With a fiber or serdes NIC installed the driver was causing a null pointer
dereference on driver unload.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
The internal name was used in comments, replaced with silicon part number.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
The L1 hardware contains a bug that flags a fragmented IP packet
as having an incorrect TCP/UDP checksum, even though the packet
is perfectly valid and its checksum is correct. There's no way to
distinguish between one of these good packets and a packet that
actually contains a TCP/UDP checksum error, so all we can do is
allow the packet to be handed up to the higher layers and let it
be sorted out there.
Add a comment describing this condition and remove the code that
currently fails to handle what may or may not be a checksum error.
Signed-off-by: Jay Cliburn <jacliburn@bellsouth.net>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
There are currently no devices supported by the e1000e driver which need
ioport resources, remove the test for it and all unnecessary code
associated with it (struct e1000_adapter elements, local variables, etc.)
Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
a few people seem to have problems maintaining gigabit link
and it was root caused to an interaction between the managability
firmware on the host and the driver, not communicating.
The form of communication they use is the drv_load bit.
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
82573 EEPROMs have been shipped out with known issues. While most
people will never see the issues some people do and we know
how to address them. Warn the user if we find one of these
EEPROM issues.
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
The ndev_* printk's are too lenghty and we don't need to specify
the adapter/netdev struct at all, making this a lot more readable.
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Set 64bits consistent DMA mask since it improves performance
in some cases. No need to check the return value since it is
not required for the driver to work.
Signed-off-by: Brice Goglin <brice@myri.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
This re-introduces commit 2b14290078,
which was reverted due to the regression it caused by commit
fca082c9f1.
That regression was not root-caused by the original commit, it was just
uncovered by it, and the real fix was done by Alan Stern in commit
580da34847 ("Fix USB storage hang on
command abort").
We can thus re-introduce the change that was confirmed by Alan Jenkins
to be still required by his odd card reader.
Cc: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (78 commits)
AX.25: Fix sysctl registration if !CONFIG_AX25_DAMA_SLAVE
pktgen: mac count
pktgen: random flow
bridge: Eliminate unnecessary forward delay
bridge: fix compile warning in net/bridge/br_netfilter.c
ipv4: remove unused field in struct flowi (include/net/flow.h).
tg3: Fix 'scheduling while atomic' errors
net: Kill plain NET_XMIT_BYPASS.
net_sched: Add qdisc __NET_XMIT_BYPASS flag
net_sched: Add qdisc __NET_XMIT_STOLEN flag
iwl3945: fix merge mistake for packet injection
iwlwifi: grap nic access before accessing periphery registers
iwlwifi: decrement rx skb counter in scan abort handler
iwlwifi: fix unhandled interrupt when HW rfkill is on
iwlwifi: implement iwl5000_calc_rssi
iwlwifi: memory allocation optimization
iwlwifi: HW bug fixes
p54: Fix potential concurrent access to private data
rt2x00: Disable link tuning in rt2500usb
iwlwifi: Don't use buffer allocated on the stack for led names
...
Since 49ffcf8f99 ("sysctl: update
sysctl_check_table") setting struct ctl_table.procname = NULL does no
longer work as it used to the way the AX.25 code is expecting it to
resulting in the AX.25 sysctl registration code to break if
CONFIG_AX25_DAMA_SLAVE was not set as in some distribution kernels.
Kernel releases from 2.6.24 are affected.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
dst_mac_count and src_mac_count patch from Eneas Hunguana
We have sent one mac address to much.
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
Random flow generation has not worked. This fixes it.
Signed-off-by: Robert Olsson <robert.olsson@its.uu.se>
Signed-off-by: David S. Miller <davem@davemloft.net>
From: Stephen Hemminger <shemminger@vyatta.com>
Based upon original patch by Herbert Xu, which contained
the following problem description:
--------------------
When the forward delay is set to zero, we still delay the setting
of the forwarding state by one or possibly two timers depending
on whether STP is enabled. This could either turn out to be
instantaneous, or horribly slow depending on the load of the
machine.
As there is nothing preventing us from enabling forwarding straight
away, this patch eliminates this potential delay by executing the
code directly if the forward delay is zero.
The effect of this problem is that immediately after the carrier
comes on a port, the bridge will drop all packets received from
that port until it enters forwarding mode, thus causing unnecessary
packet loss.
Note that this patch doesn't fully remove the delay due to the
link watcher. We should also check the carrier state when we
are about to drop an incoming packet because the port is disabled.
But that's for another patch.
--------------------
This version of the fix takes a different approach, in that
it just does the state change directly.
