From 5ec140e600b7d6624c657f008833f0e71bd5ef48 Mon Sep 17 00:00:00 2001
From: Vasily Averin <vvs@sw.ru>
Date: Wed, 31 Oct 2007 08:33:24 +0100
Subject: [PATCH] dm: bounce_pfn limit added
Device mapper uses its own bounce_pfn that may differ from one on underlying
device. In that way dm can build incorrect requests that contain sg elements
greater than underlying device is able to handle.
This is the cause of slab corruption in i2o layer, occurred on i386 arch when
very long direct IO requests are addressed to dm-over-i2o device.
Signed-off-by: Vasily Averin <vvs@sw.ru>
Cc: <stable@kernel.org>
Cc: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
drivers/md/dm-table.c | 7 +++++++
include/linux/device-mapper.h | 1 +
2 files changed, 8 insertions(+)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 8939e61050884..5a7eb650181e1 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -102,6 +102,8 @@ static void combine_restrictions_low(struct io_restrictions *lhs,
lhs->seg_boundary_mask =
min_not_zero(lhs->seg_boundary_mask, rhs->seg_boundary_mask);
+ lhs->bounce_pfn = min_not_zero(lhs->bounce_pfn, rhs->bounce_pfn);
+
lhs->no_cluster |= rhs->no_cluster;
}
@@ -566,6 +568,8 @@ void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
min_not_zero(rs->seg_boundary_mask,
q->seg_boundary_mask);
+ rs->bounce_pfn = min_not_zero(rs->bounce_pfn, q->bounce_pfn);
+
rs->no_cluster |= !test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
}
EXPORT_SYMBOL_GPL(dm_set_device_limits);
@@ -707,6 +711,8 @@ static void check_for_valid_limits(struct io_restrictions *rs)
rs->max_segment_size = MAX_SEGMENT_SIZE;
if (!rs->seg_boundary_mask)
rs->seg_boundary_mask = -1;
+ if (!rs->bounce_pfn)
+ rs->bounce_pfn = -1;
}
int dm_table_add_target(struct dm_table *t, const char *type,
@@ -891,6 +897,7 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q)
q->hardsect_size = t->limits.hardsect_size;
q->max_segment_size = t->limits.max_segment_size;
q->seg_boundary_mask = t->limits.seg_boundary_mask;
+ q->bounce_pfn = t->limits.bounce_pfn;
if (t->limits.no_cluster)
q->queue_flags &= ~(1 << QUEUE_FLAG_CLUSTER);
else
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 37c66d1254b53..b8b7c51389fe0 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -116,6 +116,7 @@ struct io_restrictions {
unsigned short hardsect_size;
unsigned int max_segment_size;
unsigned long seg_boundary_mask;
+ unsigned long bounce_pfn;
unsigned char no_cluster; /* inverted so that 0 is default */
};
--
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