RDMA/efa: Handle mmap insertions overflow

When inserting a new mmap entry to the xarray we should check for
'mmap_page' overflow as it is limited to 32 bits.

Fixes: 40909f664d27 ("RDMA/efa: Add EFA verbs implementation")
Signed-off-by: Gal Pressman <galpress@amazon.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 16 insertions, 5 deletions

diff --git a/drivers/infiniband/hw/efa/efa_verbs.c b/drivers/infiniband/hw/efa/efa_verbs.c
index 0fea5d63fdbe..fb6115244d4c 100644
--- a/drivers/infiniband/hw/efa/efa_verbs.c
+++ b/drivers/infiniband/hw/efa/efa_verbs.c
@@ -204,6 +204,7 @@ static u64 mmap_entry_insert(struct efa_dev *dev, struct efa_ucontext *ucontext,
                              void *obj, u64 address, u64 length, u8 mmap_flag)
 {
         struct efa_mmap_entry *entry;
+        u32 next_mmap_page;
         int err;
 
         entry = kmalloc(sizeof(*entry), GFP_KERNEL);
@@ -216,15 +217,19 @@ static u64 mmap_entry_insert(struct efa_dev *dev, struct efa_ucontext *ucontext,
         entry->mmap_flag = mmap_flag;
 
         xa_lock(&ucontext->mmap_xa);
+        if (check_add_overflow(ucontext->mmap_xa_page,
+                               (u32)(length >> PAGE_SHIFT),
+                               &next_mmap_page))
+                goto err_unlock;
+
         entry->mmap_page = ucontext->mmap_xa_page;
-        ucontext->mmap_xa_page += DIV_ROUND_UP(length, PAGE_SIZE);
+        ucontext->mmap_xa_page = next_mmap_page;
         err = __xa_insert(&ucontext->mmap_xa, entry->mmap_page, entry,
                           GFP_KERNEL);
+        if (err)
+                goto err_unlock;
+
         xa_unlock(&ucontext->mmap_xa);
-        if (err){
-                kfree(entry);
-                return EFA_MMAP_INVALID;
-        }
 
         ibdev_dbg(
                 &dev->ibdev,
@@ -232,6 +237,12 @@ static u64 mmap_entry_insert(struct efa_dev *dev, struct efa_ucontext *ucontext,
                 entry->obj, entry->address, entry->length, get_mmap_key(entry));
 
         return get_mmap_key(entry);
+
+err_unlock:
+        xa_unlock(&ucontext->mmap_xa);
+        kfree(entry);
+        return EFA_MMAP_INVALID;
+
 }
 
 int efa_query_device(struct ib_device *ibdev,