This is a rewrite of the ramdisk block device driver.
The old one is really difficult because it effectively implements a block
device which serves data out of its own buffer cache. It relies on the dirty
bit being set, to pin its backing store in cache, however there are non
trivial paths which can clear the dirty bit (eg. try_to_free_buffers()),
which had recently lead to data corruption. And in general it is completely
wrong for a block device driver to do this.
The new one is more like a regular block device driver. It has no idea about
vm/vfs stuff. It's backing store is similar to the buffer cache (a simple
radix-tree of pages), but it doesn't know anything about page cache (the pages
in the radix tree are not pagecache pages).
There is one slight downside -- direct block device access and filesystem
metadata access goes through an extra copy and gets stored in RAM twice.
However, this downside is only slight, because the real buffercache of the
device is now reclaimable (because we're not playing crazy games with it), so
under memory intensive situations, footprint should effectively be the same --
maybe even a slight advantage to the new driver because it can also reclaim
buffer heads.
The fact that it now goes through all the regular vm/fs paths makes it
much more useful for testing, too.
text data bss dec hex filename
2837 849 384 4070 fe6 drivers/block/rd.o
3528 371 12 3911 f47 drivers/block/brd.o
Text is larger, but data and bss are smaller, making total size smaller.
A few other nice things about it:
- Similar structure and layout to the new loop device handlinag.
- Dynamic ramdisk creation.
- Runtime flexible buffer head size (because it is no longer part of the
ramdisk code).
- Boot / load time flexible ramdisk size, which could easily be extended
to a per-ramdisk runtime changeable size (eg. with an ioctl).
- Can use highmem for the backing store.
[akpm@linux-foundation.org: fix build]
[byron.bbradley@gmail.com: make rd_size non-static]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Byron Bradley <byron.bbradley@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit edfaa7c365
Driver core: convert block from raw kobjects to core devices
This moves the block devices to /sys/class/block. It will create a
flat list of all block devices, with the disks and partitions in one
directory. For compatibility /sys/block is created and contains symlinks
to the disks.
introduced a global disk_type variable in <linux/genhd.h>, causing the
following compile error on Atari:
drivers/block/ataflop.c:93: error: conflicting types for 'disk_type'
include/linux/genhd.h:21: error: previous declaration of 'disk_type' was here
Rename the local disk_type variable in drivers/block/ataflop.c to
atari_disk_type, to avoid the conflict.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use upper_32_bits(x) macro to handle shifts that may be >= the width of
the data type.
drivers/block/cciss.c: In function 'do_cciss_request':
drivers/block/cciss.c:2655: warning: right shift count >= width of type
drivers/block/cciss.c:2656: warning: right shift count >= width of type
drivers/block/cciss.c:2657: warning: right shift count >= width of type
drivers/block/cciss.c:2658: warning: right shift count >= width of type
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: <mike.miller@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This allows a flag to be set on loop devices so that when they are
closed for the last time, they'll self-destruct.
In general, so that we can automatically allocate loop devices (as with
losetup -f) and have them disappear when we're done with them.
In particular, right now, so that we can stop relying on the hackish
special-case in umount(8) which kills off loop devices which were set up by
'mount -oloop'. That means we can stop putting crap in /etc/mtab which
doesn't belong there, which means it can be a symlink to /proc/mounts, which
means yet another writable file on the root filesystem is eliminated and the
'stateless' folks get happier... and OLPC trac #356 can be closed.
The mount(8) side of that is at
http://marc.info/?l=util-linux-ng&m=119362955431694&w=2
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Cc: Bernardo Innocenti <bernie@codewiz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mainly, this involves two changes:
1) xilinx->xlnx (recognized standard is to use the stock ticker)
2) In order to have the device tree focus on describing what the
hardware is as exactly as possible, the compatible strings contain the
full IP name and IP version.
