[PATCH 1/2] kexec: add a helper function to add ranges

[Mahesh Jagannath Salgaonkar]

On 02/20/2018 07:48 PM, Hari Bathini wrote:
> Add a helper function for adding ranges to avoid duplicating code.
> 
> Signed-off-by: Hari Bathini <hbathini at linux.vnet.ibm.com>

Reviewed-by: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>

> ---
>  kexec/fs2dt.c |  115 ++++++++++++++++++++++++++-------------------------------
>  1 file changed, 53 insertions(+), 62 deletions(-)
> 
> diff --git a/kexec/fs2dt.c b/kexec/fs2dt.c
> index 79aa0f3..550eca9 100644
> --- a/kexec/fs2dt.c
> +++ b/kexec/fs2dt.c
> @@ -169,6 +169,50 @@ static unsigned propnum(const char *name)
>  	return offset;
>  }
> 
> +/*
> + * Add ranges by comparing 'base' and 'end' addresses with usable
> + * memory ranges. Returns the number of ranges added. Each range added
> + * increments 'idx' by 2.
> + */
> +static uint64_t add_ranges(uint64_t **ranges, int *ranges_size, int idx,
> +			   uint64_t base, uint64_t end)
> +{
> +	uint64_t loc_base, loc_end, rngs_cnt = 0;
> +	size_t range;
> +	int add = 0;
> +
> +	for (range = 0; range < usablemem_rgns.size; range++) {
> +		loc_base = usablemem_rgns.ranges[range].start;
> +		loc_end = usablemem_rgns.ranges[range].end;
> +		if (loc_base >= base && loc_end <= end) {
> +			add = 1;
> +		} else if (base < loc_end && end > loc_base) {
> +			if (loc_base < base)
> +				loc_base = base;
> +			if (loc_end > end)
> +				loc_end = end;
> +			add = 1;
> +		}
> +
> +		if (add) {
> +			if (idx >= ((*ranges_size) - 2)) {
> +				(*ranges_size) += MEM_RANGE_CHUNK_SZ;
> +				*ranges = realloc(*ranges, (*ranges_size)*8);
> +				if (!(*ranges))
> +					die("unrecoverable error: can't realloc"
> +					    "%d bytes for ranges.\n",
> +					    (*ranges_size)*8);
> +			}
> +			(*ranges)[idx++] = cpu_to_be64(loc_base);
> +			(*ranges)[idx++] = cpu_to_be64(loc_end - loc_base);
> +
> +			rngs_cnt++;
> +		}
> +	}
> +
> +	return rngs_cnt;
> +}
> +
>  #ifdef HAVE_DYNAMIC_MEMORY
>  static void add_dyn_reconf_usable_mem_property__(int fd)
>  {
> @@ -176,8 +220,8 @@ static void add_dyn_reconf_usable_mem_property__(int fd)
>  	uint64_t buf[32];
>  	uint64_t *ranges;
>  	int ranges_size = MEM_RANGE_CHUNK_SZ;
> -	uint64_t base, end, loc_base, loc_end;
> -	size_t i, rngs_cnt, range;
> +	uint64_t base, end, rngs_cnt;
> +	size_t i;
>  	int rlen = 0;
>  	int tmp_indx;
> 
> @@ -210,36 +254,8 @@ static void add_dyn_reconf_usable_mem_property__(int fd)
> 
>  		tmp_indx = rlen++;
> 
> -		rngs_cnt = 0;
> -		for (range = 0; range < usablemem_rgns.size; range++) {
> -			int add = 0;
> -			loc_base = usablemem_rgns.ranges[range].start;
> -			loc_end = usablemem_rgns.ranges[range].end;
> -			if (loc_base >= base && loc_end <= end) {
> -				add = 1;
> -			} else if (base < loc_end && end > loc_base) {
> -				if (loc_base < base)
> -					loc_base = base;
> -				if (loc_end > end)
> -					loc_end = end;
> -				add = 1;
> -			}
> -
> -			if (add) {
> -				if (rlen >= (ranges_size-2)) {
> -					ranges_size += MEM_RANGE_CHUNK_SZ;
> -					ranges = realloc(ranges, ranges_size*8);
> -					if (!ranges)
> -						die("unrecoverable error: can't"
> -						    " realloc %d bytes for"
> -						    " ranges.\n",
> -						    ranges_size*8);
> -				}
> -				ranges[rlen++] = cpu_to_be64(loc_base);
> -				ranges[rlen++] = cpu_to_be64(loc_end - loc_base);
> -				rngs_cnt++;
> -			}
> -		}
> +		rngs_cnt = add_ranges(&ranges, &ranges_size, rlen,
> +				      base, end);
>  		if (rngs_cnt == 0) {
>  			/* We still need to add a counter for every LMB because
>  			 * the kernel parsing code is dumb.  We just have
> @@ -261,7 +277,8 @@ static void add_dyn_reconf_usable_mem_property__(int fd)
>  			}
>  		} else {
>  			/* Store the count of (base, size) duple */
> -			ranges[tmp_indx] = cpu_to_be64((uint64_t) rngs_cnt);
> +			ranges[tmp_indx] = cpu_to_be64(rngs_cnt);
> +			rlen += rngs_cnt * 2;
>  		}
>  	}
>  		
> @@ -294,8 +311,7 @@ static void add_usable_mem_property(int fd, size_t len)
>  	uint64_t buf[2];
>  	uint64_t *ranges;
>  	int ranges_size = MEM_RANGE_CHUNK_SZ;
> -	uint64_t base, end, loc_base, loc_end;
> -	size_t range;
> +	uint64_t base, end, rngs_cnt;
>  	int rlen = 0;
> 
>  	strcpy(fname, pathname);
> @@ -326,33 +342,8 @@ static void add_usable_mem_property(int fd, size_t len)
>  		die("unrecoverable error: can't alloc %zu bytes for ranges.\n",
>  		    ranges_size * sizeof(*ranges));
> 
> -	for (range = 0; range < usablemem_rgns.size; range++) {
> -		int add = 0;
> -		loc_base = usablemem_rgns.ranges[range].start;
> -		loc_end = usablemem_rgns.ranges[range].end;
> -		if (loc_base >= base && loc_end <= end) {
> -			add = 1;
> -		} else if (base < loc_end && end > loc_base) {
> -			if (loc_base < base)
> -				loc_base = base;
> -			if (loc_end > end)
> -				loc_end = end;
> -			add = 1;
> -		}
> -		if (add) {
> -			if (rlen >= (ranges_size-2)) {
> -				ranges_size += MEM_RANGE_CHUNK_SZ;
> -				ranges = realloc(ranges, ranges_size *
> -						 sizeof(*ranges));
> -				if (!ranges)
> -					die("unrecoverable error: can't realloc"
> -					    "%zu bytes for ranges.\n",
> -					    ranges_size*sizeof(*ranges));
> -			}
> -			ranges[rlen++] = cpu_to_be64(loc_base);
> -			ranges[rlen++] = cpu_to_be64(loc_end - loc_base);
> -		}
> -	}
> +	rngs_cnt = add_ranges(&ranges, &ranges_size, rlen, base, end);
> +	rlen += rngs_cnt * 2;
> 
>  	if (!rlen) {
>  		/*
>