Update types in smgr API

Change data buffer to void *, from char *, and add const where
appropriate.  This makes it match the File API (see also
2d4f1ba6cfc2f0a977f1c30bda9848041343e248) and stdio.

Discussion: https://www.postgresql.org/message-id/flat/11dda853-bb5b-59ba-a746-e168b1ce4bdb%40enterprisedb.com

contrib/bloom/blinsert.c

@@ -178,7 +178,7 @@ blbuildempty(Relation index)
 	 */
 	PageSetChecksumInplace(metapage, BLOOM_METAPAGE_BLKNO);
 	smgrwrite(RelationGetSmgr(index), INIT_FORKNUM, BLOOM_METAPAGE_BLKNO,
-			  (char *) metapage, true);
+			  metapage, true);
 	log_newpage(&(RelationGetSmgr(index))->smgr_rlocator.locator, INIT_FORKNUM,
 				BLOOM_METAPAGE_BLKNO, metapage, true);
 

src/backend/access/heap/rewriteheap.c

@@ -326,7 +326,7 @@ end_heap_rewrite(RewriteState state)
 		PageSetChecksumInplace(state->rs_buffer, state->rs_blockno);
 
 		smgrextend(RelationGetSmgr(state->rs_new_rel), MAIN_FORKNUM,
-				   state->rs_blockno, (char *) state->rs_buffer, true);
+				   state->rs_blockno, state->rs_buffer, true);
 	}
 
 	/*
@@ -692,7 +692,7 @@ raw_heap_insert(RewriteState state, HeapTuple tup)
 			PageSetChecksumInplace(page, state->rs_blockno);
 
 			smgrextend(RelationGetSmgr(state->rs_new_rel), MAIN_FORKNUM,
-					   state->rs_blockno, (char *) page, true);
+					   state->rs_blockno, page, true);
 
 			state->rs_blockno++;
 			state->rs_buffer_valid = false;

src/backend/access/nbtree/nbtree.c

@@ -165,7 +165,7 @@ btbuildempty(Relation index)
 	 */
 	PageSetChecksumInplace(metapage, BTREE_METAPAGE);
 	smgrwrite(RelationGetSmgr(index), INIT_FORKNUM, BTREE_METAPAGE,
-			  (char *) metapage, true);
+			  metapage, true);
 	log_newpage(&RelationGetSmgr(index)->smgr_rlocator.locator, INIT_FORKNUM,
 				BTREE_METAPAGE, metapage, true);
 

src/backend/access/nbtree/nbtsort.c

@@ -664,7 +664,7 @@ _bt_blwritepage(BTWriteState *wstate, Page page, BlockNumber blkno)
 		/* don't set checksum for all-zero page */
 		smgrextend(RelationGetSmgr(wstate->index), MAIN_FORKNUM,
 				   wstate->btws_pages_written++,
-				   (char *) wstate->btws_zeropage,
+				   wstate->btws_zeropage,
 				   true);
 	}
 
@@ -678,14 +678,14 @@ _bt_blwritepage(BTWriteState *wstate, Page page, BlockNumber blkno)
 	{
 		/* extending the file... */
 		smgrextend(RelationGetSmgr(wstate->index), MAIN_FORKNUM, blkno,
-				   (char *) page, true);
+				   page, true);
 		wstate->btws_pages_written++;
 	}
 	else
 	{
 		/* overwriting a block we zero-filled before */
 		smgrwrite(RelationGetSmgr(wstate->index), MAIN_FORKNUM, blkno,
-				  (char *) page, true);
+				  page, true);
 	}
 
 	pfree(page);

src/backend/access/spgist/spginsert.c

@@ -170,7 +170,7 @@ spgbuildempty(Relation index)
 	 */
 	PageSetChecksumInplace(page, SPGIST_METAPAGE_BLKNO);
 	smgrwrite(RelationGetSmgr(index), INIT_FORKNUM, SPGIST_METAPAGE_BLKNO,
-			  (char *) page, true);
+			  page, true);
 	log_newpage(&(RelationGetSmgr(index))->smgr_rlocator.locator, INIT_FORKNUM,
 				SPGIST_METAPAGE_BLKNO, page, true);
 