Signed-off-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Fix compile errors in the xilinxfb, xsysace and uartlite drivers used
by the Xilinx Virtex platform
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (25 commits)
virtio: balloon driver
virtio: Use PCI revision field to indicate virtio PCI ABI version
virtio: PCI device
virtio_blk: implement naming for vda-vdz,vdaa-vdzz,vdaaa-vdzzz
virtio_blk: Dont waste major numbers
virtio_blk: provide getgeo
virtio_net: parametrize the napi_weight for virtio receive queue.
virtio: free transmit skbs when notified, not on next xmit.
virtio: flush buffers on open
virtnet: remove double ether_setup
virtio: Allow virtio to be modular and used by modules
virtio: Use the sg_phys convenience function.
virtio: Put the virtio under the virtualization menu
virtio: handle interrupts after callbacks turned off
virtio: reset function
virtio: populate network rings in the probe routine, not open
virtio: Tweak virtio_net defines
virtio: Net header needs hdr_len
virtio: remove unused id field from struct virtio_blk_outhdr
virtio: clarify NO_NOTIFY flag usage
...
Am Freitag, 1. Februar 2008 schrieb Christian Borntraeger:
> Right. I will fix that with an additional patch.
This patch goes on top of the minor number patch. Please let me know if
you want a merged patch:
Currently virtio_blk creates the disk name combinging "vd" with 'a'++.
This will give strange names after vdz. I have implemented names up to
vdzzz - inspired by the sd.c code. That should be sufficient for now.
There is one driver in the kernel (driver/s390/block/dasd_genhd.c) that
implements names from dasda-dasdzzzz allowing even more disks. Maybe
a janitor can come up with a common implementation usable for all kind
of block device drivers.
I have tested this patch with 100 disks - seems to work.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Rusty,
currently virtio_blk uses one major number per device. While this works
quite well on most systems it is wasteful and will exhaust major numbers
on larger installations.
This patch allocates a major number on init and will use 16 minor numbers
for each disk. That will allow ~64k virtio_blk disks.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Rusty,
I currently try to make my guest boot from an virtio root device
without having an external kernel. Some of the tools that I tried
expect HDIO_GETGEO to work. The most interesting value is likely
the geo.start value to get the offset of a partition. This value
is filled by block/ioctl.c if fops->getgeo is set. This patch also
fills in some standard values for heads, sectors and cylinders.
Makes sense?
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This patch moves virtio under the virtualization menu and changes virtio
devices to not claim to only be for lguest.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
A reset function solves three problems:
1) It allows us to renegotiate features, eg. if we want to upgrade a
guest driver without rebooting the guest.
2) It gives us a clean way of shutting down virtqueues: after a reset,
we know that the buffers won't be used by the host, and
3) It helps the guest recover from messed-up drivers.
So we remove the ->shutdown hook, and the only way we now remove
feature bits is via reset.
We leave it to the driver to do the reset before it deletes queues:
the balloon driver, for example, needs to chat to the host in its
remove function.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
It seems that virtio_net wants to disable callbacks (interrupts) before
calling netif_rx_schedule(), so we can't use the return value to do so.
Rename "restart" to "cb_enable" and introduce "cb_disable" hook: callback
now returns void, rather than a boolean.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Previously we used a type/len pair within the config space, but this
seems overkill. We now simply define a structure which represents the
layout in the config space: the config space can now only be extended
at the end.
The main driver-visible changes:
1) We indicate what fields are present with an explicit feature bit.
2) Virtqueues are explicitly numbered, and not in the config space.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
These zeroings were taken from usb-storage long time ago. I examined
the submission paths and usb_fill_bulk_urb and found them unnecessary.
Signed-off-by: Pete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch fixes the following section mismatches:
<-- snip -->
...
WARNING: drivers/block/sunvdc.o(.text+0xf0): Section mismatch in reference from the function print_version() to the variable .devinit.data:version
WARNING: drivers/block/sunvdc.o(.text+0xf8): Section mismatch in reference from the function print_version() to the variable .devinit.data:version
...
<-- snip -->
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
In ace_fsm_dostate(), the variable 'i' was used only for passing
sector size of the request to end_that_request_first().
So I removed it and changed the code to pass the size in bytes
directly to __blk_end_request()
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Ed L. Cashin
Nick Piggin
Linus Torvalds
Josh Boyer
Geert Uytterhoeven
Randy Dunlap
Robert P. J. Day
David Woodhouse
Alexey Dobriyan
Stephen Neuendorffer
Grant Likely
Linus Torvalds
Christian Borntraeger
Anthony Liguori
Rusty Russell
Joe Perches
Pete Zaitcev
Adrian Bunk
Jens Axboe