iomap: invert the polarity of IOMAP_DIO_INLINE_COMP

Replace IOMAP_DIO_INLINE_COMP with a flag to indicate that the
completion should be offloaded.  This removes a tiny bit of boilerplate
code, but more importantly just makes the code easier to follow as this
new flag gets set most of the time and only cleared in one place, while
it was the inverse for the old version.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20251113170633.1453259-6-hch@lst.de
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: Christoph Hellwig

fs/iomap/direct-io.c

@@ -17,7 +17,7 @@
  * iomap.h:
  */
 #define IOMAP_DIO_NO_INVALIDATE	(1U << 26)
-#define IOMAP_DIO_INLINE_COMP	(1U << 27)
+#define IOMAP_DIO_COMP_WORK	(1U << 27)
 #define IOMAP_DIO_WRITE_THROUGH	(1U << 28)
 #define IOMAP_DIO_NEED_SYNC	(1U << 29)
 #define IOMAP_DIO_WRITE		(1U << 30)
@@ -182,7 +182,7 @@ static void iomap_dio_done(struct iomap_dio *dio)
 	 * for error handling.
 	 */
 	if (dio->error)
-		dio->flags &= ~IOMAP_DIO_INLINE_COMP;
+		dio->flags |= IOMAP_DIO_COMP_WORK;
 
 	/*
 	 * Never invalidate pages from this context to avoid deadlocks with
@@ -192,17 +192,14 @@ static void iomap_dio_done(struct iomap_dio *dio)
 	 * right between this check and the actual completion.
 	 */
 	if ((dio->flags & IOMAP_DIO_WRITE) &&
-	    (dio->flags & IOMAP_DIO_INLINE_COMP)) {
+	    !(dio->flags & IOMAP_DIO_COMP_WORK)) {
 		if (dio->iocb->ki_filp->f_mapping->nrpages)
-			dio->flags &= ~IOMAP_DIO_INLINE_COMP;
+			dio->flags |= IOMAP_DIO_COMP_WORK;
 		else
 			dio->flags |= IOMAP_DIO_NO_INVALIDATE;
 	}
 
-	if (dio->flags & IOMAP_DIO_INLINE_COMP) {
-		WRITE_ONCE(iocb->private, NULL);
-		iomap_dio_complete_work(&dio->aio.work);
-	} else {
+	if (dio->flags & IOMAP_DIO_COMP_WORK) {
 		struct inode *inode = file_inode(iocb->ki_filp);
 
 		/*
@@ -213,7 +210,11 @@ static void iomap_dio_done(struct iomap_dio *dio)
 		 */
 		INIT_WORK(&dio->aio.work, iomap_dio_complete_work);
 		queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work);
+		return;
 	}
+
+	WRITE_ONCE(iocb->private, NULL);
+	iomap_dio_complete_work(&dio->aio.work);
 }
 
 void iomap_dio_bio_end_io(struct bio *bio)
@@ -251,7 +252,7 @@ u32 iomap_finish_ioend_direct(struct iomap_ioend *ioend)
 		 * that we are already called from the ioend completion
 		 * workqueue.
 		 */
-		dio->flags |= IOMAP_DIO_INLINE_COMP;
+		dio->flags &= ~IOMAP_DIO_COMP_WORK;
 		iomap_dio_done(dio);
 	}
 
@@ -399,7 +400,7 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio)
 		 * handled in __iomap_dio_rw().
 		 */
 		if (need_completion_work)
-			dio->flags &= ~IOMAP_DIO_INLINE_COMP;
+			dio->flags |= IOMAP_DIO_COMP_WORK;
 
 		bio_opf |= REQ_OP_WRITE;
 	} else {
@@ -422,7 +423,7 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio)
 	 * ones we set for inline and deferred completions. If none of those
 	 * are available for this IO, clear the polled flag.
 	 */
-	if (!(dio->flags & IOMAP_DIO_INLINE_COMP))
+	if (dio->flags & IOMAP_DIO_COMP_WORK)
 		dio->iocb->ki_flags &= ~IOCB_HIPRI;
 
 	if (need_zeroout) {
@@ -661,12 +662,6 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 	if (dio_flags & IOMAP_DIO_FSBLOCK_ALIGNED)
 		dio->flags |= IOMAP_DIO_FSBLOCK_ALIGNED;
 
-	/*
-	 * Try to complete inline if we can.  For reads this is always possible,
-	 * but for writes we'll end up clearing this more often than not.
-	 */
-	dio->flags |= IOMAP_DIO_INLINE_COMP;
-
 	if (iov_iter_rw(iter) == READ) {
 		if (iomi.pos >= dio->i_size)
 			goto out_free_dio;
@@ -713,7 +708,7 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 		 * i_size updates must to happen from process context.
 		 */
 		if (iomi.pos + iomi.len > dio->i_size)
-			dio->flags &= ~IOMAP_DIO_INLINE_COMP;
+			dio->flags |= IOMAP_DIO_COMP_WORK;
 
 		/*
 		 * Try to invalidate cache pages for the range we are writing.
@@ -794,7 +789,7 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 	if (dio->flags & IOMAP_DIO_WRITE_THROUGH)
 		dio->flags &= ~IOMAP_DIO_NEED_SYNC;
 	else if (dio->flags & IOMAP_DIO_NEED_SYNC)
-		dio->flags &= ~IOMAP_DIO_INLINE_COMP;
+		dio->flags |= IOMAP_DIO_COMP_WORK;
 
 	/*
 	 * We are about to drop our additional submission reference, which