linux-kernel - [PATCH] um: NULL check before kfree is not needed

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Date:   Fri, 3 Aug 2018 14:39:11 +0800
From:   YueHaibing <yuehaibing@...wei.com>
To:     <jdike@...toit.com>, <richard@....at>,
        <anton.ivanov@...bridgegreys.com>, <christophe.jaillet@...adoo.fr>,
        <keescook@...omium.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-um@...ts.infradead.org>,
        YueHaibing <yuehaibing@...wei.com>
Subject: [PATCH] um: NULL check before kfree is not needed

kfree(NULL) is safe,so this removes NULL check before freeing the mem

Signed-off-by: YueHaibing <yuehaibing@...wei.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);
 	}
 }
 
-- 
2.7.0