xen/gntdev: Fix circular locking dependency

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apply_to_page_range will acquire PTE lock while priv->lock is held,
and mn_invl_range_start tries to acquire priv->lock with PTE already
held.  Fix by not holding priv->lock during the entire map operation.
This is safe because map->vma is set nonzero while the lock is held,
which will cause subsequent maps to fail and will cause the unmap
ioctl (and other users of gntdev_del_map) to return -EBUSY until the
area is unmapped. It is similarly impossible for gntdev_vma_close to
be called while the vma is still being created.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

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Daniel De Graaf 2011-01-07 11:51:47 +00:00 • committed by Konrad Rzeszutek Wilk

parent ba5d101229

commit f0a70c882e

1 changed files with 7 additions and 2 deletions

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drivers/xen/gntdev.c

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