Re: [PATCH 1/2] take the segment adding out of locate_mem_hole functions

From: Vivek Goyal
Date: Tue Aug 12 2014 - 17:00:54 EST


On Tue, Aug 12, 2014 at 01:29:27PM +0800, Baoquan He wrote:
> In locate_mem_hole functions, a memory hole is located and added as
> kexec_segment. But from the name of locate_mem_hole, it should only
> take responsibility of searching a available memory hole to contain
> data of a specified size.
>
> So in this patch add a new field 'mem' into kexec_buf, then take that
> kexec segment adding code out of locate_mem_hole_top_down and
> locate_mem_hole_bottom_up. This make clear of the functionality of
> locate_mem_hole just like it declars to do. And by this
> locate_mem_hole_callback chould be used later if anyone want to locate
> a memory hole for other use.
>
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> ---
> include/linux/kexec.h | 1 +
> kernel/kexec.c | 9 +++++----
> 2 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 4b2a0e1..9d957b7 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -178,6 +178,7 @@ struct kexec_buf {
> struct kimage *image;
> char *buffer;
> unsigned long bufsz;
> + unsigned long mem;
> unsigned long memsz;
> unsigned long buf_align;
> unsigned long buf_min;
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index 0b49a0a..586444e 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -2054,8 +2054,7 @@ static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
> } while (1);
>
> /* If we are here, we found a suitable memory range */
> - __kexec_add_segment(image, kbuf->buffer, kbuf->bufsz, temp_start, > - kbuf->memsz);
> + kbuf->mem = temp_start;
>
> /* Success, stop navigating through remaining System RAM ranges */
> return 1;
> @@ -2089,8 +2088,7 @@ static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
> } while (1);
>
> /* If we are here, we found a suitable memory range */
> - __kexec_add_segment(image, kbuf->buffer, kbuf->bufsz, temp_start,
> - kbuf->memsz);
> + kbuf->mem = temp_start;
>
> /* Success, stop navigating through remaining System RAM ranges */
> return 1;
> @@ -2176,6 +2174,9 @@ int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz,
> return -EADDRNOTAVAIL;
> }
>
> + __kexec_add_segment(image, kbuf->buffer, kbuf->bufsz, kbuf->mem,
> + kbuf->memsz);
> +

I think let us open code this function then. That way we have to
retreive ksegment pointer once and it is easy to read.

/* Found a suitable memory range */
ksegment = &image->segment[image->nr_segments];
ksegment->kbuf = kbuf->buffer;
ksegment->bufsz = kbuf->bufsz;
ksegment->mem = kbuf->mem;
ksegment->memsz = kbuf->memsz;
image->nr_segments++;
*load_addr = ksegment->mem;

> /* Found a suitable memory range */
> ksegment = &image->segment[image->nr_segments - 1];
> *load_addr = ksegment->mem;

If possible, can you hold on to your cleanup patches for a bit. I want
to post some patches to introduce a config option for new syscall and
they will need to go in sooner. You can rebase your patches on top of
that.

Thanks
Vivek
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