dm crypt: fix async inc_pending

The pending reference count must be incremented *before* the async work is
queued to another thread, not after.  Otherwise there's a race if the
work completes and decrements the reference count before it gets incremented.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Milan Broz 2008-10-10 13:37:07 +01:00 коммит произвёл Alasdair G Kergon
Родитель 6c031f41db
Коммит 4e59409891
1 изменённых файлов: 2 добавлений и 3 удалений

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@ -719,16 +719,15 @@ static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
remaining -= clone->bi_size;
crypt_inc_pending(io);
r = crypt_convert(cc, &io->ctx);
if (atomic_dec_and_test(&io->ctx.pending)) {
/* processed, no running async crypto */
crypt_inc_pending(io);
kcryptd_crypt_write_io_submit(io, r, 0);
if (unlikely(r < 0))
break;
} else
crypt_inc_pending(io);
}
/* out of memory -> run queues */
if (unlikely(remaining)) {