c | 31 +++++++++++++++++++++++-----
drivers/vdpa/vdpa_user/iova_domain.h | 5 ++++-
drivers/vdpa/vdpa_user/vduse_dev.c | 4 +++-
3 files changed, 33 insertions(+), 7 deletions(-)
diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c
index 791d38d6284c..9318f059a8b5 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.c
+++ b/drivers/vdpa/vdpa_user/iova_domain.c
@@ -283,7 +283,23 @@ int vduse_domain_add_user_bounce_pages(struct vduse_iova_domain *domain,
return ret;
}
-void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain)
+struct page **vduse_domain_alloc_pages_to_remove_bounce(struct vduse_iova_domain *domain)
+{
+ struct page **pages;
+ unsigned long count, i;
+
+ if (!domain->user_bounce_pages)
+ return NULL;
+
+ count = domain->bounce_size >> PAGE_SHIFT;
+ pages = kmalloc_array(count, sizeof(*pages), GFP_KERNEL | __GFP_NOFAIL);
+ for (i = 0; i < count; i++)
+ pages[i] = alloc_page(GFP_KERNEL | __GFP_NOFAIL);
+
+ return pages;
+}
+
+void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain, struct page **pages)
{
struct vduse_bounce_map *map;
unsigned long i, count;
@@ -294,15 +310,16 @@ void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain)
count = domain->bounce_size >> PAGE_SHIFT;
for (i = 0; i < count; i++) {
- struct page *page = NULL;
+ struct page *page = pages[i];
map = &domain->bounce_maps[i];
- if (WARN_ON(!map->bounce_page))
+ if (WARN_ON(!map->bounce_page)) {
+ put_page(page);
continue;
+ }
/* Copy user page to kernel page if it's in use */
if (map->orig_phys != INVALID_PHYS_ADDR) {
- page = alloc_page(GFP_ATOMIC | __GFP_NOFAIL);
memcpy_from_page(page_address(page),
map->bounce_page, 0, PAGE_SIZE);
}
@@ -310,6 +327,7 @@ void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain)
map->bounce_page = page;
}
domain->user_bounce_pages = false;
+ kfree(pages);
out:
write_unlock(&domain->bounce_lock);
}
@@ -543,10 +561,13 @@ static int vduse_domain_mmap(struct file *file, struct vm_area_struct *vma)
static int vduse_domain_release(struct inode *inode, struct file *file)
{
struct vduse_iova_domain *domain = file->private_data;
+ struct page **pages;
+
+ pages = vduse_domain_alloc_pages_to_remove_bounce(domain);
spin_lock(&domain->iotlb_lock);
vduse_iotlb_del_range(domain, 0, ULLONG_MAX);
- vduse_domain_remove_user_bounce_pages(domain);
+ vduse_domain_remove_user_bounce_pages(domain, pages);
vduse_domain_free_kernel_bounce_pages(domain);
spin_unlock(&domain->iotlb_lock);
put_iova_domain(&domain->stream_iovad);
diff --git a/drivers/vdpa/vdpa_user/iova_domain.h b/drivers/vdpa/vdpa_user/iova_domain.h
index f92f22a7267d..17efa5555b3f 100644
--- a/drivers/vdpa/vdpa_user/iova_domain.h
+++ b/drivers/vdpa/vdpa_user/iova_domain.h
@@ -74,7 +74,10 @@ void vduse_domain_reset_bounce_map(struct vduse_iova_domain *domain);
int vduse_domain_add_user_bounce_pages(struct vduse_iova_domain *domain,
struct page **pages, int count);
-void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain);
+void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain,
+ struct page **pages);
+
+struct page **vduse_domain_alloc_pages_to_remove_bounce(struct vduse_iova_domain *domain);
void vduse_domain_destroy(struct vduse_iova_domain *domain);
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 7ae99691efdf..5d8d5810df57 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -1030,6 +1030,7 @@ static int vduse_dev_queue_irq_work(struct vduse_dev *dev,
static int vduse_dev_dereg_umem(struct vduse_dev *dev,
u64 iova, u64 size)
{
+ struct page **pages;
int ret;
mutex_lock(&dev->mem_lock);
@@ -1044,7 +1045,8 @@ static int vduse_dev_dereg_umem(struct vduse_dev *dev,
if (dev->umem->iova != iova || size != dev->domain->bounce_size)
goto unlock;
- vduse_domain_remove_user_bounce_pages(dev->domain);
+ pages = vduse_domain_alloc_pages_to_remove_bounce(dev->domain);
+ vduse_domain_remove_user_bounce_pages(dev->domain, pages);
unpin_user_pages_dirty_lock(dev->umem->pages,
dev->umem->npages, true);
atomic64_sub(dev->umem->npages, &dev->umem->mm->pinned_vm);
--
2.34.1
