dm vdo: clean up scnprintf usage

Ignore scnprintf return status since it is not necessary. Change
write_* functions type from int to void since we no longer return
any result. Also, clean up any code that checks or uses any scnprintf
return results.
Check uds_allocate return code which was previous ignored, return
and log error when uds_allocate failed.
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Chung Chung <cchung@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

drivers/md/dm-vdo/message-stats.c

@@ -11,749 +11,407 @@
 #include "thread-device.h"
 #include "vdo.h"
 
-static int write_u64(char *prefix, u64 value, char *suffix, char **buf,
-		     unsigned int *maxlen)
+static void write_u64(char *prefix, u64 value, char *suffix, char **buf,
+		      unsigned int *maxlen)
 {
-	int count = scnprintf(*buf, *maxlen, "%s%llu%s", prefix == NULL ? "" : prefix,
-			      value, suffix == NULL ? "" : suffix);
+	int count;
+
+	count = scnprintf(*buf, *maxlen, "%s%llu%s", prefix == NULL ? "" : prefix,
+			  value, suffix == NULL ? "" : suffix);
 	*buf += count;
 	*maxlen -= count;
-	if (count >= *maxlen)
-		return VDO_UNEXPECTED_EOF;
-	return VDO_SUCCESS;
 }
 
-static int write_u32(char *prefix, u32 value, char *suffix, char **buf,
-		     unsigned int *maxlen)
+static void write_u32(char *prefix, u32 value, char *suffix, char **buf,
+		      unsigned int *maxlen)
 {
-	int count = scnprintf(*buf, *maxlen, "%s%u%s", prefix == NULL ? "" : prefix,
-			      value, suffix == NULL ? "" : suffix);
+	int count;
+
+	count = scnprintf(*buf, *maxlen, "%s%u%s", prefix == NULL ? "" : prefix,
+			  value, suffix == NULL ? "" : suffix);
 	*buf += count;
 	*maxlen -= count;
-	if (count >= *maxlen)
-		return VDO_UNEXPECTED_EOF;
-	return VDO_SUCCESS;
 }
 
-static int write_block_count_t(char *prefix, block_count_t value, char *suffix,
-			       char **buf, unsigned int *maxlen)
+static void write_block_count_t(char *prefix, block_count_t value, char *suffix,
+				char **buf, unsigned int *maxlen)
 {
-	int count = scnprintf(*buf, *maxlen, "%s%llu%s", prefix == NULL ? "" : prefix,
-			      value, suffix == NULL ? "" : suffix);
+	int count;
+
+	count = scnprintf(*buf, *maxlen, "%s%llu%s", prefix == NULL ? "" : prefix,
+			  value, suffix == NULL ? "" : suffix);
 	*buf += count;
 	*maxlen -= count;
-	if (count >= *maxlen)
-		return VDO_UNEXPECTED_EOF;
-	return VDO_SUCCESS;
 }
 
-static int write_string(char *prefix, char *value, char *suffix, char **buf,
-			unsigned int *maxlen)
+static void write_string(char *prefix, char *value, char *suffix, char **buf,
+			 unsigned int *maxlen)
 {
-	int count = scnprintf(*buf, *maxlen, "%s%s%s", prefix == NULL ? "" : prefix,
-			      value, suffix == NULL ? "" : suffix);
+	int count;
+
+	count = scnprintf(*buf, *maxlen, "%s%s%s", prefix == NULL ? "" : prefix,
+			  value, suffix == NULL ? "" : suffix);
 	*buf += count;
 	*maxlen -= count;
-	if (count >= *maxlen)
-		return VDO_UNEXPECTED_EOF;
-	return VDO_SUCCESS;
 }
 
-static int write_bool(char *prefix, bool value, char *suffix, char **buf,
-		      unsigned int *maxlen)
+static void write_bool(char *prefix, bool value, char *suffix, char **buf,
+		       unsigned int *maxlen)
 {
-	int count = scnprintf(*buf, *maxlen, "%s%d%s", prefix == NULL ? "" : prefix,
-			      value, suffix == NULL ? "" : suffix);
+	int count;
+
+	count = scnprintf(*buf, *maxlen, "%s%d%s", prefix == NULL ? "" : prefix,
+			  value, suffix == NULL ? "" : suffix);
 	*buf += count;
 	*maxlen -= count;
-	if (count >= *maxlen)
-		return VDO_UNEXPECTED_EOF;
-	return VDO_SUCCESS;
 }
 
-static int write_u8(char *prefix, u8 value, char *suffix, char **buf,
-		    unsigned int *maxlen)
+static void write_u8(char *prefix, u8 value, char *suffix, char **buf,
+		     unsigned int *maxlen)
 {
-	int count = scnprintf(*buf, *maxlen, "%s%u%s", prefix == NULL ? "" : prefix,
-			      value, suffix == NULL ? "" : suffix);
+	int count;
+
+	count = scnprintf(*buf, *maxlen, "%s%u%s", prefix == NULL ? "" : prefix,
+			  value, suffix == NULL ? "" : suffix);
 	*buf += count;
 	*maxlen -= count;
-	if (count >= *maxlen)
-		return VDO_UNEXPECTED_EOF;
-	return VDO_SUCCESS;
 }
 
-static int write_block_allocator_statistics(char *prefix,
-					    struct block_allocator_statistics *stats,
-					    char *suffix, char **buf,
-					    unsigned int *maxlen)
+static void write_block_allocator_statistics(char *prefix,
