dm crypt: avoid unnecessary wait when splitting bio
authorMilan Broz <mbroz@redhat.com>
Fri, 10 Oct 2008 12:37:08 +0000 (13:37 +0100)
committerAlasdair G Kergon <agk@redhat.com>
Fri, 10 Oct 2008 12:37:08 +0000 (13:37 +0100)
commit933f01d43326fb12a978a8e0bb062c28a2de4d5a
tree89f25c15fb98d90ee7377437482e444a8ac6a106
parentc8081618a9f832fdf7ca81eb087f9f61f2bf07d5
dm crypt: avoid unnecessary wait when splitting bio

Don't wait between submitting crypt requests for a bio unless
we are short of memory.

There are two situations when we must split an encrypted bio:
  1) there are no free pages;
  2) the new bio would violate underlying device restrictions
(e.g. max hw segments).

In case (2) we do not need to wait.

Add output variable to crypt_alloc_buffer() to distinguish between
these cases.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
drivers/md/dm-crypt.c