[PATCH 4/9] xfs: make xfs_buf_get_uncached return an error code

["Darrick J. Wong" <darrick.wong@oracle.com>]

From: Darrick J. Wong <darrick.wong@oracle.com>

Convert xfs_buf_get_uncached() to return numeric error codes like most
everywhere else in xfs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/libxfs/xfs_ag.c |   21 ++++++++++++---------
 fs/xfs/xfs_buf.c       |   23 ++++++++++++++---------
 fs/xfs/xfs_buf.h       |    4 ++--
 3 files changed, 28 insertions(+), 20 deletions(-)


diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
index 14fbdf22b7e7..08d6beb54f8c 100644
--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -23,25 +23,28 @@
 #include "xfs_ag_resv.h"
 #include "xfs_health.h"
 
-static struct xfs_buf *
+static int
 xfs_get_aghdr_buf(
 	struct xfs_mount	*mp,
 	xfs_daddr_t		blkno,
 	size_t			numblks,
+	struct xfs_buf		**bpp,
 	const struct xfs_buf_ops *ops)
 {
 	struct xfs_buf		*bp;
+	int			error;
 
-	bp = xfs_buf_get_uncached(mp->m_ddev_targp, numblks, 0);
-	if (!bp)
-		return NULL;
+	error = xfs_buf_get_uncached(mp->m_ddev_targp, numblks, 0, &bp);
+	if (error)
+		return error;
 
 	xfs_buf_zero(bp, 0, BBTOB(bp->b_length));
 	bp->b_bn = blkno;
 	bp->b_maps[0].bm_bn = blkno;
 	bp->b_ops = ops;
 
-	return bp;
+	*bpp = bp;
+	return 0;
 }
 
 static inline bool is_log_ag(struct xfs_mount *mp, struct aghdr_init_data *id)
@@ -340,13 +343,13 @@ xfs_ag_init_hdr(
 	struct aghdr_init_data	*id,
 	aghdr_init_work_f	work,
 	const struct xfs_buf_ops *ops)
-
 {
 	struct xfs_buf		*bp;
+	int			error;
 
-	bp = xfs_get_aghdr_buf(mp, id->daddr, id->numblks, ops);
-	if (!bp)
-		return -ENOMEM;
+	error = xfs_get_aghdr_buf(mp, id->daddr, id->numblks, &bp, ops);
+	if (error)
+		return error;
 
 	(*work)(mp, bp, id);
 
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 643173cc58f6..a7d538b89bb5 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -932,12 +932,13 @@ xfs_buf_read_uncached(
 	const struct xfs_buf_ops *ops)
 {
 	struct xfs_buf		*bp;
+	int			error;
 
 	*bpp = NULL;
 
-	bp = xfs_buf_get_uncached(target, numblks, flags);
-	if (!bp)
-		return -ENOMEM;
+	error = xfs_buf_get_uncached(target, numblks, flags, &bp);
+	if (error)
+		return error;
 
 	/* set up the buffer for a read IO */
 	ASSERT(bp->b_map_count == 1);
@@ -948,7 +949,7 @@ xfs_buf_read_uncached(
 
 	xfs_buf_submit(bp);
 	if (bp->b_error) {
-		int	error = bp->b_error;
+		error = bp->b_error;
 		xfs_buf_relse(bp);
 		return error;
 	}
@@ -957,11 +958,12 @@ xfs_buf_read_uncached(
 	return 0;
 }
 
-xfs_buf_t *
+int
 xfs_buf_get_uncached(
 	struct xfs_buftarg	*target,
 	size_t			numblks,
-	int			flags)
+	int			flags,
+	struct xfs_buf		**bpp)
 {
 	unsigned long		page_count;
 	int			error, i;
@@ -980,8 +982,10 @@ xfs_buf_get_uncached(
 
 	for (i = 0; i < page_count; i++) {
 		bp->b_pages[i] = alloc_page(xb_to_gfp(flags));
-		if (!bp->b_pages[i])
+		if (!bp->b_pages[i]) {
+			error = -ENOMEM;
 			goto fail_free_mem;
+		}
 	}
 	bp->b_flags |= _XBF_PAGES;
 
@@ -993,7 +997,8 @@ xfs_buf_get_uncached(
 	}
 
 	trace_xfs_buf_get_uncached(bp, _RET_IP_);
-	return bp;
+	*bpp = bp;
+	return 0;
 
  fail_free_mem:
 	while (--i >= 0)
@@ -1003,7 +1008,7 @@ xfs_buf_get_uncached(
 	xfs_buf_free_maps(bp);
 	kmem_cache_free(xfs_buf_zone, bp);
  fail:
-	return NULL;
+	return error;
 }
 
 /*
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 267b35daf662..e0e8b0769758 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -221,8 +221,8 @@ xfs_buf_readahead(
 	return xfs_buf_readahead_map(target, &map, 1, ops);
 }
 
-struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
-				int flags);
+int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks, int flags,
+		struct xfs_buf **bpp);
 int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
 			  size_t numblks, int flags, struct xfs_buf **bpp,
 			  const struct xfs_buf_ops *ops);