Commit Graph

31 Commits

Author SHA1 Message Date
Dan Carpenter 9b83c77121 xen/blkback: potential null dereference in error handling
blkbk->pending_pages can be NULL here so I added a check for it.

Signed-off-by: Dan Carpenter <error27@gmail.com>
[v1: Redid the loop a bit]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-06-01 09:28:21 -04:00
Laszlo Ersek 6464920a6e xen/blkback: don't call vbd_size() if bd_disk is NULL
...because vbd_size() dereferences bd_disk if bd_part is NULL.

Signed-off-by: Laszlo Ersek<lersek@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-06-01 09:28:20 -04:00
Jan Beulich 8ab521506c xen/blkback: don't fail empty barrier requests
The sector number on empty barrier requests may (will?) be -1, which,
given that it's being treated as unsigned 64-bit quantity, will almost
always exceed the actual (virtual) disk's size.

Inspired by Konrad's "When writting barriers set the sector number to
zero...".

While at it also add overflow checking to the math in vbd_translate().

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-18 11:28:16 -04:00
Laszlo Ersek 496b318eb6 xen/blkback: fix xenbus_transaction_start() hang caused by double xenbus_transaction_end()
vbd_resize() up_read()'s xs_state.suspend_mutex twice in a row via double
xenbus_transaction_end() calls. The next down_read() in
xenbus_transaction_start() (at eg. the next resize attempt) hangs.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=618317

Acked-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-13 09:45:40 -04:00
Konrad Rzeszutek Wilk 5185432277 xen/blkback: Align the tabs on the structure.
The recent changes caused this field of the structure to be offset a bit.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 18:02:28 -04:00
Konrad Rzeszutek Wilk cca537af7d xen/blkback: if log_stats is enabled print out the data.
And not depend on the driver being built with -DDEBUG flag.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 17:55:54 -04:00
Konrad Rzeszutek Wilk 5a577e3872 xen/blkback: Add the prefix XEN in the common.h.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 17:55:53 -04:00
Konrad Rzeszutek Wilk 3d814731ba xen/blkback: Prefix 'vbd' with 'xen' in structs and functions.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 17:55:52 -04:00
Konrad Rzeszutek Wilk 30fd150202 xen/blkback: Change structure name blkif_st to xen_blkif.
No need for that '_st' and xen_blkif is more apt.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 17:55:51 -04:00
Konrad Rzeszutek Wilk 325a648604 xen/blkback: Remove the unused typedefs.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 17:55:50 -04:00
Konrad Rzeszutek Wilk 452a6b2bb6 xen/blkback: Move include/xen/blkif.h into drivers/block/xen-blkback/common.h
Not point of the blkif.h file. It is not used by the frontend.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 17:55:49 -04:00
Konrad Rzeszutek Wilk b0f801273f xen/blkback: Fixing some more of the cleanpatch.pl warnings.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 17:55:48 -04:00
Konrad Rzeszutek Wilk 03e0edf946 xen/blkback: Checkpatch.pl recommend against multiple assigments.
CHECK: multiple assignments should be avoided

