[PATCH 10/15] habanalabs: fix memory leak with CBs with unaligned size

[Oded Gabbay]

This patch fix a bug when a command buffer with unaligned size (with
regard to PAGE_SIZE) was used. The accounting for the unmap operation
wasn't done correctly and could result in a memory leak.

Signed-off-by: Oded Gabbay <oded.gab...@gmail.com>
---
 drivers/misc/habanalabs/command_buffer.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/misc/habanalabs/command_buffer.c 
b/drivers/misc/habanalabs/command_buffer.c
index 28e359731fb8..85f75806a9a7 100644
--- a/drivers/misc/habanalabs/command_buffer.c
+++ b/drivers/misc/habanalabs/command_buffer.c
@@ -236,11 +236,14 @@ int hl_cb_ioctl(struct hl_fpriv *hpriv, void *data)
 static void cb_vm_close(struct vm_area_struct *vma)
 {
        struct hl_cb *cb = (struct hl_cb *) vma->vm_private_data;
+       long new_mmap_size;
 
-       cb->mmap_size -= vma->vm_end - vma->vm_start;
+       new_mmap_size = cb->mmap_size - (vma->vm_end - vma->vm_start);
 
-       if (cb->mmap_size)
+       if (new_mmap_size > 0) {
+               cb->mmap_size = new_mmap_size;
                return;
+       }
 
        spin_lock(&cb->lock);
        cb->mmap = false;
@@ -273,7 +276,7 @@ int hl_cb_mmap(struct hl_fpriv *hpriv, struct 
vm_area_struct *vma)
        }
 
        /* Validation check */
-       if ((vma->vm_end - vma->vm_start) != cb->size) {
+       if ((vma->vm_end - vma->vm_start) != ALIGN(cb->size, PAGE_SIZE)) {
                dev_err(hdev->dev,
                        "CB mmap failed, mmap size 0x%lx != 0x%x cb size\n",
                        vma->vm_end - vma->vm_start, cb->size);
-- 
2.17.1