+					     struct block_allocator_statistics *stats,
+					     char *suffix, char **buf,
+					     unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* The total number of slabs from which blocks may be allocated */
-	result = write_u64("slabCount : ", stats->slab_count, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("slabCount : ", stats->slab_count, ", ", buf, maxlen);
 	/* The total number of slabs from which blocks have ever been allocated */
-	result = write_u64("slabsOpened : ", stats->slabs_opened, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("slabsOpened : ", stats->slabs_opened, ", ", buf, maxlen);
 	/* The number of times since loading that a slab has been re-opened */
-	result = write_u64("slabsReopened : ", stats->slabs_reopened, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u64("slabsReopened : ", stats->slabs_reopened, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_commit_statistics(char *prefix, struct commit_statistics *stats,
-				   char *suffix, char **buf, unsigned int *maxlen)
+static void write_commit_statistics(char *prefix, struct commit_statistics *stats,
+				    char *suffix, char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* The total number of items on which processing has started */
-	result = write_u64("started : ", stats->started, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("started : ", stats->started, ", ", buf, maxlen);
 	/* The total number of items for which a write operation has been issued */
-	result = write_u64("written : ", stats->written, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("written : ", stats->written, ", ", buf, maxlen);
 	/* The total number of items for which a write operation has completed */
-	result = write_u64("committed : ", stats->committed, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u64("committed : ", stats->committed, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_recovery_journal_statistics(char *prefix,
-					     struct recovery_journal_statistics *stats,
-					     char *suffix, char **buf,
-					     unsigned int *maxlen)
+static void write_recovery_journal_statistics(char *prefix,
+					      struct recovery_journal_statistics *stats,
+					      char *suffix, char **buf,
+					      unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* Number of times the on-disk journal was full */
-	result = write_u64("diskFull : ", stats->disk_full, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("diskFull : ", stats->disk_full, ", ", buf, maxlen);
 	/* Number of times the recovery journal requested slab journal commits. */
-	result = write_u64("slabJournalCommitsRequested : ",
-			   stats->slab_journal_commits_requested, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("slabJournalCommitsRequested : ",
+		  stats->slab_journal_commits_requested, ", ", buf, maxlen);
 	/* Write/Commit totals for individual journal entries */
-	result = write_commit_statistics("entries : ", &stats->entries, ", ", buf,
-					 maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_commit_statistics("entries : ", &stats->entries, ", ", buf, maxlen);
 	/* Write/Commit totals for journal blocks */
-	result = write_commit_statistics("blocks : ", &stats->blocks, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_commit_statistics("blocks : ", &stats->blocks, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_packer_statistics(char *prefix, struct packer_statistics *stats,
-				   char *suffix, char **buf, unsigned int *maxlen)
+static void write_packer_statistics(char *prefix, struct packer_statistics *stats,
+				    char *suffix, char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* Number of compressed data items written since startup */
-	result = write_u64("compressedFragmentsWritten : ",
-			   stats->compressed_fragments_written, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("compressedFragmentsWritten : ",
+		  stats->compressed_fragments_written, ", ", buf, maxlen);
 	/* Number of blocks containing compressed items written since startup */
-	result = write_u64("compressedBlocksWritten : ",
-			   stats->compressed_blocks_written, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("compressedBlocksWritten : ",
+		  stats->compressed_blocks_written, ", ", buf, maxlen);
 	/* Number of VIOs that are pending in the packer */
-	result = write_u64("compressedFragmentsInPacker : ",
