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Date:   Fri, 27 Jul 2018 14:25:14 +0900
From:   AKASHI Takahiro <takahiro.akashi@linaro.org>
To:     Dave Young <dyoung@redhat.com>
Cc:     catalin.marinas@arm.com, will.deacon@arm.com, dhowells@redhat.com,
        vgoyal@redhat.com, herbert@gondor.apana.org.au,
        davem@davemloft.net, bhe@redhat.com, arnd@arndb.de,
        schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com,
        ard.biesheuvel@linaro.org, james.morse@arm.com,
        bhsharma@redhat.com, kexec@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        "Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH v12 04/16] powerpc, kexec_file: factor out memblock-based
 arch_kexec_walk_mem()
Message-ID: <20180727052513.GE11258@linaro.org>
Mail-Followup-To: AKASHI Takahiro <takahiro.akashi@linaro.org>,
        Dave Young <dyoung@redhat.com>, catalin.marinas@arm.com,
        will.deacon@arm.com, dhowells@redhat.com, vgoyal@redhat.com,
        herbert@gondor.apana.org.au, davem@davemloft.net, bhe@redhat.com,
        arnd@arndb.de, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com,
        ard.biesheuvel@linaro.org, james.morse@arm.com, bhsharma@redhat.com,
        kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org,
        "Eric W. Biederman" <ebiederm@xmission.com>
References: <20180724065759.19186-1-takahiro.akashi@linaro.org>
 <20180724065759.19186-5-takahiro.akashi@linaro.org>
 <20180725123129.GA2361@dhcp-128-65.nay.redhat.com>
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On Wed, Jul 25, 2018 at 08:31:29PM +0800, Dave Young wrote:
> On 07/24/18 at 03:57pm, AKASHI Takahiro wrote:
> > Memblock list is another source for usable system memory layout.
> > So move powerpc's arch_kexec_walk_mem() to common code so that other
> > memblock-based architectures, particularly arm64, can also utilise it.
> > A moved function is now renamed to kexec_walk_memblock() and integrated
> > into kexec_locate_mem_hole(), which will now be usable for all
> > architectures with no need for overriding arch_kexec_walk_mem().
> > 
> > kexec_walk_memblock() will not work for kdump in this form, this will be
> > fixed in the next patch.
> > 
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> > Cc: Dave Young <dyoung@redhat.com>
> > Cc: Vivek Goyal <vgoyal@redhat.com>
> > Cc: Baoquan He <bhe@redhat.com>
> > Acked-by: James Morse <james.morse@arm.com>
> > ---
> >  arch/powerpc/kernel/machine_kexec_file_64.c | 54 -------------------
> >  include/linux/kexec.h                       |  2 -
> >  kernel/kexec_file.c                         | 58 ++++++++++++++++++++-
> >  3 files changed, 56 insertions(+), 58 deletions(-)
> > 
> > diff --git a/arch/powerpc/kernel/machine_kexec_file_64.c b/arch/powerpc/kernel/machine_kexec_file_64.c
> > index 0bd23dc789a4..5357b09902c5 100644
> > --- a/arch/powerpc/kernel/machine_kexec_file_64.c
> > +++ b/arch/powerpc/kernel/machine_kexec_file_64.c
> > @@ -24,7 +24,6 @@
> >  
> >  #include <linux/slab.h>
> >  #include <linux/kexec.h>
> > -#include <linux/memblock.h>
> >  #include <linux/of_fdt.h>
> >  #include <linux/libfdt.h>
> >  #include <asm/ima.h>
> > @@ -46,59 +45,6 @@ int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
> >  	return kexec_image_probe_default(image, buf, buf_len);
> >  }
> >  
> > -/**
> > - * arch_kexec_walk_mem - call func(data) for each unreserved memory block
> > - * @kbuf:	Context info for the search. Also passed to @func.
> > - * @func:	Function to call for each memory block.
> > - *
> > - * This function is used by kexec_add_buffer and kexec_locate_mem_hole
> > - * to find unreserved memory to load kexec segments into.
> > - *
> > - * Return: The memory walk will stop when func returns a non-zero value
> > - * and that value will be returned. If all free regions are visited without
> > - * func returning non-zero, then zero will be returned.
> > - */
> > -int arch_kexec_walk_mem(struct kexec_buf *kbuf,
> > -			int (*func)(struct resource *, void *))
> > -{
> > -	int ret = 0;
> > -	u64 i;
> > -	phys_addr_t mstart, mend;
> > -	struct resource res = { };
> > -
> > -	if (kbuf->top_down) {
> > -		for_each_free_mem_range_reverse(i, NUMA_NO_NODE, 0,
> > -						&mstart, &mend, NULL) {
> > -			/*
> > -			 * In memblock, end points to the first byte after the
> > -			 * range while in kexec, end points to the last byte
> > -			 * in the range.
> > -			 */
> > -			res.start = mstart;
> > -			res.end = mend - 1;
