Re: [PATCH 05/13] x86/microcode/intel: Make _save_mc() return the updated saved count

Quentin Casasnovas
2015-02-24T16:21:10Z

On Tue, Feb 24, 2015 at 11:37:04AM +0100, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
>
> ... of microcode patches instead of handing in a pointer which is used
> for I/O in an otherwise void function.
>
> Signed-off-by: Borislav Petkov <bp@suse.de>
> ---
> arch/x86/kernel/cpu/microcode/intel_early.c | 29 ++++++++++++++---------------
> 1 file changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/microcode/intel_early.c b/arch/x86/kernel/cpu/microcode/intel_early.c
> index ffeac5d62eca..ee74e7726c33 100644
> --- a/arch/x86/kernel/cpu/microcode/intel_early.c
> +++ b/arch/x86/kernel/cpu/microcode/intel_early.c
> @@ -264,17 +264,18 @@ err:
> * - or if it is a newly discovered microcode patch.
> *
> * The microcode patch should have matching model with CPU.
> + *
> + * Returns: The updated number @num_saved of saved microcode patches.
> */
> -static void _save_mc(struct microcode_intel **mc_saved, u8 *ucode_ptr,
> - unsigned int *mc_saved_count_p)
> +static unsigned int _save_mc(struct microcode_intel **mc_saved,
> + u8 *ucode_ptr, unsigned int num_saved)
> {
> - int i;
> - int found = 0;
> - unsigned int mc_saved_count = *mc_saved_count_p;
> struct microcode_header_intel *mc_header;
> + int found = 0, i;
>
> mc_header = (struct microcode_header_intel *)ucode_ptr;
> - for (i = 0; i < mc_saved_count; i++) {
> +
> + for (i = 0; i < num_saved; i++) {

Minor comment: since num_saved is unsigned, I think it would be better to
just use an unsigned int for `i` as well.

> unsigned int sig, pf;
> unsigned int new_rev;
> struct microcode_header_intel *mc_saved_header =
> @@ -291,21 +292,20 @@ static void _save_mc(struct microcode_intel **mc_saved, u8 *ucode_ptr,
> * Replace the older one with this newer
> * one.
> */
> - mc_saved[i] =
> - (struct microcode_intel *)ucode_ptr;
> + mc_saved[i] = (struct microcode_intel *)ucode_ptr;
> break;
> }
> }
> }
> - if (i >= mc_saved_count && !found)
> +
> + if (i >= num_saved && !found)

While at it, I could not find that `i` would ever be bigger than
`num_saved` so maybe you can just test for equality instead? It just makes
it clearer what the code does.

Quentin