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2007-06-20s390: qeth: wrong packet length in qdio headerFrank Pavlic
Packets Length in qdio header is broken when using EDDP on Layer2 devices. This leads to skb_under_panic on receiver system when running on z/VM GuestLAN devices. Signed-off-by: Frank Pavlic <fpavlic@de.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20s390: avoid inconsistent lock state in qethUrsula Braun
ipv6_regen_rndid in net/ipv6/addrconf.c makes use of "write_lock_bh" for its inet6_dev->lock. It may run in softirq-context. qeth makes use of "read_lock" for the same inet6_dev->lock. To avoid a potential deadlock situation, qeth should make use of "read_lock_bh" for its usages of inet6_dev->lock. Signed-off-by: Ursula Braun <braunu@de.ibm.com> Signed-off-by: Frank Pavlic <fpavlic@de.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20s390: qeth driver does not recoverUrsula Braun
While first recovery continues, the card issues a STARTLAN command itself. In this case qeth schedules another recovery. This second recovery is cancelled because of an already running first recovery. Stop first recovery in case of 0xe080. Signed-off-by: Ursula Braun <braunu@de.ibm.com> Signed-off-by: Frank Pavlic <fpavlic@de.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20s390: print correct level for HiperSockets devicesUrsula Braun
For real HiperSockets the EBCDIC-ASCII conversion is not necessary. This is only needed for z/VM GuestLAN devices. Signed-off-by: Ursula Braun <braunu@de.ibm.com> Signed-off-by: Frank Pavlic <fpavlic@de.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20bonding: Fix 802.3ad no carrier on "no partner found" instanceJay Vosburgh
Modify carrier state determination for 802.3ad mode to comply with section 43.3.9 of IEEE 802.3, which requires that "Links that are not successful candidates for aggregation (e.g., links that are attached to other devices that cannot perform aggregation or links that have been manually configured to be non-aggregatable) are enabled to operate as individual IEEE 802.3 links." Bug reported by Laurent Chavey <chavey@google.com>. This patch is an updated version of his patch that changes the wording of commentary and adds an update to the driver version. Signed-off-by: Jay Vosburgh <fubar@us.ibm.com> Signed-off-by: Laurent Chavey <chavey@google.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20bonding: Fix use after free in unregister pathJay Vosburgh
The following patch (based on a patch from Stephen Hemminger <shemminger@linux-foundation.org>) removes use after free conditions in the unregister path for the bonding master. Without this patch, an operation of the form "echo -bond0 > /sys/class/net/bonding_masters" would trigger a NULL pointer dereference in sysfs. I was not able to induce the failure with the non-sysfs code path, but for consistency I updated that code as well. I also did some testing of the bonding /proc file being open while the bond is being deleted, and didn't see any problems there. Signed-off-by: Jay Vosburgh <fubar@us.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20spidernet: checksum and ethtoolStephen Hemminger
It doesn't look like spidernet hardware can really checksum all protocols, the code looks like it does IPV4 only. If so, it should use NETIF_F_IP_CSUM instead of NETIF_F_HW_CSUM. The driver doesn't need it's own get/set for ethtool tx csum, and it should use the standard ethtool_op_get_link. Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: Linas Vepstas <linas@austin.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20spidernet: turn off descriptor chain end interrupt.Linas Vepstas
At some point, the transmit descriptor chain end interrupt (TXDCEINT) was turned on. This is a mistake; and it damages small packet transmit performance, as it results in a huge storm of interrupts. Turn it off. Signed-off-by: Linas Vepstas <linas@austin.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20spidernet: silence the ramfull messagesLinas Vepstas
Although the previous patch resolved issues with hangs when the RX ram full interrupt is encountered, there are still situations where lots of RX ramfull interrupts arrive, resulting in a noisy log in syslog. There is no need for this. Signed-off-by: Linas Vepstas <linas@austin.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20spidernet: Don't terminate the RX ringLinas Vepstas
The terminated RX ring will cause trouble during the RX ram full conditions, leading to a hung driver, as the hardware can't find the next descr. There is no real reason to terminate the RX ring; it doesn't make the operation any smooother, and it does require an extra sync. So don't do it. Signed-off-by: Linas Vepstas <linas@austin.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20spidernet: Cure RX ram full bugLinas Vepstas
This patch fixes a rare deadlock that can occur when the kernel is not able to empty out the RX ring quickly enough. Below follows a detailed description of the bug and the fix. As long as the OS can empty out the RX buffers at a rate faster than the hardware can fill them, there is no problem. If, for some reason, the OS fails to empty the RX ring fast enough, the hardware GDACTDPA pointer will catch up to the head, notice the not-empty condition, ad stop. However, RX packets may still continue arriving on the wire. The spidernet chip can save some limited number of these in local RAM. When this local ram fills up, the spider chip will issue an interrupt indicating this (GHIINT0STS will show ERRINT, and the GRMFLLINT bit will be set in GHIINT1STS). When te RX ram full condition occurs, a certain bug/feature is triggered that has to be specially handled. This section describes the special handling for this condition. When the OS finally has a chance to run, it will empty out the RX ring. In particular, it will clear the descriptor on which the hardware had stopped. However, once the hardware has decided that a certain descriptor is invalid, it will not restart at that descriptor; instead it will restart at the next descr. This potentially will lead to a deadlock condition, as the tail pointer will be pointing at this descr, which, from the OS point of view, is empty; the OS will be waiting for this descr to be