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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Adi Suresh <adisuresh@google.com>,
        Catherine Sullivan <csully@google.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.3 50/95] gve: fix dma sync bug where not all pages synced
Date:   Wed, 27 Nov 2019 21:32:07 +0100
Message-Id: <20191127202916.306351502@linuxfoundation.org>
In-Reply-To: <20191127202845.651587549@linuxfoundation.org>
References: <20191127202845.651587549@linuxfoundation.org>
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From: Adi Suresh <adisuresh@google.com>

commit db96c2cb4870173ea9b08df130f1d1cc9b5dd53d upstream.

The previous commit had a bug where the last page in the memory range
could not be synced. This change fixes the behavior so that all the
required pages are synced.

Fixes: 9cfeeb576d49 ("gve: Fixes DMA synchronization")
Signed-off-by: Adi Suresh <adisuresh@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/ethernet/google/gve/gve_tx.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/drivers/net/ethernet/google/gve/gve_tx.c
+++ b/drivers/net/ethernet/google/gve/gve_tx.c
@@ -393,12 +393,13 @@ static void gve_tx_fill_seg_desc(union g
 static void gve_dma_sync_for_device(struct device *dev, dma_addr_t *page_buses,
 				    u64 iov_offset, u64 iov_len)
 {
+	u64 last_page = (iov_offset + iov_len - 1) / PAGE_SIZE;
+	u64 first_page = iov_offset / PAGE_SIZE;
 	dma_addr_t dma;
-	u64 addr;
+	u64 page;
 
-	for (addr = iov_offset; addr < iov_offset + iov_len;
-	     addr += PAGE_SIZE) {
-		dma = page_buses[addr / PAGE_SIZE];
+	for (page = first_page; page <= last_page; page++) {
+		dma = page_buses[page];
 		dma_sync_single_for_device(dev, dma, PAGE_SIZE, DMA_TO_DEVICE);
 	}
 }