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From: Simon Horman on 13 Aug 2010 04:00
On Fri, Aug 13, 2010 at 01:38:54AM -0400, Amerigo Wang wrote:
>
> Currently KEXEC_SEGMENT_MAX is only 16 which is too small for machine with
> many memory ranges. When hibernate on a machine with disjoint memory we do
> need one segment for each memory region. Increase this hard limit to 16K
> which is reasonably large.
>
> And change ->segment from a static array to a dynamically allocated memory.

FWIW, this looks good to me.

Reviewed-by: Simon Horman <horms(a)verge.net.au>

>
> Cc: Neil Horman <nhorman(a)redhat.com>
> Cc: Vivek Goyal <vgoyal(a)redhat.com>
> Cc: huang ying <huang.ying.caritas(a)gmail.com>
> Cc: Eric W. Biederman <ebiederm(a)xmission.com>
> Cc: Benjamin Herrenschmidt <benh(a)kernel.crashing.org>
> Cc: Paul Mackerras <paulus(a)samba.org>
> Signed-off-by: WANG Cong <amwang(a)redhat.com>
>
> ---
>
> diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
> index 583af70..93f0542 100644
> --- a/arch/powerpc/kernel/machine_kexec_64.c
> +++ b/arch/powerpc/kernel/machine_kexec_64.c
> @@ -134,10 +134,7 @@ static void copy_segments(unsigned long ind)
> void kexec_copy_flush(struct kimage *image)
> {
> long i, nr_segments = image->nr_segments;
> - struct kexec_segment ranges[KEXEC_SEGMENT_MAX];
> -
> - /* save the ranges on the stack to efficiently flush the icache */
> - memcpy(ranges, image->segment, sizeof(ranges));
> + struct kexec_segment range;
>
> /*
> * After this call we may not use anything allocated in dynamic
> @@ -151,9 +148,11 @@ void kexec_copy_flush(struct kimage *image)
> * we need to clear the icache for all dest pages sometime,
> * including ones that were in place on the original copy
> */
> - for (i = 0; i < nr_segments; i++)
> - flush_icache_range((unsigned long)__va(ranges[i].mem),
> - (unsigned long)__va(ranges[i].mem + ranges[i].memsz));
> + for (i = 0; i < nr_segments; i++) {
> + memcpy(&range, &image->segment[i], sizeof(range));
> + flush_icache_range((unsigned long)__va(range.mem),
> + (unsigned long)__va(range.mem + range.memsz));
> + }
> }
>
> #ifdef CONFIG_SMP
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index 03e8e8d..ec783c1 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -57,7 +57,7 @@ typedef unsigned long kimage_entry_t;
> #define IND_DONE 0x4
> #define IND_SOURCE 0x8
>
> -#define KEXEC_SEGMENT_MAX 16
> +#define KEXEC_SEGMENT_MAX (1024*16)
> struct kexec_segment {
> void __user *buf;
> size_t bufsz;
> @@ -86,7 +86,7 @@ struct kimage {
> struct page *swap_page;
>
> unsigned long nr_segments;
> - struct kexec_segment segment[KEXEC_SEGMENT_MAX];
> + struct kexec_segment *segment;
>
> struct list_head control_pages;
> struct list_head dest_pages;
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index c0613f7..22ff794 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -131,6 +131,11 @@ static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
> if (!image)
> goto out;
>
> + image->segment = kzalloc(nr_segments * sizeof(struct kexec_segment),
> + GFP_KERNEL);
> + if (!image->segment)
> + goto out;
> +
> image->head = 0;
> image->entry = &image->head;
> image->last_entry = &image->head;
> @@ -218,8 +223,10 @@ static int do_kimage_alloc(struct kimage **rimage, unsigned long entry,
> out:
> if (result == 0)
> *rimage = image;
> - else
> + else if (image) {
> + kfree(image->segment);
> kfree(image);
> + }
>
> return result;
>
> @@ -263,8 +270,10 @@ static int kimage_normal_alloc(struct kimage **rimage, unsigned long entry,
> out:
> if (result == 0)
> *rimage = image;
> - else
> + else if (image) {
> + kfree(image->segment);
> kfree(image);
> + }
>
> return result;
> }
> @@ -332,8 +341,10 @@ static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry,
> out:
> if (result == 0)
> *rimage = image;
> - else
> + else if (image) {
> + kfree(image->segment);
> kfree(image);
> + }
>
> return result;
> }
> @@ -658,6 +669,7 @@ static void kimage_free(struct kimage *image)
>
> /* Free the kexec control pages... */
> kimage_free_page_list(&image->control_pages);
> + kfree(image->segment);
> kfree(image);
> }
>
> --
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