Remove unnecessary function parameters

trx_rseg_get_nth_undo(), trx_rsegf_undo_find_free():
Add a const qualifier, and remove the unused parameter mtr_t*.

storage/innobase/include/trx0rseg.h

@@ -57,16 +57,6 @@ trx_rsegf_get_new(
 	mtr_t*			mtr);
 
 /***************************************************************//**
-Gets the file page number of the nth undo log slot.
-@return page number of the undo log segment */
-UNIV_INLINE
-ulint
-trx_rsegf_get_nth_undo(
-/*===================*/
-	trx_rsegf_t*	rsegf,	/*!< in: rollback segment header */
-	ulint		n,	/*!< in: index of slot */
-	mtr_t*		mtr);	/*!< in: mtr */
-/***************************************************************//**
 Sets the file page number of the nth undo log slot. */
 UNIV_INLINE
 void
@@ -81,10 +71,7 @@ Looks for a free slot for an undo log segment.
 @return slot index or ULINT_UNDEFINED if not found */
 UNIV_INLINE
 ulint
-trx_rsegf_undo_find_free(
-/*=====================*/
-	trx_rsegf_t*	rsegf,	/*!< in: rollback segment header */
-	mtr_t*		mtr);	/*!< in: mtr */
+trx_rsegf_undo_find_free(const trx_rsegf_t* rsegf);
 
 /** Creates a rollback segment header.
 This function is called only when a new rollback segment is created in
@@ -243,6 +230,18 @@ struct trx_rseg_t {
 					/* Undo log segment slots */
 /*-------------------------------------------------------------*/
 
+/** Read the page number of an undo log slot.
+@param[in]	rsegf	rollback segment header
+@param[in]	n	slot number */
+inline
+uint32_t
+trx_rsegf_get_nth_undo(const trx_rsegf_t* rsegf, ulint n)
+{
+	ut_ad(n < TRX_RSEG_N_SLOTS);
+	return mach_read_from_4(rsegf + TRX_RSEG_UNDO_SLOTS
+				+ n * TRX_RSEG_SLOT_SIZE);
+}
+
 #include "trx0rseg.ic"
 
 #endif

storage/innobase/include/trx0rseg.ic

@@ -85,23 +85,6 @@ trx_rsegf_get_new(
 	return(header);
 }
 
-/***************************************************************//**
-Gets the file page number of the nth undo log slot.
-@return page number of the undo log segment */
-UNIV_INLINE
-ulint
-trx_rsegf_get_nth_undo(
-/*===================*/
-	trx_rsegf_t*	rsegf,	/*!< in: rollback segment header */
-	ulint		n,	/*!< in: index of slot */
-	mtr_t*		mtr)	/*!< in: mtr */
-{
-	ut_a(n < TRX_RSEG_N_SLOTS);
-
-	return(mtr_read_ulint(rsegf + TRX_RSEG_UNDO_SLOTS
-			      + n * TRX_RSEG_SLOT_SIZE, MLOG_4BYTES, mtr));
-}
-
 /***************************************************************//**
 Sets the file page number of the nth undo log slot. */
 UNIV_INLINE
@@ -124,10 +107,7 @@ Looks for a free slot for an undo log segment.
 @return slot index or ULINT_UNDEFINED if not found */
 UNIV_INLINE
 ulint
-trx_rsegf_undo_find_free(
-/*=====================*/
-	trx_rsegf_t*	rsegf,	/*!< in: rollback segment header */
-	mtr_t*		mtr)	/*!< in: mtr */
+trx_rsegf_undo_find_free(const trx_rsegf_t* rsegf)
 {
 	ulint		i;
 	ulint		page_no;
@@ -141,7 +121,7 @@ trx_rsegf_undo_find_free(
 #endif
 
 	for (i = 0; i < max_slots; i++) {
-		page_no = trx_rsegf_get_nth_undo(rsegf, i, mtr);
+		page_no = trx_rsegf_get_nth_undo(rsegf, i);
 
 		if (page_no == FIL_NULL) {
 			return(i);

storage/innobase/trx/trx0undo.cc

@@ -433,7 +433,7 @@ trx_undo_seg_create(trx_rsegf_t* rseg_hdr, ulint* id, dberr_t* err, mtr_t* mtr)
 	ulint		n_reserved;
 	bool		success;
 
-	slot_no = trx_rsegf_undo_find_free(rseg_hdr, mtr);
+	slot_no = trx_rsegf_undo_find_free(rseg_hdr);
 
 	if (slot_no == ULINT_UNDEFINED) {
 		ib::warn() << "Cannot find a free slot for an undo log. Do"
@@ -1150,9 +1150,7 @@ trx_undo_lists_init(
 	rseg_header = trx_rsegf_get_new(rseg->space, rseg->page_no, &mtr);
 
 	for (i = 0; i < TRX_RSEG_N_SLOTS; i++) {
-		ulint	page_no;
-
-		page_no = trx_rsegf_get_nth_undo(rseg_header, i, &mtr);
+		uint32_t page_no = trx_rsegf_get_nth_undo(rseg_header, i);
 
 		/* In forced recovery: try to avoid operations which look
 		at database pages; undo logs are rapidly changing data, and