[PATCH v2 6/6] dax: bdev_direct_access() may sleep

From: Matthew Wilcox
Date: Fri Jul 03 2015 - 10:41:50 EST


The brd driver is the only in-tree driver that may sleep currently.
After some discussion on linux-fsdevel, we decided that any driver
may choose to sleep in its ->direct_access method. To ensure that all
callers of bdev_direct_access() are prepared for this, add a call
to might_sleep().

Signed-off-by: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
---
fs/block_dev.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 0bb2993..1982437 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -446,6 +446,12 @@ long bdev_direct_access(struct block_device *bdev, sector_t sector,
long avail;
const struct block_device_operations *ops = bdev->bd_disk->fops;

+ /*
+ * The device driver is allowed to sleep, in order to make the
+ * memory directly accessible.
+ */
+ might_sleep();
+
if (size < 0)
return size;
if (!ops->direct_access)
--
2.1.4

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