linux-kernel - [PATCH v4 3/3] drbd: code cleanup by using sendpage_ok() to check page for kernel

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Message-Id: <20200815124254.115076-3-colyli@suse.de>
Date:   Sat, 15 Aug 2020 20:42:54 +0800
From:   colyli@...e.de
To:     linux-block@...r.kernel.org, linux-nvme@...ts.infradead.org
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org, Coly Li <colyli@...e.de>,
        Philipp Reisner <philipp.reisner@...bit.com>,
        Sagi Grimberg <sagi@...mberg.me>
Subject: [PATCH v4 3/3] drbd: code cleanup by using sendpage_ok() to check page for kernel_sendpage()

From: Coly Li <colyli@...e.de>

In _drbd_send_page() a page is checked by following code before sending
it by kernel_sendpage(),
        (page_count(page) < 1) || PageSlab(page)
If the check is true, this page won't be send by kernel_sendpage() and
handled by sock_no_sendpage().

This kind of check is exactly what macro sendpage_ok() does, which is
introduced into include/linux/net.h to solve a similar send page issue
in nvme-tcp code.

This patch uses macro sendpage_ok() to replace the open coded checks to
page type and refcount in _drbd_send_page(), as a code cleanup.

Signed-off-by: Coly Li <colyli@...e.de>
Cc: Philipp Reisner <philipp.reisner@...bit.com>
Cc: Sagi Grimberg <sagi@...mberg.me>
---
Changelog:
v3, introduce a more common sendpage_ok()
v2, fix typo in patch subject
v1, the initial version.
 drivers/block/drbd/drbd_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index cb687ccdbd96..55dc0c91781e 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1553,7 +1553,7 @@ static int _drbd_send_page(struct drbd_peer_device *peer_device, struct page *pa
 	 * put_page(); and would cause either a VM_BUG directly, or
 	 * __page_cache_release a page that would actually still be referenced
 	 * by someone, leading to some obscure delayed Oops somewhere else. */
-	if (drbd_disable_sendpage || (page_count(page) < 1) || PageSlab(page))
+	if (drbd_disable_sendpage || !sendpage_ok(page))
 		return _drbd_no_send_page(peer_device, page, offset, size, msg_flags);
 
 	msg_flags |= MSG_NOSIGNAL;
-- 
2.26.2