Re: [dm-devel] [PATCH v4 03/10] block: Introduce a new ioctl for copy

[Nitesh Shetty <nj.shetty@samsung.com>]

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O Wed, Apr 27, 2022 at 11:48:57AM +0900, Damien Le Moal wrote:
> On 4/26/22 19:12, Nitesh Shetty wrote:
> > Add new BLKCOPY ioctl that offloads copying of one or more sources ranges
> > to one or more destination in a device. COPY ioctl accepts a 'copy_range'
> > structure that contains no of range, a reserved field , followed by an
> > array of ranges. Each source range is represented by 'range_entry' that
> > contains source start offset, destination start offset and length of
> > source ranges (in bytes)
> > 
> > MAX_COPY_NR_RANGE, limits the number of entries for the IOCTL and
> > MAX_COPY_TOTAL_LENGTH limits the total copy length, IOCTL can handle.
> > 
> > Example code, to issue BLKCOPY:
> > /* Sample example to copy three entries with [dest,src,len],
> > * [32768, 0, 4096] [36864, 4096, 4096] [40960,8192,4096] on same device */
> > 
> > int main(void)
> > {
> > 	int i, ret, fd;
> > 	unsigned long src = 0, dst = 32768, len = 4096;
> > 	struct copy_range *cr;
> > 	cr = (struct copy_range *)malloc(sizeof(*cr)+
> > 					(sizeof(struct range_entry)*3));
> > 	cr->nr_range = 3;
> > 	cr->reserved = 0;
> > 	for (i = 0; i< cr->nr_range; i++, src += len, dst += len) {
> > 		cr->range_list[i].dst = dst;
> > 		cr->range_list[i].src = src;
> > 		cr->range_list[i].len = len;
> > 		cr->range_list[i].comp_len = 0;
> > 	}
> > 	fd = open("/dev/nvme0n1", O_RDWR);
> > 	if (fd < 0) return 1;
> > 	ret = ioctl(fd, BLKCOPY, cr);
> > 	if (ret != 0)
> > 	       printf("copy failed, ret= %d\n", ret);
> > 	for (i=0; i< cr->nr_range; i++)
> > 		if (cr->range_list[i].len != cr->range_list[i].comp_len)
> > 			printf("Partial copy for entry %d: requested %llu, completed %llu\n",
> > 								i, cr->range_list[i].len,
> > 								cr->range_list[i].comp_len);
> > 	close(fd);
> > 	free(cr);
> > 	return ret;
> > }
> 
> Nice to have a code example. But please format it correctly.
>

acked

--
Nitesh Shetty

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