fsi: Add regmap and refactor sbefifo

Merge series from Eddie James <eajames@linux.ibm.com>:

The SBEFIFO hardware can now be attached over a new I2C endpoint interface
called the I2C Responder (I2CR). In order to use the existing SBEFIFO
driver, add a regmap driver for the FSI bus and an endpoint driver for the
I2CR. Then, refactor the SBEFIFO and OCC drivers to clean up and use the
new regmap driver or the I2CR interface.

This branch just has the regmap change so it can be shared with the FSI
code.

1 files changed, 22 insertions, 7 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 176b432035ae..d01631d47806 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1598,14 +1598,19 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
 						write_bytes);
 			else
 				btrfs_check_nocow_unlock(BTRFS_I(inode));
+
+			if (nowait && ret == -ENOSPC)
+				ret = -EAGAIN;
 			break;
 		}
 
 		release_bytes = reserve_bytes;
 again:
 		ret = balance_dirty_pages_ratelimited_flags(inode->i_mapping, bdp_flags);
-		if (ret)
+		if (ret) {
+			btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes);
 			break;
+		}
 
 		/*
 		 * This is going to setup the pages array with the number of
@@ -1765,6 +1770,7 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
 	loff_t endbyte;
 	ssize_t err;
 	unsigned int ilock_flags = 0;
+	struct iomap_dio *dio;
 
 	if (iocb->ki_flags & IOCB_NOWAIT)
 		ilock_flags |= BTRFS_ILOCK_TRY;
@@ -1825,11 +1831,22 @@ relock:
 	 * So here we disable page faults in the iov_iter and then retry if we
 	 * got -EFAULT, faulting in the pages before the retry.
 	 */
-again:
 	from->nofault = true;
-	err = btrfs_dio_rw(iocb, from, written);
+	dio = btrfs_dio_write(iocb, from, written);
 	from->nofault = false;
 
+	/*
+	 * iomap_dio_complete() will call btrfs_sync_file() if we have a dsync
+	 * iocb, and that needs to lock the inode. So unlock it before calling
+	 * iomap_dio_complete() to avoid a deadlock.
+	 */
+	btrfs_inode_unlock(inode, ilock_flags);
+
+	if (IS_ERR_OR_NULL(dio))
+		err = PTR_ERR_OR_ZERO(dio);
+	else
+		err = iomap_dio_complete(dio);
+
 	/* No increment (+=) because iomap returns a cumulative value. */
 	if (err > 0)
 		written = err;
@@ -1855,12 +1872,10 @@ again:
 		} else {
 			fault_in_iov_iter_readable(from, left);
 			prev_left = left;
-			goto again;
+			goto relock;
 		}
 	}
 
-	btrfs_inode_unlock(inode, ilock_flags);
-
 	/*
 	 * If 'err' is -ENOTBLK or we have not written all data, then it means
 	 * we must fallback to buffered IO.
@@ -4035,7 +4050,7 @@ again:
 	 */
 	pagefault_disable();
 	to->nofault = true;
-	ret = btrfs_dio_rw(iocb, to, read);
+	ret = btrfs_dio_read(iocb, to, read);
 	to->nofault = false;
 	pagefault_enable();