@@ -179,7 +179,7 @@ spgbuildempty(Relation index)
 
 	PageSetChecksumInplace(page, SPGIST_ROOT_BLKNO);
 	smgrwrite(RelationGetSmgr(index), INIT_FORKNUM, SPGIST_ROOT_BLKNO,
-			  (char *) page, true);
+			  page, true);
 	log_newpage(&(RelationGetSmgr(index))->smgr_rlocator.locator, INIT_FORKNUM,
 				SPGIST_ROOT_BLKNO, page, true);
 
@@ -188,7 +188,7 @@ spgbuildempty(Relation index)
 
 	PageSetChecksumInplace(page, SPGIST_NULL_BLKNO);
 	smgrwrite(RelationGetSmgr(index), INIT_FORKNUM, SPGIST_NULL_BLKNO,
-			  (char *) page, true);
+			  page, true);
 	log_newpage(&(RelationGetSmgr(index))->smgr_rlocator.locator, INIT_FORKNUM,
 				SPGIST_NULL_BLKNO, page, true);
 

src/backend/storage/buffer/bufmgr.c

@@ -1003,7 +1003,7 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 		/* new buffers are zero-filled */
 		MemSet((char *) bufBlock, 0, BLCKSZ);
 		/* don't set checksum for all-zero page */
-		smgrextend(smgr, forkNum, blockNum, (char *) bufBlock, false);
+		smgrextend(smgr, forkNum, blockNum, bufBlock, false);
 
 		pgstat_count_io_op(io_object, io_context, IOOP_EXTEND);
 
@@ -1032,7 +1032,7 @@ ReadBuffer_common(SMgrRelation smgr, char relpersistence, ForkNumber forkNum,
 			else
 				INSTR_TIME_SET_ZERO(io_start);
 
-			smgrread(smgr, forkNum, blockNum, (char *) bufBlock);
+			smgrread(smgr, forkNum, blockNum, bufBlock);
 
 			pgstat_count_io_op(io_object, io_context, IOOP_READ);
 

src/backend/storage/smgr/md.c

@@ -447,7 +447,7 @@ mdunlinkfork(RelFileLocatorBackend rlocator, ForkNumber forknum, bool isRedo)
  */
 void
 mdextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		 char *buffer, bool skipFsync)
+		 const void *buffer, bool skipFsync)
 {
 	off_t		seekpos;
 	int			nbytes;
@@ -669,7 +669,7 @@ mdwriteback(SMgrRelation reln, ForkNumber forknum,
  */
 void
 mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-	   char *buffer)
+	   void *buffer)
 {
 	off_t		seekpos;
 	int			nbytes;
@@ -734,7 +734,7 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
  */
 void
 mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		char *buffer, bool skipFsync)
+		const void *buffer, bool skipFsync)
 {
 	off_t		seekpos;
 	int			nbytes;