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 17:55:47 -04:00
Konrad Rzeszutek Wilk b9fc02968c xen/blkback: Fix spelling mistakes.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 16:43:21 -04:00
Konrad Rzeszutek Wilk 68c88dd7d3 xen/blkback: Move blkif_get_x86_[32|64]_req to common.h in block/xen-blkback dir.
From the blkif.h header, which was exposed to the frontend.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 16:43:20 -04:00
Konrad Rzeszutek Wilk 72468bfcb8 xen/blkback: Removing the debug_lvl option.
It is not really used for anything.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 16:43:20 -04:00
Konrad Rzeszutek Wilk 22b20f2dff xen/blkback: Use the DRV_PFX in the pr_.. macros.
To make it easier to read.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 16:43:12 -04:00
Konrad Rzeszutek Wilk 1afbd730a3 xen/blkback: Make the DPRINTK uniform.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 16:42:51 -04:00
Konrad Rzeszutek Wilk ebe8190659 xen/blkback: Change printk/DPRINTK to pr_.. type variant.
And also make them uniform and prefix the message with 'xen-blkback'.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-12 16:42:31 -04:00
Konrad Rzeszutek Wilk 01f37f2d53 xen/blkback: Fixed up comments and converted spaces to tabs.
Suggested-by: Ian Campbell <Ian.Campbell@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-11 15:57:09 -04:00
Konrad Rzeszutek Wilk 3d68b39926 xen/blkback: Fix up some of the comments.
They had the wrong data or were in the wrong spot.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-05 13:43:26 -04:00
Konrad Rzeszutek Wilk fc53bf757e xen/blkback: Squash the checking for operation into dispatch_rw_block_io
We do a check for the operations right before calling dispatch_rw_block_io.
And then we do the same check in dispatch_rw_block_io. This patch
squashes those checks into the 'dispatch_rw_block_io' function.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-05 13:43:25 -04:00
Konrad Rzeszutek Wilk 24f567f952 xen/blkback: Add support for BLKIF_OP_FLUSH_DISKCACHE and drop BLKIF_OP_WRITE_BARRIER.
We drop the support for 'feature-barrier' and add in the support
for the 'feature-flush-cache' if the real backend storage supports
flushing.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-05-05 13:43:24 -04:00
Konrad Rzeszutek Wilk a19be5f0f0 Revert "xen/blkback: Move the plugging/unplugging to a higher level."
This reverts commit 97961ef46b b/c
we lose about 15% performance if we do the unplugging and the
end of the reading the ring buffer.
2011-04-27 12:40:11 -04:00
Konrad Rzeszutek Wilk 013c3ca184 xen/blkback: Stick REQ_SYNC on WRITEs to deal with CFQ I/O scheduler.
If one runs a simple fio request with random read/write with a
20%/80% ratio, the numbers are incredibly bad when using the CFQ scheduler.

IOmeter       |       |      |          |
64K, randrw   |  NOOP | CFQ  | deadline |
randrwmix=80  |       |      |          |
--------------+-------+------+----------+
blkback       |103/27 |32/10 | 102/27   |
--------------+-------+------+----------+
QEMU qdisk    |103/27 |102/27| 102/27   |

The problem as explained by Vivek Goyal was:

".. that difference is that sync vs async requests. In the case of
a kernel thread submitting IO, [..] all the WRITES might be being
considered as async and will go in a different queue. If you mix those
with some READS, they are always sync and will go in differnet queue.
In presence of sync queue, CFQ will idle and choke up WRITES in
an attempt to improve latencies of READs.

In case of AIO [note: this is what QEMU qdisk is doing] , [..]
it is direct IO and both READS and WRITES will be considered SYNC
and will go in a single queue and no choking of WRITES will take place."

The solution is quite simple, tack on REQ_SYNC (which is
what the WRITE_ODIRECT macro points to) and the numbers go
back up.

Suggested-by: Vivek Goyal <vgoyal@redhat.com
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-04-26 16:24:18 -04:00
Konrad Rzeszutek Wilk 97961ef46b xen/blkback: Move the plugging/unplugging to a higher level.
We used to the plug/unplug on the submit_bio. But that means
if within a stream of WRITE, WRITE, WRITE,...,WRITE we have
one READ, it could stall the pipeline (as the 'submio_bio'
could trigger the unplug_fnc to be called and stall/sync
when doing the READ). Instead we want to move the unplugging
when the whole (or as a much as possible) ring buffer has been
processed. This also eliminates us doing plug/unplug for
each request.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-04-26 13:01:32 -04:00
Konrad Rzeszutek Wilk 8b6bf747d7 xen/blkback: Prefix exposed functions with xen_
And also shorten the name if it has blkback to blkbk.

This results in the symbol table (if compiled in the kernel)
to be much shorter, prettier,  and also easier to search for.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-04-20 11:58:03 -04:00
Konrad Rzeszutek Wilk 42c7841d17 xen-blkback: Inline some of the functions that were moved from vbd/interface.c
Shuffling code around.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-04-20 11:58:02 -04:00
Konrad Rzeszutek Wilk 6cd0388cd6 xen-blkback: Remove from the copyright notice the address.
There is no need for it, as the address is updated constatly
in the root of the Linux kernel.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-04-20 11:58:01 -04:00
Konrad Rzeszutek Wilk ee9ff8537e xen/blkback: Squash vbd.c,interface.c in blkback.c and xenbus.c respectivly.
Daniel Stodden suggested to eliminate vbd.c and interface.c, inlining the
critical bits where they belong, respectively.

Leaving only blkback.c for the data- and xenbus.c for the control path.

Suggested-by:  Daniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-04-20 11:57:59 -04:00
Konrad Rzeszutek Wilk dfc07b13dc xen/blkback: Move it from drivers/xen to drivers/block
.. and modify the Makefile and Kconfig files appropriately.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-04-18 14:30:26 -04:00