When a snapshot becomes invalid, s->valid is set to 0. In this state, a
snapshot can no longer be accessed.
When s->lock is acquired, before doing anything else, s->valid must be checked
to ensure the snapshot remains valid.
This patch eliminates some races (that may cause panics) by adding some
missing checks. At the same time, some unnecessary levels of indentation are
removed and snapshot invalidation is moved into a single function that always
generates a device-mapper event.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The siblings "list" is used unsafely at the moment.
Firstly, only the element on the list being changed gets locked (via the
snapshot lock), not the next and previous elements which have pointers that
are also being changed.
Secondly, if you have two or more snapshots and write to the same chunk a
second time before every snapshot has finished making its private copy of the
data, if you're unlucky, _origin_write() could attempt its list_merge() and
dereference a 'last' pointer to a pending_exception structure that has just
been freed.
Analysis reveals that the list is actually only there for reference counting.
If 5 pending_exceptions are needed in origin_write, then the 5 are joined
together into a 5-element list - without a separate list head because there's
nowhere suitable to store it. As the pending_exceptions complete, they are
removed from the list one-by-one and any contents of origin_bios get moved
across to one of the remaining pending_exceptions on the list. Whichever one
is last is detected because list_empty() is then true and the origin_bios get
submitted.
The fix proposed here uses an alternative reference counting mechanism by
choosing one of the pending_exceptions as primary and maintaining an atomic
counter there.
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Say you have several snapshots of the same origin and then you issue a write
to some place in the origin for the first time.
Before the device-mapper snapshot target lets the write go through to the
underlying device, it needs to make a copy of the data that is about to be
overwritten. Each snapshot is independent, so it makes one copy for each
snapshot.
__origin_write() loops through each snapshot and checks to see whether a copy
is needed for that snapshot. (A copy is only needed the first time that data
changes.)
If a copy is needed, the code allocates a 'pending_exception' structure
holding the details. It links these together for all the snapshots, then
works its way through this list and submits the copying requests to the kcopyd
thread by calling start_copy(). When each request is completed, the original
pending_exception structure gets freed in pending_complete().
If you're very unlucky, this structure can get freed *before* the submission
process has finished walking the list.
This patch:
1) Creates a new temporary list pe_queue to hold the pending exception
structures;
2) Does all the bookkeeping up-front, then walks through the new list
safely and calls start_copy() for each pending_exception that needed it;
3) Avoids attempting to add pe->siblings to the list if it's already
connected.
[NB This does not fix all the races in this code. More patches will follow.]
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use ARRAY_SIZE macro instead of sizeof(x)/sizeof(x[0]) and remove
duplicates of ARRAY_SIZE. Some coding style and trailing whitespaces are
also fixed.
Compile-tested where possible (some are other arch or BROKEN)
Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There are more sparse warnings but fixing those will require some more work
than I want to do without hardware for testing at hand.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Quadro NVS280 is a dual-head PCIe card with PCI ID 10de:00fd and subsystem ID
10de:0215.
Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove code that can never be reached.
Coverity Bug 67
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove unnecessary NULL check. Being a function private to the driver,
out_edid can never be NULL.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove unnecessary NULL check, as struct info will never be NULL.
Coverity Bug 835
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove unnecessary NULL check, as struct info will never be NULL.
Coverity Bug 836
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A set of 3 small bugfixes, all of which are related to bogus return values
of fb colormap-setting functions.
First, fb_alloc_cmap returns -1 if memory allocation fails. This is a hard
condition to reproduce since you'd have to be really low on memory, but from
studying the contexts in which it is called, I think this function should be
returning a negative errno, and the -1 will be seen as an EPERM. Switching it
to -ENOMEM makes sense.
Second, the store_cmap function which is called for writes to
/sys/class/graphics/fb0/color_map returns 0 for success, but it should be
returning the count of bytes written since its return value ends up in
userspace as the result of the write() syscall.
Third, radeonfb returns 1 instead of a negative errno when FBIOPUTCMAP is
called with an oversized colormap. This is seen in userspace as a return
value of 1 from the ioctl() syscall with errno left unchanged. A more
useful return value would be -EINVAL.
Signed-off-by: Alan Curry <pacman@TheWorld.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
DDC reading via the Video BIOS may take several tens of seconds with some
combination of display cards and monitors.
Make this option configurable. It defaults to `y' to minimise disruption.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A few cleanups which were done to almost all i2c drivers some times
ago, but matroxfb_maven was forgotten:
* Don't allocate two different structures at once.
* Use kzalloc instead of kmalloc+memset.
* Use strlcpy instead of strcpy.
* Drop duplicate error message on client deregistration failure.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Petr Vandrovec <vandrove@vc.cvut.cz>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
insmod will tell us when the module failed to load. We do no further
processing on the return from i2c_add_driver(), so just return what
i2c_add_driver() did, instead of storing it.
Add __init/__exit annotations while we're at it.
Signed-off-by: Arthur Othieno <apgo@patchbomb.org>
Acked-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A framebuffer driver for the display controller in AMD Geode GX processors
(Geode GX533, Geode GX500 etc.). Tested at 640x480, 800x600, 1024x768 and
1280x1024 at 8, 16, and 24 bpp with both CRT and TFT. No accelerated features
currently implemented and compression remains disabled.
This driver requires that the BIOS (or the SoftVG/Firmbase code in the BIOS)
has created an appropriate virtual PCI header.
Signed-off-by: David Vrabel <dvrabel@arcom.com>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add suspend and resume hooks to make software suspend more reliable. Resuming
from standby should generally work. Resuming from mem and from disk requires
that the GPU is disabled. Adding these to the suspend script...
fbset -accel false -a
/* suspend here */
fbset -accel true -a
... should generally work. In addition, resuming from mem requires that the
video card has to be POSTed by the BIOS or some other utility.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The scrollback buffer of the VGA console is located in VGA RAM. This RAM
is fixed in size and is very small. To make the scrollback buffer larger,
it must be placed instead in System RAM.
This patch adds this feature. The feature and the size of the buffer are
made as a kernel config option. Besides consuming kernel memory, this
feature will slow down the console by approximately 20%.
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Jindrich Makovicka <makovick@kmlinux.fjfi.cvut.cz>
Cc: Martin Mares <mj@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This corrects cursor resize on ega boards: registers are write-only, so we
shouldn't even try to read them. And on ega, 31/30 produces a flat cursor.
Using 31/31 is better: except with 32 pixels high fonts, it shouldn't show
up.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove the assumption that pnp_register_card_driver() returns the
number of devices claimed. And fix some __init/__devinit issues.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Adam Belay <ambx1@neo.rr.com>
Cc: Jaroslav Kysela <perex@suse.cz>
Acked-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Alasdair G Kergon
Adrian Bunk
Tobias Klauser
Olaf Hering
Ralf Baechle
Pavel Roskin
Antonino A. Daplas
Alan Curry
Jean Delvare
Arthur Othieno
David Vrabel
Samuel Thibault
Bjorn Helgaas