-			   stats->compressed_fragments_in_packer, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u64("compressedFragmentsInPacker : ",
+		  stats->compressed_fragments_in_packer, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_slab_journal_statistics(char *prefix,
-					 struct slab_journal_statistics *stats,
-					 char *suffix, char **buf, unsigned int *maxlen)
+static void write_slab_journal_statistics(char *prefix,
+					  struct slab_journal_statistics *stats,
+					  char *suffix, char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* Number of times the on-disk journal was full */
-	result = write_u64("diskFullCount : ", stats->disk_full_count, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("diskFullCount : ", stats->disk_full_count, ", ", buf, maxlen);
 	/* Number of times an entry was added over the flush threshold */
-	result = write_u64("flushCount : ", stats->flush_count, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("flushCount : ", stats->flush_count, ", ", buf, maxlen);
 	/* Number of times an entry was added over the block threshold */
-	result = write_u64("blockedCount : ", stats->blocked_count, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("blockedCount : ", stats->blocked_count, ", ", buf, maxlen);
 	/* Number of times a tail block was written */
-	result = write_u64("blocksWritten : ", stats->blocks_written, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("blocksWritten : ", stats->blocks_written, ", ", buf, maxlen);
 	/* Number of times we had to wait for the tail to write */
-	result = write_u64("tailBusyCount : ", stats->tail_busy_count, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u64("tailBusyCount : ", stats->tail_busy_count, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_slab_summary_statistics(char *prefix,
-					 struct slab_summary_statistics *stats,
-					 char *suffix, char **buf, unsigned int *maxlen)
+static void write_slab_summary_statistics(char *prefix,
+					  struct slab_summary_statistics *stats,
+					  char *suffix, char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* Number of blocks written */
-	result = write_u64("blocksWritten : ", stats->blocks_written, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u64("blocksWritten : ", stats->blocks_written, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_ref_counts_statistics(char *prefix, struct ref_counts_statistics *stats,
-				       char *suffix, char **buf, unsigned int *maxlen)
+static void write_ref_counts_statistics(char *prefix, struct ref_counts_statistics *stats,
+					char *suffix, char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* Number of reference blocks written */
-	result = write_u64("blocksWritten : ", stats->blocks_written, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u64("blocksWritten : ", stats->blocks_written, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_block_map_statistics(char *prefix, struct block_map_statistics *stats,
-				      char *suffix, char **buf, unsigned int *maxlen)
+static void write_block_map_statistics(char *prefix, struct block_map_statistics *stats,
+				       char *suffix, char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* number of dirty (resident) pages */
-	result = write_u32("dirtyPages : ", stats->dirty_pages, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u32("dirtyPages : ", stats->dirty_pages, ", ", buf, maxlen);
 	/* number of clean (resident) pages */
-	result = write_u32("cleanPages : ", stats->clean_pages, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u32("cleanPages : ", stats->clean_pages, ", ", buf, maxlen);
 	/* number of free pages */
-	result = write_u32("freePages : ", stats->free_pages, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u32("freePages : ", stats->free_pages, ", ", buf, maxlen);
 	/* number of pages in failed state */
-	result = write_u32("failedPages : ", stats->failed_pages, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u32("failedPages : ", stats->failed_pages, ", ", buf, maxlen);
 	/* number of pages incoming */
-	result = write_u32("incomingPages : ", stats->incoming_pages, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u32("incomingPages : ", stats->incoming_pages, ", ", buf, maxlen);
 	/* number of pages outgoing */
-	result = write_u32("outgoingPages : ", stats->outgoing_pages, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u32("outgoingPages : ", stats->outgoing_pages, ", ", buf, maxlen);
