2009-12-19 07:30:18

by Julia Lawall

Subject: [PATCH 1/2] drivers/block: drop unnecesary memset

From: Julia Lawall <[email protected]>

memset of 0 is not needed after kzalloc

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression x;
statement S;
@@

x = kzalloc(...);
if (x == NULL) S
... when != x
-memset(x,0,...);// </smpl>

Signed-off-by: Julia Lawall <[email protected]>

---
drivers/block/cciss.c | 1 -
1 file changed, 1 deletion(-)

diff -u -p a/drivers/block/cciss.c b/drivers/block/cciss.c
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -4379,7 +4379,6 @@ static void cciss_shutdown(struct pci_de
return;
}
/* write all data in the battery backed cache to disk */
- memset(flush_buf, 0, 4);
return_code = sendcmd_withirq(CCISS_CACHE_FLUSH, h->ctlr, flush_buf,
4, 0, CTLR_LUNID, TYPE_CMD);
kfree(flush_buf);

2010-01-04 16:15:25

by Mike Miller

Subject: RE: [PATCH 1/2] drivers/block: drop unnecesary memset

> -----Original Message-----
> From: Julia Lawall [mailto:[email protected]]
> Sent: Saturday, December 19, 2009 1:30 AM
> To: Miller, Mike (OS Dev); ISS StorageDev;
> [email protected]; [email protected]
> Subject: [PATCH 1/2] drivers/block: drop unnecesary memset
>
> From: Julia Lawall <[email protected]>
>
> memset of 0 is not needed after kzalloc
>
> The semantic patch that makes this change is as follows:
> (http://coccinelle.lip6.fr/)
>
> // <smpl>
> @@
> expression x;
> statement S;
> @@
>
> x = kzalloc(...);
> if (x == NULL) S
> ... when != x
> -memset(x,0,...);// </smpl>
>
> Signed-off-by: Julia Lawall <[email protected]>

Acked-by: Mike Miller <[email protected]>

>
> ---
> drivers/block/cciss.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff -u -p a/drivers/block/cciss.c b/drivers/block/cciss.c
> --- a/drivers/block/cciss.c
> +++ b/drivers/block/cciss.c
> @@ -4379,7 +4379,6 @@ static void cciss_shutdown(struct pci_de
> return;
> }
> /* write all data in the battery backed cache to disk */
> - memset(flush_buf, 0, 4);
> return_code = sendcmd_withirq(CCISS_CACHE_FLUSH,
> h->ctlr, flush_buf,
> 4, 0, CTLR_LUNID, TYPE_CMD);
> kfree(flush_buf);
> -