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: Shaohua Li <shli@fb.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>

drivers/md/raid5-cache.c

@@ -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;
@@ -484,8 +484,8 @@ 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,
-						   addr, PAGE_SIZE);
+		sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum,
+						    addr, PAGE_SIZE);
 		kunmap_atomic(addr);
 	}
 	parity_pages = 1 + !!(sh->qd_idx >= 0);
@@ -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;
@@ -1047,8 +1047,8 @@ 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,
-				      sizeof(rdev->mddev->uuid));
+	log->uuid_checksum = crc32c_le(~0, rdev->mddev->uuid,
+				       sizeof(rdev->mddev->uuid));
 
 	mutex_init(&log->io_mutex);