> > -			ret = func(&res, kbuf);
> > -			if (ret)
> > -				break;
> > -		}
> > -	} else {
> > -		for_each_free_mem_range(i, NUMA_NO_NODE, 0, &mstart, &mend,
> > -					NULL) {
> > -			/*
> > -			 * In memblock, end points to the first byte after the
> > -			 * range while in kexec, end points to the last byte
> > -			 * in the range.
> > -			 */
> > -			res.start = mstart;
> > -			res.end = mend - 1;
> > -			ret = func(&res, kbuf);
> > -			if (ret)
> > -				break;
> > -		}
> > -	}
> > -
> > -	return ret;
> > -}
> > -
> >  /**
> >   * setup_purgatory - initialize the purgatory's global variables
> >   * @image:		kexec image.
> > diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> > index 49ab758f4d91..c196bfd11bee 100644
> > --- a/include/linux/kexec.h
> > +++ b/include/linux/kexec.h
> > @@ -184,8 +184,6 @@ int __weak arch_kexec_apply_relocations(struct purgatory_info *pi,
> >  					const Elf_Shdr *relsec,
> >  					const Elf_Shdr *symtab);
> >  
> > -int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
> > -			       int (*func)(struct resource *, void *));
> >  extern int kexec_add_buffer(struct kexec_buf *kbuf);
> >  int kexec_locate_mem_hole(struct kexec_buf *kbuf);
> >  
> > diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
> > index bf39df5e5bb9..2f0691b0f8ad 100644
> > --- a/kernel/kexec_file.c
> > +++ b/kernel/kexec_file.c
> > @@ -16,6 +16,7 @@
> >  #include <linux/file.h>
> >  #include <linux/slab.h>
> >  #include <linux/kexec.h>
> > +#include <linux/memblock.h>
> >  #include <linux/mutex.h>
> >  #include <linux/list.h>
> >  #include <linux/fs.h>
> > @@ -501,6 +502,55 @@ static int locate_mem_hole_callback(struct resource *res, void *arg)
> >  	return locate_mem_hole_bottom_up(start, end, kbuf);
> >  }
> >  
> > +#if defined(CONFIG_HAVE_MEMBLOCK) && !defined(CONFIG_ARCH_DISCARD_MEMBLOCK)
> > +static int kexec_walk_memblock(struct kexec_buf *kbuf,
> > +			       int (*func)(struct resource *, void *))
> > +{
> > +	int ret = 0;
> > +	u64 i;
> > +	phys_addr_t mstart, mend;
> > +	struct resource res = { };
> > +
> > +	if (kbuf->top_down) {
> > +		for_each_free_mem_range_reverse(i, NUMA_NO_NODE, 0,
> > +						&mstart, &mend, NULL) {
> > +			/*
> > +			 * In memblock, end points to the first byte after the
> > +			 * range while in kexec, end points to the last byte
> > +			 * in the range.
> > +			 */
> > +			res.start = mstart;
> > +			res.end = mend - 1;
> > +			ret = func(&res, kbuf);
> > +			if (ret)
> > +				break;
> > +		}
> > +	} else {
> > +		for_each_free_mem_range(i, NUMA_NO_NODE, 0, &mstart, &mend,
> > +					NULL) {
> > +			/*
> > +			 * In memblock, end points to the first byte after the
> > +			 * range while in kexec, end points to the last byte
> > +			 * in the range.
> > +			 */
> > +			res.start = mstart;
> > +			res.end = mend - 1;
> > +			ret = func(&res, kbuf);
> > +			if (ret)
> > +				break;
> > +		}
> > +	}
> > +
> > +	return ret;
> > +}
> > +#else
> > +static int kexec_walk_memblock(struct kexec_buf *kbuf,
> > +			       int (*func)(struct resource *, void *))
> > +{
> > +	return 0;
> > +}
> > +#endif
> > +
> >  /**
> >   * arch_kexec_walk_mem - call func(data) on free memory regions
> >   * @kbuf:	Context info for the search. Also passed to @func.
> > @@ -510,7 +560,7 @@ static int locate_mem_hole_callback(struct resource *res, void *arg)
> >   * and that value will be returned. If all free regions are visited without
> >   * func returning non-zero, then zero will be returned.
> >   */
> > -int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
> > +static int arch_kexec_walk_mem(struct kexec_buf *kbuf,
> >  			       int (*func)(struct resource *, void *))
> >  {
> >  	if (kbuf->image->type == KEXEC_TYPE_CRASH)
> > @@ -538,7 +588,11 @@ int kexec_locate_mem_hole(struct kexec_buf *kbuf)
> >  	if (kbuf->mem)
> >  		return 0;
> >  
> > -	ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback);
> > +	if (IS_ENABLED(CONFIG_HAVE_MEMBLOCK) &&
> > +			!IS_ENABLED(CONFIG_ARCH_DISCARD_MEMBLOCK))
> > +		ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback);
> > +	else
> > +		ret = arch_kexec_walk_mem(kbuf, locate_mem_hole_callback);
> 
> AKASHI, since it is not weak function now, it would be better to rename
> the function for example name it as kexec_walk_resource()

OK.

-Takahiro AKASHI


> Other than this,
> 
> Acked-by: Dave Young <dyoung@redhat.com>
> 
> >  
> >  	return ret == 1 ? 0 : -EADDRNOTAVAIL;
> >  }
> > -- 
> > 2.18.0
> > 
> 
> Thanks
> Dave