xfs: move log discard work to xfs_discard.c

Because we are going to use the same list-based discard submission
interface for fstrim-based discards, too.

Signed-off-by: Dave Chinner <[e-mail]>
Reviewed-by: Darrick J. Wong <[e-mail]>

fs/xfs/xfs_discard.c

···
 // SPDX-License-Identifier: GPL-2.0
 /*
- * Copyright (C) 2010 Red Hat, Inc.
+ * Copyright (C) 2010, 2023 Red Hat, Inc.
  * All Rights Reserved.
  */
 #include "xfs.h"
···
 #include "xfs_trace.h"
 #include "xfs_log.h"
 #include "xfs_ag.h"
+
+struct workqueue_struct *xfs_discard_wq;
+
+static void
+xfs_discard_endio_work(
+	struct work_struct	*work)
+{
+	struct xfs_busy_extents	*extents =
+		container_of(work, struct xfs_busy_extents, endio_work);
+
+	xfs_extent_busy_clear(extents->mount, &extents->extent_list, false);
+	kmem_free(extents->owner);
+}
+
+/*
+ * Queue up the actual completion to a thread to avoid IRQ-safe locking for
+ * pagb_lock.
+ */
+static void
+xfs_discard_endio(
+	struct bio		*bio)
+{
+	struct xfs_busy_extents	*extents = bio->bi_private;
+
+	INIT_WORK(&extents->endio_work, xfs_discard_endio_work);
+	queue_work(xfs_discard_wq, &extents->endio_work);
+	bio_put(bio);
+}
+
+/*
+ * Walk the discard list and issue discards on all the busy extents in the
+ * list. We plug and chain the bios so that we only need a single completion
+ * call to clear all the busy extents once the discards are complete.
+ */
+int
+xfs_discard_extents(
+	struct xfs_mount	*mp,
+	struct xfs_busy_extents	*extents)
+{
+	struct xfs_extent_busy	*busyp;
+	struct bio		*bio = NULL;
+	struct blk_plug		plug;
+	int			error = 0;
+
+	blk_start_plug(&plug);
+	list_for_each_entry(busyp, &extents->extent_list, list) {
+		trace_xfs_discard_extent(mp, busyp->agno, busyp->bno,
+					 busyp->length);
+
+		error = __blkdev_issue_discard(mp->m_ddev_targp->bt_bdev,
+				XFS_AGB_TO_DADDR(mp, busyp->agno, busyp->bno),
+				XFS_FSB_TO_BB(mp, busyp->length),
+				GFP_NOFS, &bio);
+		if (error && error != -EOPNOTSUPP) {
+			xfs_info(mp,
+	 "discard failed for extent [0x%llx,%u], error %d",
+				 (unsigned long long)busyp->bno,
+				 busyp->length,
+				 error);
+			break;
+		}
+	}
+
+	if (bio) {
+		bio->bi_private = extents;
+		bio->bi_end_io = xfs_discard_endio;
+		submit_bio(bio);
+	} else {
+		xfs_discard_endio_work(&extents->endio_work);
+	}
+	blk_finish_plug(&plug);
+
+	return error;
+}
+
 
 STATIC int
 xfs_trim_extents(

fs/xfs/xfs_discard.h

···
 #define XFS_DISCARD_H 1
 
 struct fstrim_range;
-struct list_head;
+struct xfs_mount;
+struct xfs_busy_extents;
 
-extern int	xfs_ioc_trim(struct xfs_mount *, struct fstrim_range __user *);
+int xfs_discard_extents(struct xfs_mount *mp, struct xfs_busy_extents *busy);
+int xfs_ioc_trim(struct xfs_mount *mp, struct fstrim_range __user *fstrim);
 
 #endif /* XFS_DISCARD_H */

fs/xfs/xfs_extent_busy.h

···
 /*
  * Busy block/extent entry.  Indexed by a rbtree in perag to mark blocks that
  * have been freed but whose transactions aren't committed to disk yet.
- *
- * Note that we use the transaction ID to record the transaction, not the
- * transaction structure itself. See xfs_extent_busy_insert() for details.
  */
 struct xfs_extent_busy {
 	struct rb_node	rb_node;	/* ag by-bno indexed search tree */
···
 	unsigned int	flags;
 #define XFS_EXTENT_BUSY_DISCARDED	0x01	/* undergoing a discard op. */
 #define XFS_EXTENT_BUSY_SKIP_DISCARD	0x02	/* do not discard */
+};
+
+/*
+ * List used to track groups of related busy extents all the way through
+ * to discard completion.
+ */
+struct xfs_busy_extents {
+	struct xfs_mount	*mount;
+	struct list_head	extent_list;
+	struct work_struct	endio_work;
+
+	/*
+	 * Owner is the object containing the struct xfs_busy_extents to free
+	 * once the busy extents have been processed. If only the
+	 * xfs_busy_extents object needs freeing, then point this at itself.
+	 */
+	void			*owner;
 };
 
 void

fs/xfs/xfs_log_cil.c

···
 #include "xfs_log.h"
 #include "xfs_log_priv.h"
 #include "xfs_trace.h"
-
-struct workqueue_struct *xfs_discard_wq;
+#include "xfs_discard.h"
 