 	/* how many times free page not avail */
-	result = write_u32("cachePressure : ", stats->cache_pressure, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u32("cachePressure : ", stats->cache_pressure, ", ", buf, maxlen);
 	/* number of get_vdo_page() calls for read */
-	result = write_u64("readCount : ", stats->read_count, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("readCount : ", stats->read_count, ", ", buf, maxlen);
 	/* number of get_vdo_page() calls for write */
-	result = write_u64("writeCount : ", stats->write_count, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("writeCount : ", stats->write_count, ", ", buf, maxlen);
 	/* number of times pages failed to read */
-	result = write_u64("failedReads : ", stats->failed_reads, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("failedReads : ", stats->failed_reads, ", ", buf, maxlen);
 	/* number of times pages failed to write */
-	result = write_u64("failedWrites : ", stats->failed_writes, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("failedWrites : ", stats->failed_writes, ", ", buf, maxlen);
 	/* number of gets that are reclaimed */
-	result = write_u64("reclaimed : ", stats->reclaimed, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("reclaimed : ", stats->reclaimed, ", ", buf, maxlen);
 	/* number of gets for outgoing pages */
-	result = write_u64("readOutgoing : ", stats->read_outgoing, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("readOutgoing : ", stats->read_outgoing, ", ", buf, maxlen);
 	/* number of gets that were already there */
-	result = write_u64("foundInCache : ", stats->found_in_cache, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("foundInCache : ", stats->found_in_cache, ", ", buf, maxlen);
 	/* number of gets requiring discard */
-	result = write_u64("discardRequired : ", stats->discard_required, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("discardRequired : ", stats->discard_required, ", ", buf, maxlen);
 	/* number of gets enqueued for their page */
-	result = write_u64("waitForPage : ", stats->wait_for_page, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("waitForPage : ", stats->wait_for_page, ", ", buf, maxlen);
 	/* number of gets that have to fetch */
-	result = write_u64("fetchRequired : ", stats->fetch_required, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("fetchRequired : ", stats->fetch_required, ", ", buf, maxlen);
 	/* number of page fetches */
-	result = write_u64("pagesLoaded : ", stats->pages_loaded, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("pagesLoaded : ", stats->pages_loaded, ", ", buf, maxlen);
 	/* number of page saves */
-	result = write_u64("pagesSaved : ", stats->pages_saved, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("pagesSaved : ", stats->pages_saved, ", ", buf, maxlen);
 	/* the number of flushes issued */
-	result = write_u64("flushCount : ", stats->flush_count, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u64("flushCount : ", stats->flush_count, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_hash_lock_statistics(char *prefix, struct hash_lock_statistics *stats,
-				      char *suffix, char **buf, unsigned int *maxlen)
+static void write_hash_lock_statistics(char *prefix, struct hash_lock_statistics *stats,
+				       char *suffix, char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* Number of times the UDS advice proved correct */
-	result = write_u64("dedupeAdviceValid : ", stats->dedupe_advice_valid, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("dedupeAdviceValid : ", stats->dedupe_advice_valid, ", ", buf, maxlen);
 	/* Number of times the UDS advice proved incorrect */
-	result = write_u64("dedupeAdviceStale : ", stats->dedupe_advice_stale, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("dedupeAdviceStale : ", stats->dedupe_advice_stale, ", ", buf, maxlen);
 	/* Number of writes with the same data as another in-flight write */
-	result = write_u64("concurrentDataMatches : ", stats->concurrent_data_matches,
-			   ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("concurrentDataMatches : ", stats->concurrent_data_matches,
+		  ", ", buf, maxlen);
 	/* Number of writes whose hash collided with an in-flight write */
-	result = write_u64("concurrentHashCollisions : ",
-			   stats->concurrent_hash_collisions, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("concurrentHashCollisions : ",
