linux-kernel - [PATCH 20/29] xfs: distinguish error type of memory allocation failure for nowait case

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Message-Id: <20230825135431.1317785-21-hao.xu@linux.dev>
Date:   Fri, 25 Aug 2023 21:54:22 +0800
From:   Hao Xu <hao.xu@...ux.dev>
To:     io-uring@...r.kernel.org, Jens Axboe <axboe@...nel.dk>
Cc:     Dominique Martinet <asmadeus@...ewreck.org>,
        Pavel Begunkov <asml.silence@...il.com>,
        Christian Brauner <brauner@...nel.org>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Stefan Roesch <shr@...com>, Clay Harris <bugs@...ycon.org>,
        Dave Chinner <david@...morbit.com>,
        "Darrick J . Wong" <djwong@...nel.org>,
        linux-fsdevel@...r.kernel.org, linux-xfs@...r.kernel.org,
        linux-ext4@...r.kernel.org, linux-cachefs@...hat.com,
        ecryptfs@...r.kernel.org, linux-nfs@...r.kernel.org,
        linux-unionfs@...r.kernel.org, bpf@...r.kernel.org,
        netdev@...r.kernel.org, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
        linux-btrfs@...r.kernel.org, codalist@...a.cs.cmu.edu,
        linux-f2fs-devel@...ts.sourceforge.net, cluster-devel@...hat.com,
        linux-mm@...ck.org, linux-nilfs@...r.kernel.org,
        devel@...ts.orangefs.org, linux-cifs@...r.kernel.org,
        samba-technical@...ts.samba.org, linux-mtd@...ts.infradead.org,
        Wanpeng Li <wanpengli@...cent.com>
Subject: [PATCH 20/29] xfs: distinguish error type of memory allocation failure for nowait case

From: Hao Xu <howeyxu@...cent.com>

Previously, if we fail to get the memory we need, -ENOMEM is returned.
It can be -EAGAIN now since we support nowait now. Return the latter
when it is the case. Involved functions are:  _xfs_buf_map_pages(),
xfs_buf_get_maps(), xfs_buf_alloc_kmem() and xfs_buf_alloc_pages().

Signed-off-by: Hao Xu <howeyxu@...cent.com>
---
 fs/xfs/xfs_buf.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 8b800ce28996..a6e6e64ff940 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -192,7 +192,7 @@ xfs_buf_get_maps(
 	bp->b_maps = kmem_zalloc(map_count * sizeof(struct xfs_buf_map),
 				KM_NOFS);
 	if (!bp->b_maps)
-		return -ENOMEM;
+		return bp->b_flags & XBF_NOWAIT ? -EAGAIN : -ENOMEM;
 	return 0;
 }
 
@@ -339,7 +339,7 @@ xfs_buf_alloc_kmem(
 
 	bp->b_addr = kmem_alloc(size, kmflag_mask);
 	if (!bp->b_addr)
-		return -ENOMEM;
+		return flags & XBF_NOWAIT ? -EAGAIN : -ENOMEM;
 
 	if (((unsigned long)(bp->b_addr + size - 1) & PAGE_MASK) !=
 	    ((unsigned long)bp->b_addr & PAGE_MASK)) {
@@ -363,6 +363,7 @@ xfs_buf_alloc_pages(
 {
 	gfp_t		gfp_mask = __GFP_NOWARN;
 	long		filled = 0;
+	bool		nowait = flags & XBF_NOWAIT;
 
 	if (flags & XBF_READ_AHEAD)
 		gfp_mask |= __GFP_NORETRY;
@@ -377,7 +378,7 @@ xfs_buf_alloc_pages(
 		bp->b_pages = kzalloc(sizeof(struct page *) * bp->b_page_count,
 					gfp_mask);
 		if (!bp->b_pages)
-			return -ENOMEM;
+			return nowait ? -EAGAIN : -ENOMEM;
 	}
 	bp->b_flags |= _XBF_PAGES;
 
@@ -451,7 +452,7 @@ _xfs_buf_map_pages(
 		memalloc_nofs_restore(nofs_flag);
 
 		if (!bp->b_addr)
-			return -ENOMEM;
+			return flags & XBF_NOWAIT ? -EAGAIN : -ENOMEM;
 	}
 
 	return 0;
-- 
2.25.1