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>

diff --git a/drivers/infiniband/hw/efa/efa_verbs.c b/drivers/infiniband/hw/efa/efa_verbs.c
index 0fea5d6..fb61152 100644 (file)
--- 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,