+		  stats->concurrent_hash_collisions, ", ", buf, maxlen);
 	/* Current number of dedupe queries that are in flight */
-	result = write_u32("currDedupeQueries : ", stats->curr_dedupe_queries, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u32("currDedupeQueries : ", stats->curr_dedupe_queries, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_error_statistics(char *prefix, struct error_statistics *stats,
-				  char *suffix, char **buf, unsigned int *maxlen)
+static void write_error_statistics(char *prefix, struct error_statistics *stats,
+				   char *suffix, char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* number of times VDO got an invalid dedupe advice PBN from UDS */
-	result = write_u64("invalidAdvicePBNCount : ", stats->invalid_advice_pbn_count,
-			   ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("invalidAdvicePBNCount : ", stats->invalid_advice_pbn_count,
+		  ", ", buf, maxlen);
 	/* number of times a VIO completed with a VDO_NO_SPACE error */
-	result = write_u64("noSpaceErrorCount : ", stats->no_space_error_count, ", ",
-			   buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("noSpaceErrorCount : ", stats->no_space_error_count, ", ",
+		  buf, maxlen);
 	/* number of times a VIO completed with a VDO_READ_ONLY error */
-	result = write_u64("readOnlyErrorCount : ", stats->read_only_error_count, ", ",
-			   buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u64("readOnlyErrorCount : ", stats->read_only_error_count, ", ",
+		  buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_bio_stats(char *prefix, struct bio_stats *stats, char *suffix,
-			   char **buf, unsigned int *maxlen)
+static void write_bio_stats(char *prefix, struct bio_stats *stats, char *suffix,
+			    char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* Number of REQ_OP_READ bios */
-	result = write_u64("read : ", stats->read, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("read : ", stats->read, ", ", buf, maxlen);
 	/* Number of REQ_OP_WRITE bios with data */
-	result = write_u64("write : ", stats->write, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("write : ", stats->write, ", ", buf, maxlen);
 	/* Number of bios tagged with REQ_PREFLUSH and containing no data */
-	result = write_u64("emptyFlush : ", stats->empty_flush, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("emptyFlush : ", stats->empty_flush, ", ", buf, maxlen);
 	/* Number of REQ_OP_DISCARD bios */
-	result = write_u64("discard : ", stats->discard, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("discard : ", stats->discard, ", ", buf, maxlen);
 	/* Number of bios tagged with REQ_PREFLUSH */
-	result = write_u64("flush : ", stats->flush, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("flush : ", stats->flush, ", ", buf, maxlen);
 	/* Number of bios tagged with REQ_FUA */
-	result = write_u64("fua : ", stats->fua, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u64("fua : ", stats->fua, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_memory_usage(char *prefix, struct memory_usage *stats, char *suffix,
-			      char **buf, unsigned int *maxlen)
+static void write_memory_usage(char *prefix, struct memory_usage *stats, char *suffix,
+			       char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* Tracked bytes currently allocated. */
-	result = write_u64("bytesUsed : ", stats->bytes_used, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("bytesUsed : ", stats->bytes_used, ", ", buf, maxlen);
 	/* Maximum tracked bytes allocated. */
-	result = write_u64("peakBytesUsed : ", stats->peak_bytes_used, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u64("peakBytesUsed : ", stats->peak_bytes_used, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_index_statistics(char *prefix, struct index_statistics *stats,
-				  char *suffix, char **buf, unsigned int *maxlen)
+static void write_index_statistics(char *prefix, struct index_statistics *stats,
+				   char *suffix, char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
 	/* Number of records stored in the index */
-	result = write_u64("entriesIndexed : ", stats->entries_indexed, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("entriesIndexed : ", stats->entries_indexed, ", ", buf, maxlen);
 	/* Number of post calls that found an existing entry */
