Re: [PATCH] um: NULL check before kfree is not needed

[Anton Ivanov]

On 03/08/18 07:39, YueHaibing wrote:

kfree(NULL) is safe,so this removes NULL check before freeing the mem
Signed-off-by: YueHaibing <yuehaib...@huawei.com>
---
  arch/um/drivers/vector_kern.c | 15 +++++----------
  arch/um/drivers/vector_user.c |  6 ++----
  arch/um/kernel/irq.c          |  3 +--
  3 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_kern.c
index 50ee3bb..c84133c 100644
--- a/arch/um/drivers/vector_kern.c
+++ b/arch/um/drivers/vector_kern.c
@@ -1118,16 +1118,11 @@ static int vector_net_close(struct net_device *dev)
                os_close_file(vp->fds->tx_fd);
                vp->fds->tx_fd = -1;
        }
-       if (vp->bpf != NULL)
-               kfree(vp->bpf);
-       if (vp->fds->remote_addr != NULL)
-               kfree(vp->fds->remote_addr);
-       if (vp->transport_data != NULL)
-               kfree(vp->transport_data);
-       if (vp->header_rxbuffer != NULL)
-               kfree(vp->header_rxbuffer);
-       if (vp->header_txbuffer != NULL)
-               kfree(vp->header_txbuffer);
+       kfree(vp->bpf);
+       kfree(vp->fds->remote_addr);
+       kfree(vp->transport_data);
+       kfree(vp->header_rxbuffer);
+       kfree(vp->header_txbuffer);
        if (vp->rx_queue != NULL)
                destroy_queue(vp->rx_queue);
        if (vp->tx_queue != NULL)
diff --git a/arch/um/drivers/vector_user.c b/arch/um/drivers/vector_user.c
index 4d6a78e..3d8cdbd 100644
--- a/arch/um/drivers/vector_user.c
+++ b/arch/um/drivers/vector_user.c
@@ -267,8 +267,7 @@ static struct vector_fds *user_init_raw_fds(struct arglist 
*ifspec)
                os_close_file(rxfd);
        if (txfd >= 0)
                os_close_file(txfd);
-       if (result != NULL)
-               kfree(result);
+       kfree(result);
        return NULL;
  }
  
@@ -434,8 +433,7 @@ static struct vector_fds *user_init_socket_fds(struct arglist *ifspec, int id)
        if (fd >= 0)
                os_close_file(fd);
        if (result != NULL) {
-               if (result->remote_addr != NULL)
-                       kfree(result->remote_addr);
+               kfree(result->remote_addr);
                kfree(result);
        }
        return NULL;
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index 6b7f382..8360fa3 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -244,8 +244,7 @@ static void garbage_collect_irq_entries(void)
                        to_free = NULL;
                }
                walk = walk->next;
-               if (to_free != NULL)
-                       kfree(to_free);
+               kfree(to_free);
        }
  }
  
kfree in both slab and slob check for NULLs before freeing so this is 
correct. Thanks for noticing.

Richard, please apply,

A.