[PATCH rfc 9/9] fs: aio: add explicit check for large folio in aio_migrate_folio()

From: Kefeng Wang <wangkefeng.wang@huawei.com>
To: Andrew Morton <akpm@linux-foundation.org>, <linux-mm@kvack.org>
Cc: Tony Luck <tony.luck@intel.com>,
	Naoya Horiguchi <naoya.horiguchi@nec.com>,
	Miaohe Lin <linmiaohe@huawei.com>,
	Matthew Wilcox <willy@infradead.org>,
	David Hildenbrand <david@redhat.com>,
	Muchun Song <muchun.song@linux.dev>,
	Benjamin LaHaise <bcrl@kvack.org>, <jglisse@redhat.com>,
	<linux-aio@kvack.org>, <linux-fsdevel@vger.kernel.org>,
	Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: [PATCH rfc 9/9] fs: aio: add explicit check for large folio in aio_migrate_folio()
Date: Mon, 29 Jan 2024 15:09:34 +0800	[thread overview]
Message-ID: <20240129070934.3717659-10-wangkefeng.wang@huawei.com> (raw)
In-Reply-To: <20240129070934.3717659-1-wangkefeng.wang@huawei.com>

Since large folio copy could spend lots of time and it is involved with
a cond_resched(), the aio couldn't support migrate large folio as it takes
a spin lock when folio copy, add explicit check for large folio and return
err directly.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 fs/aio.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/aio.c b/fs/aio.c
index 631e83eee5a1..372f22b85b11 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -411,6 +411,10 @@ static int aio_migrate_folio(struct address_space *mapping, struct folio *dst,
 	pgoff_t idx;
 	int rc = 0;
 
+	/* Large folio aren't supported */
+	if (folio_test_large(src))
+		return -EINVAL;
+
 	/* mapping->i_private_lock here protects against the kioctx teardown.  */
 	spin_lock(&mapping->i_private_lock);
 	ctx = mapping->i_private_data;
-- 
2.27.0