-	result = write_u64("postsFound : ", stats->posts_found, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("postsFound : ", stats->posts_found, ", ", buf, maxlen);
 	/* Number of post calls that added a new entry */
-	result = write_u64("postsNotFound : ", stats->posts_not_found, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("postsNotFound : ", stats->posts_not_found, ", ", buf, maxlen);
 	/* Number of query calls that found an existing entry */
-	result = write_u64("queriesFound : ", stats->queries_found, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("queriesFound : ", stats->queries_found, ", ", buf, maxlen);
 	/* Number of query calls that added a new entry */
-	result = write_u64("queriesNotFound : ", stats->queries_not_found, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("queriesNotFound : ", stats->queries_not_found, ", ", buf, maxlen);
 	/* Number of update calls that found an existing entry */
-	result = write_u64("updatesFound : ", stats->updates_found, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("updatesFound : ", stats->updates_found, ", ", buf, maxlen);
 	/* Number of update calls that added a new entry */
-	result = write_u64("updatesNotFound : ", stats->updates_not_found, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("updatesNotFound : ", stats->updates_not_found, ", ", buf, maxlen);
 	/* Number of entries discarded */
-	result = write_u64("entriesDiscarded : ", stats->entries_discarded, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_u64("entriesDiscarded : ", stats->entries_discarded, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
-static int write_vdo_statistics(char *prefix, struct vdo_statistics *stats, char *suffix,
-				char **buf, unsigned int *maxlen)
+static void write_vdo_statistics(char *prefix, struct vdo_statistics *stats, char *suffix,
+				 char **buf, unsigned int *maxlen)
 {
-	int result;
-
-	result = write_string(prefix, "{ ", NULL, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_u32("version : ", stats->version, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string(prefix, "{ ", NULL, buf, maxlen);
+	write_u32("version : ", stats->version, ", ", buf, maxlen);
 	/* Number of blocks used for data */
-	result = write_u64("dataBlocksUsed : ", stats->data_blocks_used, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("dataBlocksUsed : ", stats->data_blocks_used, ", ", buf, maxlen);
 	/* Number of blocks used for VDO metadata */
-	result = write_u64("overheadBlocksUsed : ", stats->overhead_blocks_used, ", ",
-			   buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("overheadBlocksUsed : ", stats->overhead_blocks_used, ", ",
+		  buf, maxlen);
 	/* Number of logical blocks that are currently mapped to physical blocks */
-	result = write_u64("logicalBlocksUsed : ", stats->logical_blocks_used, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("logicalBlocksUsed : ", stats->logical_blocks_used, ", ", buf, maxlen);
 	/* number of physical blocks */
-	result = write_block_count_t("physicalBlocks : ", stats->physical_blocks, ", ",
-				     buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_block_count_t("physicalBlocks : ", stats->physical_blocks, ", ",
+			    buf, maxlen);
 	/* number of logical blocks */
-	result = write_block_count_t("logicalBlocks : ", stats->logical_blocks, ", ",
-				     buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_block_count_t("logicalBlocks : ", stats->logical_blocks, ", ",
+			    buf, maxlen);
 	/* Size of the block map page cache, in bytes */
-	result = write_u64("blockMapCacheSize : ", stats->block_map_cache_size, ", ",
-			   buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("blockMapCacheSize : ", stats->block_map_cache_size, ", ",
+		  buf, maxlen);
 	/* The physical block size */
-	result = write_u64("blockSize : ", stats->block_size, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("blockSize : ", stats->block_size, ", ", buf, maxlen);
 	/* Number of times the VDO has successfully recovered */
-	result = write_u64("completeRecoveries : ", stats->complete_recoveries, ", ",
-			   buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("completeRecoveries : ", stats->complete_recoveries, ", ",
+		  buf, maxlen);
 	/* Number of times the VDO has recovered from read-only mode */
-	result = write_u64("readOnlyRecoveries : ", stats->read_only_recoveries, ", ",
-			   buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("readOnlyRecoveries : ", stats->read_only_recoveries, ", ",
