scsi: sg: sg_new_write(): replace access_ok() + __copy_from_user() with copy_from_user()

Link: https://lore.kernel.org/r/20191017193925.25539-2-viro@ZenIV.linux.org.ukSigned-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/sg.c

@@ -763,11 +763,7 @@ sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
 		sg_remove_request(sfp, srp);
 		return -EMSGSIZE;
 	}
-	if (!access_ok(hp->cmdp, hp->cmd_len)) {
-		sg_remove_request(sfp, srp);
-		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
-	}
-	if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
+	if (copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
 		sg_remove_request(sfp, srp);
 		return -EFAULT;
 	}