Signed-off-by: David S. Miller <davem@davemloft.net>
mips allmodconfig:
drivers/media/video/vino.c: In function `vino_free_buffer_with_count':
drivers/media/video/vino.c:811: warning: passing arg 1 of `virt_to_phys' makes pointer from integer without a cast
drivers/media/video/vino.c: In function `vino_allocate_buffer':
drivers/media/video/vino.c:889: warning: passing arg 1 of `virt_to_phys' makes pointer from integer without a cast
drivers/media/video/vino.c: In function `vino_ioctl':
drivers/media/video/vino.c:4364: error: implicit declaration of function `video_usercopy'
The patch fixes the error, but not the warnings.
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
gcc 4.3.0 correctly emits the following warnings.
When a vma covering addr is found, find_vma_prepare indeed returns without
setting pprev, rb_link, and rb_parent.
mm/mmap.c: In function `insert_vm_struct':
mm/mmap.c:2085: warning: `rb_parent' may be used uninitialized in this function
mm/mmap.c:2085: warning: `rb_link' may be used uninitialized in this function
mm/mmap.c:2084: warning: `prev' may be used uninitialized in this function
mm/mmap.c: In function `copy_vma':
mm/mmap.c:2124: warning: `rb_parent' may be used uninitialized in this function
mm/mmap.c:2124: warning: `rb_link' may be used uninitialized in this function
mm/mmap.c:2123: warning: `prev' may be used uninitialized in this function
mm/mmap.c: In function `do_brk':
mm/mmap.c:1951: warning: `rb_parent' may be used uninitialized in this function
mm/mmap.c:1951: warning: `rb_link' may be used uninitialized in this function
mm/mmap.c:1949: warning: `prev' may be used uninitialized in this function
mm/mmap.c: In function `mmap_region':
mm/mmap.c:1092: warning: `rb_parent' may be used uninitialized in this function
mm/mmap.c:1092: warning: `rb_link' may be used uninitialized in this function
mm/mmap.c:1089: warning: `prev' may be used uninitialized in this function
Hugh adds: in fact, none of find_vma_prepare's callers use those values
when a vma is found to be already covering addr, it's either an error or
an occasion to munmap and repeat. Okay, let's quieten the compiler (but I
would prefer it if pprev, rb_link and rb_parent were meaningful in that
case, rather than whatever's in them from descending the tree).
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: "Ryan Hope" <rmh3093@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A documentation cleanup patch. With a minor tweak to clarify units for
kbs.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: mark gross <mgross@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
proc: fix warnings
fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 3 has type 'u64'
fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 4 has type 'u64'
fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 5 has type 'u64'
fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 6 has type 'u64'
fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 7 has type 'u64'
fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 8 has type 'u64'
fs/proc/base.c:2429: warning: format '%llu' expects type 'long long unsigned int', but argument 9 has type 'u64'
Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
Acked-by: Andrea Righi <righi.andrea@gmail.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/omfs/inode.c:495: warning: format '%llx' expects type 'long long
unsigned int', but argument 2 has type 'u64'
fs/omfs/inode.c:495: warning: format '%llx' expects type 'long
long unsigned int', but argument 3 has type '__be64'
Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
Acked-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix handling of nested structs or unions. The regex to strip (eliminate)
nested structs or unions was limited to only 0 or 1 matches. This can
cause an uneven number of left/right braces to be stripped, which causes
this:
Warning(linux-2.6.27-rc1-git2//include/net/mac80211.h:336): No description found for parameter '}'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
get_order() takes byte-sized input, not a page-granular one.
Irrespective of this fix I'm inclined to believe that this doesn't work
right anyway - bitmap_allocate_region() has an implicit assumption of
'pos' being suitable for 'order', which this function doesn't seem to
enforce (and since it's being called with a byte-granular value there's no
reason to believe that the callers would make sure device_addr is passed
accordingly - it's also not documented that way).
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/video/aty/atyfb_base.c:2663: warning: 'aty_resume_chip' defined
but not used
Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Ville Syrjala <syrjala@sci.fi>
Cc: Antonino A. Daplas <adaplas@pol.net>
Cc: Mark Asselstine <asselsm@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
of_node_put is needed before discarding a value received from
of_find_node_by_type, eg in error handling code.
The semantic patch that makes the change is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@@
struct device_node *n;
struct device_node *n1;
struct device_node *n2;
statement S;
identifier f1,f2;
expression E1,E2;
constant C;
@@
n = of_find_node_by_type(...)
...
if (!n) S
... when != of_node_put(n)
when != n1 = f1(n,...)
when != E1 = n
when any
when strict
(
+ of_node_put(n);
return -C;
|
of_node_put(n);
|
n2 = f2(n,...)
|
E2 = n
|
return ...;
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Timur Tabi <timur@freescale.com>
Cc: York Sun <yorksun@freescale.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The name of the i2c buses shows in the output of "i2cdetect -l", so
it's important to give informative names.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If the 'clear' command is used on the frame buffer with a logo the upper
area is filled by few lines but not scrolled anymore.