+		  buf, maxlen);
 	/* String describing the operating mode of the VDO */
-	result = write_string("mode : ", stats->mode, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_string("mode : ", stats->mode, ", ", buf, maxlen);
 	/* Whether the VDO is in recovery mode */
-	result = write_bool("inRecoveryMode : ", stats->in_recovery_mode, ", ", buf,
-			    maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_bool("inRecoveryMode : ", stats->in_recovery_mode, ", ", buf, maxlen);
 	/* What percentage of recovery mode work has been completed */
-	result = write_u8("recoveryPercentage : ", stats->recovery_percentage, ", ", buf,
-			  maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u8("recoveryPercentage : ", stats->recovery_percentage, ", ", buf, maxlen);
 	/* The statistics for the compressed block packer */
-	result = write_packer_statistics("packer : ", &stats->packer, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_packer_statistics("packer : ", &stats->packer, ", ", buf, maxlen);
 	/* Counters for events in the block allocator */
-	result = write_block_allocator_statistics("allocator : ", &stats->allocator,
-						  ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_block_allocator_statistics("allocator : ", &stats->allocator,
+					 ", ", buf, maxlen);
 	/* Counters for events in the recovery journal */
-	result = write_recovery_journal_statistics("journal : ", &stats->journal, ", ",
-						   buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_recovery_journal_statistics("journal : ", &stats->journal, ", ",
+					  buf, maxlen);
 	/* The statistics for the slab journals */
-	result = write_slab_journal_statistics("slabJournal : ", &stats->slab_journal,
-					       ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_slab_journal_statistics("slabJournal : ", &stats->slab_journal,
+				      ", ", buf, maxlen);
 	/* The statistics for the slab summary */
-	result = write_slab_summary_statistics("slabSummary : ", &stats->slab_summary,
-					       ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_slab_summary_statistics("slabSummary : ", &stats->slab_summary,
+				      ", ", buf, maxlen);
 	/* The statistics for the reference counts */
-	result = write_ref_counts_statistics("refCounts : ", &stats->ref_counts, ", ",
-					     buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_ref_counts_statistics("refCounts : ", &stats->ref_counts, ", ",
+				    buf, maxlen);
 	/* The statistics for the block map */
-	result = write_block_map_statistics("blockMap : ", &stats->block_map, ", ", buf,
-					    maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_block_map_statistics("blockMap : ", &stats->block_map, ", ", buf, maxlen);
 	/* The dedupe statistics from hash locks */
-	result = write_hash_lock_statistics("hashLock : ", &stats->hash_lock, ", ", buf,
-					    maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_hash_lock_statistics("hashLock : ", &stats->hash_lock, ", ", buf, maxlen);
 	/* Counts of error conditions */
-	result = write_error_statistics("errors : ", &stats->errors, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_error_statistics("errors : ", &stats->errors, ", ", buf, maxlen);
 	/* The VDO instance */
-	result = write_u32("instance : ", stats->instance, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u32("instance : ", stats->instance, ", ", buf, maxlen);
 	/* Current number of active VIOs */
-	result = write_u32("currentVIOsInProgress : ", stats->current_vios_in_progress,
-			   ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u32("currentVIOsInProgress : ", stats->current_vios_in_progress,
+		  ", ", buf, maxlen);
 	/* Maximum number of active VIOs */
-	result = write_u32("maxVIOs : ", stats->max_vios, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u32("maxVIOs : ", stats->max_vios, ", ", buf, maxlen);
 	/* Number of times the UDS index was too slow in responding */
-	result = write_u64("dedupeAdviceTimeouts : ", stats->dedupe_advice_timeouts,
-			   ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("dedupeAdviceTimeouts : ", stats->dedupe_advice_timeouts,
+		  ", ", buf, maxlen);
 	/* Number of flush requests submitted to the storage device */
-	result = write_u64("flushOut : ", stats->flush_out, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("flushOut : ", stats->flush_out, ", ", buf, maxlen);
 	/* Logical block size */
