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authorLinus Torvalds <torvalds@linux-foundation.org>2016-01-21 18:19:38 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-21 18:19:38 -0800
commit641203549a21ba6a701aecd05c3dfc969ec670cc (patch)
tree5e3d177c380ed811b5bf37e0bf9b8098416a9bc6 /include/xen
parent404a47410c26a115123885977053e9a1a4460929 (diff)
parente93d12ae3be91d18b2a46deebb90a3f516db3d3c (diff)
downloadtalos-obmc-linux-641203549a21ba6a701aecd05c3dfc969ec670cc.tar.gz
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Merge branch 'for-4.5/drivers' of git://git.kernel.dk/linux-block
Pull block driver updates from Jens Axboe: "This is the block driver pull request for 4.5, with the exception of NVMe, which is in a separate branch and will be posted after this one. This pull request contains: - A set of bcache stability fixes, which have been acked by Kent. These have been used and tested for more than a year by the community, so it's about time that they got in. - A set of drbd updates from the drbd team (Andreas, Lars, Philipp) and Markus Elfring, Oleg Drokin. - A set of fixes for xen blkback/front from the usual suspects, (Bob, Konrad) as well as community based fixes from Kiri, Julien, and Peng. - A 2038 time fix for sx8 from Shraddha, with a fix from me. - A small mtip32xx cleanup from Zhu Yanjun. - A null_blk division fix from Arnd" * 'for-4.5/drivers' of git://git.kernel.dk/linux-block: (71 commits) null_blk: use sector_div instead of do_div mtip32xx: restrict variables visible in current code module xen/blkfront: Fix crash if backend doesn't follow the right states. xen/blkback: Fix two memory leaks. xen/blkback: make st_ statistics per ring xen/blkfront: Handle non-indirect grant with 64KB pages xen-blkfront: Introduce blkif_ring_get_request xen-blkback: clear PF_NOFREEZE for xen_blkif_schedule() xen/blkback: Free resources if connect_ring failed. xen/blocks: Return -EXX instead of -1 xen/blkback: make pool of persistent grants and free pages per-queue xen/blkback: get the number of hardware queues/rings from blkfront xen/blkback: pseudo support for multi hardware queues/rings xen/blkback: separate ring information out of struct xen_blkif xen/blkfront: correct setting for xen_blkif_max_ring_order xen/blkfront: make persistent grants pool per-queue xen/blkfront: Remove duplicate setting of ->xbdev. xen/blkfront: Cleanup of comments, fix unaligned variables, and syntax errors. xen/blkfront: negotiate number of queues/rings to be used with backend xen/blkfront: split per device io_lock ...
Diffstat (limited to 'include/xen')
-rw-r--r--include/xen/interface/io/blkif.h48
1 files changed, 48 insertions, 0 deletions
diff --git a/include/xen/interface/io/blkif.h b/include/xen/interface/io/blkif.h
index c33e1c489eb2..8b8cfadf7833 100644
--- a/include/xen/interface/io/blkif.h
+++ b/include/xen/interface/io/blkif.h
@@ -28,6 +28,54 @@ typedef uint16_t blkif_vdev_t;
typedef uint64_t blkif_sector_t;
/*
+ * Multiple hardware queues/rings:
+ * If supported, the backend will write the key "multi-queue-max-queues" to
+ * the directory for that vbd, and set its value to the maximum supported
+ * number of queues.
+ * Frontends that are aware of this feature and wish to use it can write the
+ * key "multi-queue-num-queues" with the number they wish to use, which must be
+ * greater than zero, and no more than the value reported by the backend in
+ * "multi-queue-max-queues".
+ *
+ * For frontends requesting just one queue, the usual event-channel and
+ * ring-ref keys are written as before, simplifying the backend processing
+ * to avoid distinguishing between a frontend that doesn't understand the
+ * multi-queue feature, and one that does, but requested only one queue.
+ *
+ * Frontends requesting two or more queues must not write the toplevel
+ * event-channel and ring-ref keys, instead writing those keys under sub-keys
+ * having the name "queue-N" where N is the integer ID of the queue/ring for
+ * which those keys belong. Queues are indexed from zero.
+ * For example, a frontend with two queues must write the following set of
+ * queue-related keys:
+ *
+ * /local/domain/1/device/vbd/0/multi-queue-num-queues = "2"
+ * /local/domain/1/device/vbd/0/queue-0 = ""
+ * /local/domain/1/device/vbd/0/queue-0/ring-ref = "<ring-ref#0>"
+ * /local/domain/1/device/vbd/0/queue-0/event-channel = "<evtchn#0>"
+ * /local/domain/1/device/vbd/0/queue-1 = ""
+ * /local/domain/1/device/vbd/0/queue-1/ring-ref = "<ring-ref#1>"
+ * /local/domain/1/device/vbd/0/queue-1/event-channel = "<evtchn#1>"
+ *
+ * It is also possible to use multiple queues/rings together with
+ * feature multi-page ring buffer.
+ * For example, a frontend requests two queues/rings and the size of each ring
+ * buffer is two pages must write the following set of related keys:
+ *
+ * /local/domain/1/device/vbd/0/multi-queue-num-queues = "2"
+ * /local/domain/1/device/vbd/0/ring-page-order = "1"
+ * /local/domain/1/device/vbd/0/queue-0 = ""
+ * /local/domain/1/device/vbd/0/queue-0/ring-ref0 = "<ring-ref#0>"
+ * /local/domain/1/device/vbd/0/queue-0/ring-ref1 = "<ring-ref#1>"
+ * /local/domain/1/device/vbd/0/queue-0/event-channel = "<evtchn#0>"
+ * /local/domain/1/device/vbd/0/queue-1 = ""
+ * /local/domain/1/device/vbd/0/queue-1/ring-ref0 = "<ring-ref#2>"
+ * /local/domain/1/device/vbd/0/queue-1/ring-ref1 = "<ring-ref#3>"
+ * /local/domain/1/device/vbd/0/queue-1/event-channel = "<evtchn#1>"
+ *
+ */
+
+/*
* REQUEST CODES.
*/
#define BLKIF_OP_READ 0
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