dm io: delay dec_count
authorHeinz Mauelshagen <hjm@redhat.com>
Wed, 9 May 2007 09:33:00 +0000 (02:33 -0700)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Wed, 9 May 2007 19:30:47 +0000 (12:30 -0700)
Delay decrementing the 'struct io' reference count until after the bio has
been freed so that a bio destructor function may reference it.  Required by a
later patch.

Signed-off-by: Heinz Mauelshagen <hjm@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: Milan Broz <mbroz@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/md/dm-io.c

index 8bdc8a87b249c4b9a0b46ab0e22308e30ed7c1d6..4d19c45158b45a695c31cc31415a15a8fb02c30e 100644 (file)
@@ -126,7 +126,8 @@ static void dec_count(struct io *io, unsigned int region, int error)
 
 static int endio(struct bio *bio, unsigned int done, int error)
 {
-       struct io *io = (struct io *) bio->bi_private;
+       struct io *io;
+       unsigned region;
 
        /* keep going until we've finished */
        if (bio->bi_size)
@@ -135,10 +136,17 @@ static int endio(struct bio *bio, unsigned int done, int error)
        if (error && bio_data_dir(bio) == READ)
                zero_fill_bio(bio);
 
-       dec_count(io, bio_get_region(bio), error);
+       /*
+        * The bio destructor in bio_put() may use the io object.
+        */
+       io = bio->bi_private;
+       region = bio_get_region(bio);
+
        bio->bi_max_vecs++;
        bio_put(bio);
 
+       dec_count(io, region, error);
+
        return 0;
 }