-	result = write_u64("logicalBlockSize : ", stats->logical_block_size, ", ", buf,
-			   maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_u64("logicalBlockSize : ", stats->logical_block_size, ", ", buf, maxlen);
 	/* Bios submitted into VDO from above */
-	result = write_bio_stats("biosIn : ", &stats->bios_in, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_bio_stats("biosInPartial : ", &stats->bios_in_partial, ", ", buf,
-				 maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_bio_stats("biosIn : ", &stats->bios_in, ", ", buf, maxlen);
+	write_bio_stats("biosInPartial : ", &stats->bios_in_partial, ", ", buf, maxlen);
 	/* Bios submitted onward for user data */
-	result = write_bio_stats("biosOut : ", &stats->bios_out, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_bio_stats("biosOut : ", &stats->bios_out, ", ", buf, maxlen);
 	/* Bios submitted onward for metadata */
-	result = write_bio_stats("biosMeta : ", &stats->bios_meta, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_bio_stats("biosJournal : ", &stats->bios_journal, ", ", buf,
-				 maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_bio_stats("biosPageCache : ", &stats->bios_page_cache, ", ", buf,
-				 maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_bio_stats("biosOutCompleted : ", &stats->bios_out_completed, ", ",
-				 buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_bio_stats("biosMetaCompleted : ", &stats->bios_meta_completed,
-				 ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_bio_stats("biosJournalCompleted : ",
-				 &stats->bios_journal_completed, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_bio_stats("biosPageCacheCompleted : ",
-				 &stats->bios_page_cache_completed, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_bio_stats("biosAcknowledged : ", &stats->bios_acknowledged, ", ",
-				 buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_bio_stats("biosAcknowledgedPartial : ",
-				 &stats->bios_acknowledged_partial, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_bio_stats("biosMeta : ", &stats->bios_meta, ", ", buf, maxlen);
+	write_bio_stats("biosJournal : ", &stats->bios_journal, ", ", buf, maxlen);
+	write_bio_stats("biosPageCache : ", &stats->bios_page_cache, ", ", buf, maxlen);
+	write_bio_stats("biosOutCompleted : ", &stats->bios_out_completed, ", ",
+			buf, maxlen);
+	write_bio_stats("biosMetaCompleted : ", &stats->bios_meta_completed,
+			", ", buf, maxlen);
+	write_bio_stats("biosJournalCompleted : ",
+			&stats->bios_journal_completed, ", ", buf, maxlen);
+	write_bio_stats("biosPageCacheCompleted : ",
+			&stats->bios_page_cache_completed, ", ", buf, maxlen);
+	write_bio_stats("biosAcknowledged : ", &stats->bios_acknowledged, ", ",
+			buf, maxlen);
+	write_bio_stats("biosAcknowledgedPartial : ",
+			&stats->bios_acknowledged_partial, ", ", buf, maxlen);
 	/* Current number of bios in progress */
-	result = write_bio_stats("biosInProgress : ", &stats->bios_in_progress, ", ",
-				 buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_bio_stats("biosInProgress : ", &stats->bios_in_progress, ", ",
+			buf, maxlen);
 	/* Memory usage stats. */
-	result = write_memory_usage("memoryUsage : ", &stats->memory_usage, ", ", buf,
-				    maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
+	write_memory_usage("memoryUsage : ", &stats->memory_usage, ", ", buf, maxlen);
 	/* The statistics for the UDS index */
-	result = write_index_statistics("index : ", &stats->index, ", ", buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	result = write_string(NULL, "}", suffix, buf, maxlen);
-	if (result != VDO_SUCCESS)
-		return result;
-	return VDO_SUCCESS;
+	write_index_statistics("index : ", &stats->index, ", ", buf, maxlen);
+	write_string(NULL, "}", suffix, buf, maxlen);
 }
 
 int vdo_write_stats(struct vdo *vdo, char *buf, unsigned int maxlen)
@@ -762,11 +420,13 @@ int vdo_write_stats(struct vdo *vdo, char *buf, unsigned int maxlen)
 	int result;
 
 	result = uds_allocate(1, struct vdo_statistics, __func__, &stats);
-	if (result != VDO_SUCCESS)
+	if (result != UDS_SUCCESS) {
+		uds_log_error("Cannot allocate memory to write VDO statistics");
 		return result;
+	}
 
 	vdo_fetch_statistics(vdo, stats);
-	result = write_vdo_statistics(NULL, stats, NULL, &buf, &maxlen);
+	write_vdo_statistics(NULL, stats, NULL, &buf, &maxlen);
 	uds_free(stats);
-	return result;
+	return VDO_SUCCESS;
 }