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authorRalph Campbell <rcampbell@nvidia.com>2018-04-10 16:28:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-11 10:28:30 -0700
commite1401513c6b5efec59678a4d4e9f90957684b7e3 (patch)
tree3c3d5bd62643829a0f37155780161acbe5c290ed /include
parentb28b08de436a638c82d0cf3dcdbdbad055baf1fc (diff)
downloadlinux-e1401513c6b5efec59678a4d4e9f90957684b7e3.tar.gz
mm/hmm: HMM should have a callback before MM is destroyed
hmm_mirror_register() registers a callback for when the CPU pagetable is
modified.  Normally, the device driver will call hmm_mirror_unregister()
when the process using the device is finished.  However, if the process
exits uncleanly, the struct_mm can be destroyed with no warning to the
device driver.

Link: http://lkml.kernel.org/r/20180323005527.758-4-jglisse@redhat.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/hmm.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index 36dd21fe5caf..fa7b51f65905 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -218,6 +218,16 @@ enum hmm_update_type {
  * @update: callback to update range on a device
  */
 struct hmm_mirror_ops {
+	/* release() - release hmm_mirror
+	 *
+	 * @mirror: pointer to struct hmm_mirror
+	 *
+	 * This is called when the mm_struct is being released.
+	 * The callback should make sure no references to the mirror occur
+	 * after the callback returns.
+	 */
+	void (*release)(struct hmm_mirror *mirror);
+
 	/* sync_cpu_device_pagetables() - synchronize page tables
 	 *
 	 * @mirror: pointer to struct hmm_mirror