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SubjectRe: [PATCH][v6] PM / hibernate: Print the possible panic reason when resuming with inconsistent e820 map
Hi!

> > > > What's the progress of this patch? Looks already have experts review it.
> > > > Why this patch didn't accept?
> > > This patch is a little overkilled, and I have saved another simpler
> > > version to only check the md5 hash (as people suggested) for it. I can post it later.
> > >
> >
> > I am happy to test and review it.
> >
> Here it is. As Rafael is on travel, it would be grateful
> if you can give some advance on this, thanks!

Better than last one.

> +#ifdef CONFIG_HIBERNATION_CHECK_E820
> +#define MD5_HASH_SIZE 128
> +
> +/**
> + * get_e820_md5 - calculate md5 according to struct e820map
> + *
> + * @map: the e820 map to be calculated
> + * @buf: the md5 result to be stored to
> + */
> +static int get_e820_md5(struct e820map *map, void *buf)
> +{
> + struct scatterlist sg;
> + struct crypto_ahash *tfm;
> + struct ahash_request *req;
> + int ret = 0;
> +
> + tfm = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
> + if (IS_ERR(tfm))
> + return -ENOMEM;
> +
> + req = ahash_request_alloc(tfm, GFP_ATOMIC);

what context is this called from? GFP_ATOMIC allocations like to fail...

> +static int hibernation_e820_check(void *buf)
> +{
> + int ret;
> + char result[MD5_HASH_SIZE] = {0};
> +
> + ret = get_e820_md5(&e820_saved, result);
> + if (ret)
> + return ret;
> +
> + if (memcmp(result, buf, MD5_HASH_SIZE))
> + e820_conflict = true;

Passing return value using global variable is ugly. Can you just print
the warning and kill the box here?
> +

> + /*
> + * A page has been allocated previously to store the hibernation
> + * image header, so we can safely store the md5 result behind
> + * struct restore_data_record, with size of 128 bytes.
> + */
> + hibernation_e820_save(addr + sizeof(struct restore_data_record));
> +

Please just allocate space in struct restore_data_record . And I don't
think md5 sum is 128 _bytes_.

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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