Syslinux - Sep 2013 - [PATCH 1/4 v2] com32/lib/: Avoid unneeded allocation.

eparam would only be used if EBIOS is available.
If it is not, then there is no reason to allocate eparam.

Signed-off-by: Raphael S.Carvalho <raphael.scarv at gmail.com>
---
 com32/lib/syslinux/disk.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/com32/lib/syslinux/disk.c b/com32/lib/syslinux/disk.c
index 093751a..d96acbf 100644
--- a/com32/lib/syslinux/disk.c
+++ b/com32/lib/syslinux/disk.c
@@ -73,7 +73,7 @@ int disk_int13_retry(const com32sys_t * inreg, com32sys_t *
outreg)
 int disk_get_params(int disk, struct disk_info *const diskinfo)
 {
     static com32sys_t inreg, outreg;
-    struct disk_ebios_eparam *eparam;
+    struct disk_ebios_eparam *eparam = NULL;
     int rv = 0;

     memset(diskinfo, 0, sizeof *diskinfo);
@@ -94,12 +94,12 @@ int disk_get_params(int disk, struct disk_info *const
diskinfo)
 	diskinfo->ebios = 1;
     }

-    eparam = lmalloc(sizeof *eparam);
-    if (!eparam)
-	return -1;
-
     /* Get extended disk parameters if ebios == 1 */
     if (diskinfo->ebios) {
+	eparam = lmalloc(sizeof *eparam);
+	if (!eparam)
+	    return -1;
+
 	memset(&inreg, 0, sizeof inreg);
 	inreg.eax.b[1] = 0x48;
 	inreg.edx.b[0] = disk;
--
1.7.2.5

On Tue, 17 Sep, at 04:42:24PM, Raphael S.Carvalho wrote:
> eparam would only be used if EBIOS is available.
> If it is not, then there is no reason to allocate eparam.
> 
> Signed-off-by: Raphael S.Carvalho <raphael.scarv at gmail.com>
> ---
>  com32/lib/syslinux/disk.c |   10 +++++-----
>  1 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/com32/lib/syslinux/disk.c b/com32/lib/syslinux/disk.c
> index 093751a..d96acbf 100644
> --- a/com32/lib/syslinux/disk.c
> +++ b/com32/lib/syslinux/disk.c
> @@ -73,7 +73,7 @@ int disk_int13_retry(const com32sys_t * inreg, com32sys_t
* outreg)
>  int disk_get_params(int disk, struct disk_info *const diskinfo)
>  {
>      static com32sys_t inreg, outreg;
> -    struct disk_ebios_eparam *eparam;
> +    struct disk_ebios_eparam *eparam = NULL;
>      int rv = 0;
> 
>      memset(diskinfo, 0, sizeof *diskinfo);
> @@ -94,12 +94,12 @@ int disk_get_params(int disk, struct disk_info *const
diskinfo)
>  	diskinfo->ebios = 1;
>      }
> 
> -    eparam = lmalloc(sizeof *eparam);
> -    if (!eparam)
> -	return -1;
> -
>      /* Get extended disk parameters if ebios == 1 */
>      if (diskinfo->ebios) {
> +	eparam = lmalloc(sizeof *eparam);
> +	if (!eparam)
> +	    return -1;
> +
>  	memset(&inreg, 0, sizeof inreg);
>  	inreg.eax.b[1] = 0x48;
>  	inreg.edx.b[0] = disk;
It would be better to move the lfree(), and in fact the declaration of
'eparam' under...

    if (diskbios->ebios) {
	struct disk_ebios_eparam *eparam;

	eparam = lmalloc();

	...

	lfree(eparam);
    }

since it's not used anywhere else. Make sense?

-- 
Matt Fleming, Intel Open Source Technology Center

>
> It would be better to move the lfree(), and in fact the declaration of
> 'eparam' under...
>
>     if (diskbios->ebios) {
>         struct disk_ebios_eparam *eparam;
>
>         eparam = lmalloc();
>
>         ...
>
>         lfree(eparam);
>     }
>
> since it's not used anywhere else. Make sense?
>
> --
> Matt Fleming, Intel Open Source Technology Center
Agreed. I will resend it with this change.
I initially thought it would be later used by inreg on __intcall, but
inreg is cleaned before __intcall is used again.

Regards,
Raphael S. Carvalho.