esas2r: don't open-code memdup_user()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 3 insertions, 22 deletions

diff --git a/drivers/scsi/esas2r/esas2r_ioctl.c b/drivers/scsi/esas2r/esas2r_ioctl.c
index b35ed3829421..2d4b7f049a68 100644
--- a/drivers/scsi/esas2r/esas2r_ioctl.c
+++ b/drivers/scsi/esas2r/esas2r_ioctl.c
@@ -1289,32 +1289,13 @@ int esas2r_ioctl_handler(void *hostdata, int cmd, void __user *arg)
             || (cmd > EXPRESS_IOCTL_MAX))
                 return -ENOTSUPP;
 
-        if (!access_ok(VERIFY_WRITE, arg, sizeof(struct atto_express_ioctl))) {
+        ioctl = memdup_user(arg, sizeof(struct atto_express_ioctl));
+        if (IS_ERR(ioctl)) {
                 esas2r_log(ESAS2R_LOG_WARN,
                            "ioctl_handler access_ok failed for cmd %d, "
                            "address %p", cmd,
                            arg);
-                return -EFAULT;
-        }
-
-        /* allocate a kernel memory buffer for the IOCTL data */
-        ioctl = kzalloc(sizeof(struct atto_express_ioctl), GFP_KERNEL);
-        if (ioctl == NULL) {
-                esas2r_log(ESAS2R_LOG_WARN,
-                           "ioctl_handler kzalloc failed for %zu bytes",
-                           sizeof(struct atto_express_ioctl));
-                return -ENOMEM;
-        }
-
-        err = __copy_from_user(ioctl, arg, sizeof(struct atto_express_ioctl));
-        if (err != 0) {
-                esas2r_log(ESAS2R_LOG_WARN,
-                           "copy_from_user didn't copy everything (err %d, cmd %d)",
-                           err,
-                           cmd);
-                kfree(ioctl);
-
-                return -EFAULT;
+                return PTR_ERR(ioctl);
         }
 
         /* verify the signature */