Fix this by removing the protected area for the logo if any part of the
logo is cleared.
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I have a new PCI-E radeon RV380 series card (PCI device ID 5b64) that
hangs in my sparc64 boxes when the init scripts set the font. The problem
goes away if I disable acceleration.
I haven't figured out that bug yet, but along the way I found some
corrections to make based upon some auditing.
1) The RB2D_DC_FLUSH_ALL value used by the kernel fb driver
and the XORG video driver differ. I've made the kernel
match what XORG is using.
2) In radeonfb_engine_reset() we have top-level code structure
that roughly looks like:
if (family is 300, 350, or V350)
do this;
else
do that;
...
if (family is NOT 300, OR
family is NOT 350, OR
family is NOT V350)
do another thing;
this last conditional makes no sense, is always true,
and obviously was likely meant to be "family is NOT
300, 350, or V350". So I've made the code match the
intent.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These functions have been deprecated for some time now but remained until
all legacy callers could be removed. With a few commits in 2.6.26 this
has happened so now we can remove these deprecated functions.
Signed-off-by: Mark Asselstine <mark.asselstine@windriver.com>
Reviewed-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add the missing MODULE_ALIAS() to the pwm_backlight driver.
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make the error paths in the pwm_backlight driver more informative in the
probe path, especially for the times that it finds an error.
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Acked-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since we use the write complete interrupt, wait for it
to complete before sleeping so we don't wake right back up due to it
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Cc: David Brownell <david-b@pacbell.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While I'm glad to finally see the hole fixed whereby passing an invalid
IRQ trigger type to request_irq() would be ignored, the current diagnostic
isn't quite useful. Fixed by also listing the trigger type which was
rejected.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change __down_common() to use signal_pending_state() instead of open
coding.
The changes in kernel/semaphore.o are just artifacts, the state checks are
optimized away.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In relay's current read implementation, if the buffer is completely full
but hasn't triggered the buffer-full condition (i.e. the last write
didn't cross the subbuffer boundary) and the last subbuffer is exactly
full, the subbuffer accounting code erroneously finds nothing available.
This patch fixes the problem.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Andrea Righi <righi.andrea@gmail.com>
Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This adds an SPI driver for the SPI controller found in various Marvell
Orion ARM SoCs. It currently supports only one slave, which must use SPI
mode 0.
[dbrownell@users.sourceforge.net: cleanups, meet specs, pass "sparse"]
Signed-off-by: Shadi Ammouri <shadi@marvell.com>
Signed-off-by: Saeed Bishara <saeed@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
curr_queue is a local variable in a for loop, and it's being initialized
at the start of each loop. So any assignment at the end of the loop is
pointless.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Cc: Mike Miller <mike.miller@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
commit 20e061fb75
Author: Ondrej Zajicek <santiago@crfreenet.org>
Date: Mon Apr 28 02:15:18 2008 -0700
fbdev: framebuffer_alloc() fixes
Correct the dev arg of framebuffer_alloc() in arkfb, s3fb and vt8623fb.
causes a null-pointer deref because "info->dev is NULL, info was just
kzallocated".
Signed-off-by: Ondrej Zajicek <santiago@crfreenet.org>
Reported-by: "MadLoisae@gmx.net" <MadLoisae@gmx.net>
Tested-by: "MadLoisae@gmx.net" <MadLoisae@gmx.net>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: <stable@kernel.org> [2.6.26.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current implementation reports the structure name as
VMCOREINFO_OSRELEASE in VMCOREINFO, e.g.
VMCOREINFO_OSRELEASE=init_uts_ns.name.release
That doesn't make sense because it's always the same. Instead, use the
value, e.g.
VMCOREINFO_OSRELEASE=2.6.26-rc3
That's also what the 'makedumpfile -g' does.
Signed-off-by: Bernhard Walle <bwalle@suse.de>
Cc: "Ken'ichi Ohmichi" <oomichi@mxs.nes.nec.co.jp>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
gcc-3.2:
mm/mm_init.c:77:1: directives may not be used inside a macro argument
mm/mm_init.c:76:47: unterminated argument list invoking macro "mminit_dprintk"
mm/mm_init.c: In function `mminit_verify_pageflags_layout':
mm/mm_init.c:80: `mminit_dprintk' undeclared (first use in this function)
mm/mm_init.c:80: (Each undeclared identifier is reported only once
mm/mm_init.c:80: for each function it appears in.)
mm/mm_init.c:80: syntax error before numeric constant
Also fix a typo in a comment.
Reported-by: Adrian Bunk <bunk@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alexander Duyck