Re: [PATCH v5 02/31] powerpc/fadump: move internal code to a new file

[Michael Ellerman <mpe@ellerman.id.au>]

Hari Bathini <hbathini@linux.ibm.com> writes:
> Make way for refactoring platform specific FADump code by moving code
> that could be referenced from multiple places to fadump-common.c file.
>
> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
> ---
>  arch/powerpc/kernel/Makefile        |    2 
>  arch/powerpc/kernel/fadump-common.c |  140 ++++++++++++++++++++++++++++++++++
>  arch/powerpc/kernel/fadump-common.h |    8 ++
>  arch/powerpc/kernel/fadump.c        |  146 ++---------------------------------
>  4 files changed, 158 insertions(+), 138 deletions(-)
>  create mode 100644 arch/powerpc/kernel/fadump-common.c

I don't understand why we need fadump.c and fadump-common.c? They're
both common/shared across pseries & powernv aren't they?

By the end of the series we end up with 149 lines in fadump-common.c
which seems like a waste of time. Just put it all in fadump.c.

> diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
> index 56dfa7a..439d548 100644
> --- a/arch/powerpc/kernel/Makefile
> +++ b/arch/powerpc/kernel/Makefile
> @@ -78,7 +78,7 @@ obj-$(CONFIG_EEH)              += eeh.o eeh_pe.o eeh_dev.o eeh_cache.o \
>  				  eeh_driver.o eeh_event.o eeh_sysfs.o
>  obj-$(CONFIG_GENERIC_TBSYNC)	+= smp-tbsync.o
>  obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
> -obj-$(CONFIG_FA_DUMP)		+= fadump.o
> +obj-$(CONFIG_FA_DUMP)		+= fadump.o fadump-common.o
>  ifdef CONFIG_PPC32
>  obj-$(CONFIG_E500)		+= idle_e500.o
>  endif
> diff --git a/arch/powerpc/kernel/fadump-common.c b/arch/powerpc/kernel/fadump-common.c
> new file mode 100644
> index 0000000..7f39e4f
> --- /dev/null
> +++ b/arch/powerpc/kernel/fadump-common.c
> @@ -0,0 +1,140 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Firmware-Assisted Dump internal code.
> + *
> + * Copyright 2011, IBM Corporation
> + * Author: Mahesh Salgaonkar <mahesh@linux.ibm.com>

Can we not put emails in C files anymore please, they just bitrot, just
the names is fine.

> + * Copyright 2019, IBM Corp.
> + * Author: Hari Bathini <hbathini@linux.ibm.com>

These can just be:

 * Copyright 2011, Mahesh Salgaonkar, IBM Corporation.
 * Copyright 2019, Hari Bathini, IBM Corporation.

> + */
> +
> +#undef DEBUG

Don't undef DEBUG please.

> +#define pr_fmt(fmt) "fadump: " fmt
> +
> +#include <linux/memblock.h>
> +#include <linux/elf.h>
> +#include <linux/mm.h>
> +#include <linux/crash_core.h>
> +
> +#include "fadump-common.h"
> +
> +void *fadump_cpu_notes_buf_alloc(unsigned long size)
> +{
> +	void *vaddr;
> +	struct page *page;
> +	unsigned long order, count, i;
> +
> +	order = get_order(size);
> +	vaddr = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
> +	if (!vaddr)
> +		return NULL;
> +
> +	count = 1 << order;
> +	page = virt_to_page(vaddr);
> +	for (i = 0; i < count; i++)
> +		SetPageReserved(page + i);
> +	return vaddr;
> +}

I realise you're just moving this code, but why do we need all this hand
rolled allocation stuff?

cheers