linux-kernel - [PATCH 2/3] habanalabs: clear vm

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Date:   Sat, 29 Aug 2020 17:43:51 +0300
From:   Oded Gabbay <oded.gabbay@...il.com>
To:     linux-kernel@...r.kernel.org, SW_Drivers@...ana.ai
Subject: [PATCH 2/3] habanalabs: clear vm_pgoff before doing the mmap

The driver use vm_pgoff to hold the CB idr handle. Before we actually call
the mapping function, we need to clear the handle so there won't be any
garbage left in vm_pgoff.

Signed-off-by: Oded Gabbay <oded.gabbay@...il.com>
---
 drivers/misc/habanalabs/common/command_buffer.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/misc/habanalabs/common/command_buffer.c b/drivers/misc/habanalabs/common/command_buffer.c
index 68dfbafe3354..6563e4dfe7b6 100644
--- a/drivers/misc/habanalabs/common/command_buffer.c
+++ b/drivers/misc/habanalabs/common/command_buffer.c
@@ -304,7 +304,11 @@ int hl_cb_mmap(struct hl_fpriv *hpriv, struct vm_area_struct *vma)
 	u32 handle, user_cb_size;
 	int rc;
 
+	/* We use the page offset to hold the idr and thus we need to clear
+	 * it before doing the mmap itself
+	 */
 	handle = vma->vm_pgoff;
+	vma->vm_pgoff = 0;
 
 	/* reference was taken here */
 	cb = hl_cb_get(hdev, &hpriv->cb_mgr, handle);
-- 
2.17.1