CA-136104: Adding better kernel version detection: http://lists.xen.org/archives/html/xen-devel/2013-12/msg01185.html

This prevents the failing on the call to io_setup with EINVAL. Tapdisk
currently detects kernel version for eventfd by looking for 'x.y.z',
which fails on the newer kernel versions.

Credit goes to James Harper from
http://lists.xen.org/archives/html/xen-devel/2013-12/msg01185.html

Signed-off-by: Antony Messerli <antony@mes.ser.li>
Reviewed-by: Thanos Makatos <thanos.makatos@citrix.com>

GitHub: closes #79 on xapi-project/blktap
CA-130898: use 32-bit protocol with guest if omitted

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Acked-by: Chandrika Srinivasan <chandrika.srinivasan@citrix.com>

(cherry picked from commit 6c86a979700ca4ff1e16fdcc44b3ff2ea4baddda)

GitHub: closes #84 on xapi-project/blktap
CA-145685: Fix size and offset for read requests

Signed-off-by: Flavien Quesnel <flavien.quesnel@citrix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@citrix.com>

GitHub: closes #133 on xapi-project/blktap
CA-140343: Fix 'Unknown error' in tapback

Signed-off-by: Siddharth Vinothkumar <siddharth.vinothkumar@citrix.com>
Reviewed-by: Chandrika Srinivasan <chandrika.srinivasan@citrix.com>

GitHub: closes #130 on xapi-project/blktap
CA-147671: Refactor block-aio.c before unit testing tdaio_queue_read

Signed-off-by: Flavien Quesnel <flavien.quesnel@citrix.com>
Reviewed-by: Chandrika Srinivasan <chandrika.srinivasan@citrix.com>
CA-147671: [UnitTest] Add unit tests for tdaio_queue_read

Signed-off-by: Flavien Quesnel <flavien.quesnel@citrix.com>
Reviewed-by: Chandrika Srinivasan <chandrika.srinivasan@citrix.com>
Merge branch 'CA-147671' into xs64bit

Signed-off-by: Flavien Quesnel <flavien.quesnel@citrix.com>
Revert "Merge branch 'CA-147671' into xs64bit"

This reverts commit e1d4b6a5b5e2990e37c30e6189eeffbc89fe729e, reversing
changes made to 8c43c80de28b6911b96822048de3cf27752bb553.

Commits 5b23740c and 0d146e6b are reverted because they break the build
and the merge doesn't have a "GitHub: closes ..." tag.

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
CA-147671: Refactor block-aio.c before unit testing tdaio_queue_read

Signed-off-by: Flavien Quesnel <flavien.quesnel@citrix.com>
Reviewed-by: Chandrika Srinivasan <chandrika.srinivasan@citrix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@citrix.com>
CA-147671: [UnitTest] Add unit tests for tdaio_queue_read

Signed-off-by: Flavien Quesnel <flavien.quesnel@citrix.com>
Reviewed-by: Chandrika Srinivasan <chandrika.srinivasan@citrix.com>
Merge branch 'CA-147671' into xs64bit

Signed-off-by: Flavien Quesnel <flavien.quesnel@citrix.com>

GitHub: closes #137 on xapi-project/blktap
Merge branch 'xs64bit'

Merge from product branch Creedence

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Documented how to test for O_DIRECT support

Signed-off-by: Cristian Klein <cristian.klein@cs.umu.se>
Acked-by: Thanos Makatos <thanos.makatos@citrix.com>

GitHub: closes #103 on xapi-project/blktap
CA-147743: option to build without gcopy

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
CA-147743: conditionally include xen/gntdev.h

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
CA-147743: include config.h in td-blkif.h

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>