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Commit 5cb2fbd6 authored by Shaohua Li's avatar Shaohua Li Committed by NeilBrown
Browse files

raid5-cache: use crc32c checksum 



crc32c has lower overhead with cpu acceleration. It's a shame I didn't
use it in first post, sorry. This changes disk format, but we are still
ok in current stage.

V2: delete unnecessary type conversion as pointed out by Bart

Signed-off-by: default avatarShaohua Li <shli@fb.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.com>
Reviewed-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
parent 355810d1

drivers/md/raid5-cache.c

+10 −10
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ 
#include <linux/blkdev.h>

#include <linux/slab.h>

#include <linux/raid/md_p.h>

#include <linux/crc32.h>

#include <linux/crc32c.h>

#include <linux/random.h>

#include "md.h"

#include "raid5.h"
@@ -282,7 +282,7 @@ static void r5l_submit_current_io(struct r5l_log *log) 


	block = page_address(io->meta_page);

	block->meta_size = cpu_to_le32(io->meta_offset);

	crc = crc32_le(log->uuid_checksum, (void *)block, PAGE_SIZE);

	crc = crc32c_le(log->uuid_checksum, block, PAGE_SIZE);

	block->checksum = cpu_to_le32(crc);



	log->current_io = NULL;
@@ -484,7 +484,7 @@ int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh) 
		if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))

			continue;

		addr = kmap_atomic(sh->dev[i].page);

		sh->dev[i].log_checksum = crc32_le(log->uuid_checksum,

		sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum,

						    addr, PAGE_SIZE);

		kunmap_atomic(addr);

	}
@@ -744,7 +744,7 @@ static int r5l_read_meta_block(struct r5l_log *log, 
	    le64_to_cpu(mb->position) != ctx->pos)

		return -EINVAL;



	crc = crc32_le(log->uuid_checksum, (void *)mb, PAGE_SIZE);

	crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);

	if (stored_crc != crc)

		return -EINVAL;
@@ -819,7 +819,7 @@ static int r5l_recovery_flush_one_stripe(struct r5l_log *log, 
		if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags))

			continue;

		addr = kmap_atomic(sh->dev[disk_index].page);

		checksum = crc32_le(log->uuid_checksum, addr, PAGE_SIZE);

		checksum = crc32c_le(log->uuid_checksum, addr, PAGE_SIZE);

		kunmap_atomic(addr);

		if (checksum != sh->dev[disk_index].log_checksum)

			goto error;
@@ -909,7 +909,7 @@ static int r5l_log_write_empty_meta_block(struct r5l_log *log, sector_t pos, 
	mb->meta_size = cpu_to_le32(sizeof(struct r5l_meta_block));

	mb->seq = cpu_to_le64(seq);

	mb->position = cpu_to_le64(pos);

	crc = crc32_le(log->uuid_checksum, (void *)mb, PAGE_SIZE);

	crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);

	mb->checksum = cpu_to_le32(crc);



	if (!sync_page_io(log->rdev, pos, PAGE_SIZE, page, WRITE_FUA, false)) {
@@ -1000,7 +1000,7 @@ static int r5l_load_log(struct r5l_log *log) 
	}

	stored_crc = le32_to_cpu(mb->checksum);

	mb->checksum = 0;

	expected_crc = crc32_le(log->uuid_checksum, (void *)mb, PAGE_SIZE);

	expected_crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);

	if (stored_crc != expected_crc) {

		create_super = true;

		goto create;
@@ -1047,7 +1047,7 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) 
		return -ENOMEM;

	log->rdev = rdev;



	log->uuid_checksum = crc32_le(~0, (void *)rdev->mddev->uuid,

	log->uuid_checksum = crc32c_le(~0, rdev->mddev->uuid,

				       sizeof(rdev->mddev->uuid));



	mutex_init(&log->io_mutex);