cxl: Fix error path on bad ioctl

Fix error path if we can't copy user structure on CXL_IOCTL_START_WORK
ioctl. We shouldn't unlock the context status mutex as it was not
locked (yet).

Fixes: 0712dc7e73e5 ("cxl: Fix issues when unmapping contexts")
Cc: stable@vger.kernel.org # v3.19+
Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Reviewed-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c
index 17b433f..0761271 100644 (file)
--- a/drivers/misc/cxl/file.c
+++ b/drivers/misc/cxl/file.c
@@ -159,11 +159,8 @@ static long afu_ioctl_start_work(struct cxl_context *ctx,
 
        /* Do this outside the status_mutex to avoid a circular dependency with
         * the locking in cxl_mmap_fault() */
-       if (copy_from_user(&work, uwork,
-                          sizeof(struct cxl_ioctl_start_work))) {
-               rc = -EFAULT;
-               goto out;
-       }
+       if (copy_from_user(&work, uwork, sizeof(work)))
+               return -EFAULT;
 
        mutex_lock(&ctx->status_mutex);
        if (ctx->status != OPENED) {