Update parameter name context to wb_context

For clarity of review, renaming the function parameter "context" in
ScheduleBufferTagForWriteback() and IssuePendingWritebacks() to
"wb_context" is a separate commit. The next commit adds an "io_context"
parameter and "wb_context" makes it more clear which is which.

Author: Melanie Plageman <melanieplageman@gmail.com>
Discussion: https://postgr.es/m/CAAKRu_acc6iL4M3hvOTeztf_ZPpsB3Pqio5aVHgZ5q=Pi3BZKg@mail.gmail.com

src/backend/storage/buffer/bufmgr.c

@@ -5445,7 +5445,7 @@ WritebackContextInit(WritebackContext *context, int *max_pending)
  * Add buffer to list of pending writeback requests.
  */
 void
-ScheduleBufferTagForWriteback(WritebackContext *context, BufferTag *tag)
+ScheduleBufferTagForWriteback(WritebackContext *wb_context, BufferTag *tag)
 {
 	PendingWriteback *pending;
 
@@ -5456,11 +5456,11 @@ ScheduleBufferTagForWriteback(WritebackContext *context, BufferTag *tag)
 	 * Add buffer to the pending writeback array, unless writeback control is
 	 * disabled.
 	 */
-	if (*context->max_pending > 0)
+	if (*wb_context->max_pending > 0)
 	{
-		Assert(*context->max_pending <= WRITEBACK_MAX_PENDING_FLUSHES);
+		Assert(*wb_context->max_pending <= WRITEBACK_MAX_PENDING_FLUSHES);
 
-		pending = &context->pending_writebacks[context->nr_pending++];
+		pending = &wb_context->pending_writebacks[wb_context->nr_pending++];
 
 		pending->tag = *tag;
 	}
@@ -5470,8 +5470,8 @@ ScheduleBufferTagForWriteback(WritebackContext *context, BufferTag *tag)
 	 * includes the case where previously an item has been added, but control
 	 * is now disabled.
 	 */
-	if (context->nr_pending >= *context->max_pending)
-		IssuePendingWritebacks(context);
+	if (wb_context->nr_pending >= *wb_context->max_pending)
+		IssuePendingWritebacks(wb_context);
 }
 
 #define ST_SORT sort_pending_writebacks
@@ -5489,25 +5489,26 @@ ScheduleBufferTagForWriteback(WritebackContext *context, BufferTag *tag)
  * error out - it's just a hint.
  */
 void
-IssuePendingWritebacks(WritebackContext *context)
+IssuePendingWritebacks(WritebackContext *wb_context)
 {
 	int			i;
 
-	if (context->nr_pending == 0)
+	if (wb_context->nr_pending == 0)
 		return;
 
 	/*
 	 * Executing the writes in-order can make them a lot faster, and allows to
 	 * merge writeback requests to consecutive blocks into larger writebacks.
 	 */
-	sort_pending_writebacks(context->pending_writebacks, context->nr_pending);
+	sort_pending_writebacks(wb_context->pending_writebacks,
+							wb_context->nr_pending);
 
 	/*
 	 * Coalesce neighbouring writes, but nothing else. For that we iterate
 	 * through the, now sorted, array of pending flushes, and look forward to
 	 * find all neighbouring (or identical) writes.
 	 */
-	for (i = 0; i < context->nr_pending; i++)
+	for (i = 0; i < wb_context->nr_pending; i++)
 	{
 		PendingWriteback *cur;
 		PendingWriteback *next;
@@ -5517,7 +5518,7 @@ IssuePendingWritebacks(WritebackContext *context)
 		RelFileLocator currlocator;
 		Size		nblocks = 1;
 
-		cur = &context->pending_writebacks[i];
+		cur = &wb_context->pending_writebacks[i];
 		tag = cur->tag;
 		currlocator = BufTagGetRelFileLocator(&tag);
 
@@ -5525,10 +5526,10 @@ IssuePendingWritebacks(WritebackContext *context)
 		 * Peek ahead, into following writeback requests, to see if they can
 		 * be combined with the current one.
 		 */
-		for (ahead = 0; i + ahead + 1 < context->nr_pending; ahead++)
+		for (ahead = 0; i + ahead + 1 < wb_context->nr_pending; ahead++)
 		{
 
-			next = &context->pending_writebacks[i + ahead + 1];
+			next = &wb_context->pending_writebacks[i + ahead + 1];
 
 			/* different file, stop */
 			if (!RelFileLocatorEquals(currlocator,
@@ -5555,7 +5556,7 @@ IssuePendingWritebacks(WritebackContext *context)
 		smgrwriteback(reln, BufTagGetForkNum(&tag), tag.blockNum, nblocks);
 	}
 
-	context->nr_pending = 0;
+	wb_context->nr_pending = 0;
 }
 
 

src/include/storage/buf_internals.h

@@ -388,8 +388,8 @@ extern PGDLLIMPORT CkptSortItem *CkptBufferIds;
  */
 /* bufmgr.c */
 extern void WritebackContextInit(WritebackContext *context, int *max_pending);
-extern void IssuePendingWritebacks(WritebackContext *context);
-extern void ScheduleBufferTagForWriteback(WritebackContext *context, BufferTag *tag);
+extern void IssuePendingWritebacks(WritebackContext *wb_context);
+extern void ScheduleBufferTagForWriteback(WritebackContext *wb_context, BufferTag *tag);
 
 /* freelist.c */
 extern IOContext IOContextForStrategy(BufferAccessStrategy strategy);