 /*
  * Allocate a new ticket. Failing to get a new ticket makes it really hard to
···
 
 	ctx = kmem_zalloc(sizeof(*ctx), KM_NOFS);
 	INIT_LIST_HEAD(&ctx->committing);
-	INIT_LIST_HEAD(&ctx->busy_extents);
+	INIT_LIST_HEAD(&ctx->busy_extents.extent_list);
 	INIT_LIST_HEAD(&ctx->log_items);
 	INIT_LIST_HEAD(&ctx->lv_chain);
 	INIT_WORK(&ctx->push_work, xlog_cil_push_work);
···
 
 		if (!list_empty(&cilpcp->busy_extents)) {
 			list_splice_init(&cilpcp->busy_extents,
-					&ctx->busy_extents);
+					&ctx->busy_extents.extent_list);
 		}
 		if (!list_empty(&cilpcp->log_items))
 			list_splice_init(&cilpcp->log_items, &ctx->log_items);
···
 	}
 }
 
-static void
-xlog_discard_endio_work(
-	struct work_struct	*work)
-{
-	struct xfs_cil_ctx	*ctx =
-		container_of(work, struct xfs_cil_ctx, discard_endio_work);
-	struct xfs_mount	*mp = ctx->cil->xc_log->l_mp;
-
-	xfs_extent_busy_clear(mp, &ctx->busy_extents, false);
-	kmem_free(ctx);
-}
-
-/*
- * Queue up the actual completion to a thread to avoid IRQ-safe locking for
- * pagb_lock.  Note that we need a unbounded workqueue, otherwise we might
- * get the execution delayed up to 30 seconds for weird reasons.
- */
-static void
-xlog_discard_endio(
-	struct bio		*bio)
-{
-	struct xfs_cil_ctx	*ctx = bio->bi_private;
-
-	INIT_WORK(&ctx->discard_endio_work, xlog_discard_endio_work);
-	queue_work(xfs_discard_wq, &ctx->discard_endio_work);
-	bio_put(bio);
-}
-
-static void
-xlog_discard_busy_extents(
-	struct xfs_mount	*mp,
-	struct xfs_cil_ctx	*ctx)
-{
-	struct list_head	*list = &ctx->busy_extents;
-	struct xfs_extent_busy	*busyp;
-	struct bio		*bio = NULL;
-	struct blk_plug		plug;
-	int			error = 0;
-
-	ASSERT(xfs_has_discard(mp));
-
-	blk_start_plug(&plug);
-	list_for_each_entry(busyp, list, list) {
-		trace_xfs_discard_extent(mp, busyp->agno, busyp->bno,
-					 busyp->length);
-
-		error = __blkdev_issue_discard(mp->m_ddev_targp->bt_bdev,
-				XFS_AGB_TO_DADDR(mp, busyp->agno, busyp->bno),
-				XFS_FSB_TO_BB(mp, busyp->length),
-				GFP_NOFS, &bio);
-		if (error && error != -EOPNOTSUPP) {
-			xfs_info(mp,
-	 "discard failed for extent [0x%llx,%u], error %d",
-				 (unsigned long long)busyp->bno,
-				 busyp->length,
-				 error);
-			break;
-		}
-	}
-
-	if (bio) {
-		bio->bi_private = ctx;
-		bio->bi_end_io = xlog_discard_endio;
-		submit_bio(bio);
-	} else {
-		xlog_discard_endio_work(&ctx->discard_endio_work);
-	}
-	blk_finish_plug(&plug);
-}
-
 /*
  * Mark all items committed and clear busy extents. We free the log vector
  * chains in a separate pass so that we unpin the log items as quickly as
···
 	xfs_trans_committed_bulk(ctx->cil->xc_log->l_ailp, &ctx->lv_chain,
 					ctx->start_lsn, abort);
 
-	xfs_extent_busy_sort(&ctx->busy_extents);
-	xfs_extent_busy_clear(mp, &ctx->busy_extents,
+	xfs_extent_busy_sort(&ctx->busy_extents.extent_list);
+	xfs_extent_busy_clear(mp, &ctx->busy_extents.extent_list,
 			      xfs_has_discard(mp) && !abort);
 
 	spin_lock(&ctx->cil->xc_push_lock);
···
 
 	xlog_cil_free_logvec(&ctx->lv_chain);
 
-	if (!list_empty(&ctx->busy_extents))
-		xlog_discard_busy_extents(mp, ctx);
-	else
-		kmem_free(ctx);
+	if (!list_empty(&ctx->busy_extents.extent_list)) {
+		ctx->busy_extents.mount = mp;
+		ctx->busy_extents.owner = ctx;
+		xfs_discard_extents(mp, &ctx->busy_extents);
+		return;
+	}
+
+	kmem_free(ctx);
 }
 
 void

fs/xfs/xfs_log_priv.h

···
 #ifndef	__XFS_LOG_PRIV_H__
 #define __XFS_LOG_PRIV_H__
 
+#include "xfs_extent_busy.h"	/* for struct xfs_busy_extents */
+
 struct xfs_buf;
 struct xlog;
 struct xlog_ticket;
···
 	struct xlog_in_core	*commit_iclog;
 	struct xlog_ticket	*ticket;	/* chkpt ticket */
 	atomic_t		space_used;	/* aggregate size of regions */
-	struct list_head	busy_extents;	/* busy extents in chkpt */
+	struct xfs_busy_extents	busy_extents;
 	struct list_head	log_items;	/* log items in chkpt */
 	struct list_head	lv_chain;	/* logvecs being pushed */
 	struct list_head	iclog_entry;
 	struct list_head	committing;	/* ctx committing list */
-	struct work_struct	discard_endio_work;
 	struct work_struct	push_work;
 	atomic_t		order_id;