| From | Luis Henriques <> | Subject | [PATCH 3.16.y-ckt 228/254] sunvdc: limit each sg segment to a page | Date | Tue, 25 Nov 2014 10:39:38 +0000 |
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3.16.7-ckt2 -stable review patch. If anyone has any objections, please let me know.
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From: Dwight Engen <dwight.engen@oracle.com>
commit 5eed69ffd248c9f68f56c710caf07db134aef28b upstream.
ldc_map_sg() could fail its check that the number of pages referred to by the sg scatterlist was <= the number of cookies.
This fixes the issue by doing a similar thing to the xen-blkfront driver, ensuring that the scatterlist will only ever contain a segment count <= port->ring_cookies, and each segment will be page aligned, and <= page size. This ensures that the scatterlist is always mappable.
Orabug: 19347817 OraBZ: 15945
Signed-off-by: Dwight Engen <dwight.engen@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/block/sunvdc.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c index 1616ad091a5e..1a9360da1f54 100644 --- a/drivers/block/sunvdc.c +++ b/drivers/block/sunvdc.c @@ -747,6 +747,10 @@ static int probe_disk(struct vdc_port *port) port->disk = g; + /* Each segment in a request is up to an aligned page in size. */ + blk_queue_segment_boundary(q, PAGE_SIZE - 1); + blk_queue_max_segment_size(q, PAGE_SIZE); + blk_queue_max_segments(q, port->ring_cookies); blk_queue_max_hw_sectors(q, port->max_xfer_size); g->major = vdc_major; -- 2.1.0
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