src/backend/storage/smgr/smgr.c

@@ -49,13 +49,13 @@ typedef struct f_smgr
 	void		(*smgr_unlink) (RelFileLocatorBackend rlocator, ForkNumber forknum,
 								bool isRedo);
 	void		(*smgr_extend) (SMgrRelation reln, ForkNumber forknum,
-								BlockNumber blocknum, char *buffer, bool skipFsync);
+								BlockNumber blocknum, const void *buffer, bool skipFsync);
 	bool		(*smgr_prefetch) (SMgrRelation reln, ForkNumber forknum,
 								  BlockNumber blocknum);
 	void		(*smgr_read) (SMgrRelation reln, ForkNumber forknum,
-							  BlockNumber blocknum, char *buffer);
+							  BlockNumber blocknum, void *buffer);
 	void		(*smgr_write) (SMgrRelation reln, ForkNumber forknum,
-							   BlockNumber blocknum, char *buffer, bool skipFsync);
+							   BlockNumber blocknum, const void *buffer, bool skipFsync);
 	void		(*smgr_writeback) (SMgrRelation reln, ForkNumber forknum,
 								   BlockNumber blocknum, BlockNumber nblocks);
 	BlockNumber (*smgr_nblocks) (SMgrRelation reln, ForkNumber forknum);
@@ -491,7 +491,7 @@ smgrdounlinkall(SMgrRelation *rels, int nrels, bool isRedo)
  */
 void
 smgrextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		   char *buffer, bool skipFsync)
+		   const void *buffer, bool skipFsync)
 {
 	smgrsw[reln->smgr_which].smgr_extend(reln, forknum, blocknum,
 										 buffer, skipFsync);
@@ -530,7 +530,7 @@ smgrprefetch(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum)
  */
 void
 smgrread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		 char *buffer)
+		 void *buffer)
 {
 	smgrsw[reln->smgr_which].smgr_read(reln, forknum, blocknum, buffer);
 }
@@ -552,7 +552,7 @@ smgrread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
  */
 void
 smgrwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		  char *buffer, bool skipFsync)
+		  const void *buffer, bool skipFsync)
 {
 	smgrsw[reln->smgr_which].smgr_write(reln, forknum, blocknum,
 										buffer, skipFsync);

src/include/storage/md.h

@@ -27,13 +27,13 @@ extern void mdcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
 extern bool mdexists(SMgrRelation reln, ForkNumber forknum);
 extern void mdunlink(RelFileLocatorBackend rlocator, ForkNumber forknum, bool isRedo);
 extern void mdextend(SMgrRelation reln, ForkNumber forknum,
-					 BlockNumber blocknum, char *buffer, bool skipFsync);
+					 BlockNumber blocknum, const void *buffer, bool skipFsync);
 extern bool mdprefetch(SMgrRelation reln, ForkNumber forknum,
 					   BlockNumber blocknum);
 extern void mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-				   char *buffer);
+				   void *buffer);
 extern void mdwrite(SMgrRelation reln, ForkNumber forknum,
-					BlockNumber blocknum, char *buffer, bool skipFsync);
+					BlockNumber blocknum, const void *buffer, bool skipFsync);
 extern void mdwriteback(SMgrRelation reln, ForkNumber forknum,
 						BlockNumber blocknum, BlockNumber nblocks);
 extern BlockNumber mdnblocks(SMgrRelation reln, ForkNumber forknum);

src/include/storage/smgr.h

@@ -91,13 +91,13 @@ extern void smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
 extern void smgrdosyncall(SMgrRelation *rels, int nrels);
 extern void smgrdounlinkall(SMgrRelation *rels, int nrels, bool isRedo);
 extern void smgrextend(SMgrRelation reln, ForkNumber forknum,
-					   BlockNumber blocknum, char *buffer, bool skipFsync);
+					   BlockNumber blocknum, const void *buffer, bool skipFsync);
 extern bool smgrprefetch(SMgrRelation reln, ForkNumber forknum,
 						 BlockNumber blocknum);
 extern void smgrread(SMgrRelation reln, ForkNumber forknum,
-					 BlockNumber blocknum, char *buffer);
+					 BlockNumber blocknum, void *buffer);
 extern void smgrwrite(SMgrRelation reln, ForkNumber forknum,
-					  BlockNumber blocknum, char *buffer, bool skipFsync);
+					  BlockNumber blocknum, const void *buffer, bool skipFsync);
 extern void smgrwriteback(SMgrRelation reln, ForkNumber forknum,
 						  BlockNumber blocknum, BlockNumber nblocks);
 extern BlockNumber smgrnblocks(SMgrRelation reln, ForkNumber forknum);