filled. However, the hardware has skipped this descr, and is filling the next descrs. Since the OS doesn't see this, there is a potential deadlock, with the OS waiting for one descr to fill, while the hardware is waiting for a differen set of descrs to become empty. A call to show_rx_chain() at this point indicates the nature of the problem. A typical print when the network is hung shows the following: net eth1: Spider RX RAM full, incoming packets might be discarded! net eth1: Total number of descrs=256 net eth1: Chain tail located at descr=255 net eth1: Chain head is at 255 net eth1: HW curr desc (GDACTDPA) is at 0 net eth1: Have 1 descrs with stat=xa0800000 net eth1: HW next desc (GDACNEXTDA) is at 1 net eth1: Have 127 descrs with stat=x40800101 net eth1: Have 1 descrs with stat=x40800001 net eth1: Have 126 descrs with stat=x40800101 net eth1: Last 1 descrs with stat=xa0800000 Both the tail and head pointers are pointing at descr 255, which is marked xa... which is "empty". Thus, from the OS point of view, there is nothing to be done. In particular, there is the implicit assumption that everything in front of the "empty" descr must surely also be empty, as explained in the last section. The OS is waiting for descr 255 to become non-empty, which, in this case, will never happen. The HW pointer is at descr 0. This descr is marked 0x4.. or "full". Since its already full, the hardware can do nothing more, and thus has halted processing. Notice that descrs 0 through 254 are all marked "full", while descr 254 and 255 are empty. (The "Last 1 descrs" is descr 254, since tail was at 255.) Thus, the system is deadlocked, and there can be no forward progress; the OS thinks there's nothing to do, and the hardware has nowhere to put incoming data. This bug/feature is worked around with the spider_net_resync_head_ptr() routine. When the driver receives RX interrupts, but an examination of the RX chain seems to show it is empty, then it is probable that the hardware has skipped a descr or two (sometimes dozens under heavy network conditions). The spider_net_resync_head_ptr() subroutine will search the ring for the next full descr, and the driver will resume operations there. Since this will leave "holes" in the ring, there is also a spider_net_resync_tail_ptr() that will skip over such holes. Signed-off-by: Linas Vepstas <linas@austin.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20spidernet: null out skb pointer after its been used.Linas Vepstas
Avoid kernel crash in mm/slab.c due to double-free of pointer. If the ethernet interface is brought down while there is still RX traffic in flight, the device shutdown routine can end up trying to double-free an skb, leading to a crash in mm/slab.c Avoid the double-free by nulling out the skb pointer. Signed-off-by: Linas Vepstas <linas@austin.ibm.com> Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-06-20Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6: firewire: Only set client->iso_context if allocation was successful. ieee1394: fix to ether1394_tx in ether1394.c firewire: fix hang after card ejection
2007-06-20Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband: IB/mlx4: Make sure inline data segments don't cross a 64 byte boundary IB/mlx4: Handle FW command interface rev 3 IB/mlx4: Handle buffer wraparound in __mlx4_ib_cq_clean() IB/mlx4: Get rid of max_inline_data calculation IB/mlx4: Handle new FW requirement for send request prefetching IB/mlx4: Fix warning in rounding up queue sizes IB/mlx4: Fix handling of wq->tail for send completions
2007-06-21firewire: Only set client->iso_context if allocation was successful.Kristian Høgsberg
This patch fixes an OOPS on cdev release for an fd where iso context creation failed. Signed-off-by: Kristian Høgsberg <krh@redhat.com> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2007-06-20Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linusLinus Torvalds
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: [MIPS] Don't drag a platform specific header into generic arch code.
2007-06-20Merge branch 'merge' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc * 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: [POWERPC] Fix powermac late initcall to only run on powermac [POWERPC] PowerPC: Prevent data exception in kernel space (32-bit)
2007-06-20Fix up CREDIT entry orderingLi Yang
Reorder my CREDIT entry to make it in alphabetic order by last name. Signed-off-by: Li Yang <leoli@freescale.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-20x86_64: fix link warning between for .text and .init.textYinghai Lu
WARNING: arch/x86_64/kernel/built-in.o(.text+0xace9): Section mismatch: reference to .init.text: (between 'get_mtrr_state' and 'mtrr_wrmsr') WARNING: arch/x86_64/kernel/built-in.o(.text+0xad09): Section mismatch: reference to .init.text: (between 'get_mtrr_state' and 'mtrr_wrmsr') WARNING: arch/x86_64/kernel/built-in.o(.text+0xad38): Section mismatch: reference to .init.text: (between 'get_mtrr_state' and 'mtrr_wrmsr') WARNING: drivers/built-in.o(.text+0x3a680): Section mismatch: reference to .init.text:acpi_map_pxm_to_node (between 'acpi_get_node' and 'acpi_lock_ac_dir') AK: also marked mtrr_bp_init __init to avoid some more warnings Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Andi Kleen <ak@suse.de> Acked-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-20x86: change_page_attr bandaidsAndi Kleen
- Disable CLFLUSH again; it is still broken. Always do WBINVD. - Always flush in the i386 case, not only when there are deferred pages. These are both brute-force inefficient fixes, to be improved next release cycle. The changes to i386 are a little more extensive than strictly needed (some dead code added), but it is more similar to the x86-64 version now and the dead code will be used soon. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-20x86: Disable KPROBES with DEBUG_RODATA for nowAndi Kleen
Right now Kprobes cannot write to the write protected kernel text when DEBUG_RODATA is enabled. Disallow this in Kconfig for now. Temporary fix for 2.6.22. In .23 add code to temporarily unprotect it. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-20x86: Only make Macintosh drivers default on MacsAndi Kleen
It's already annoying that they appear on x86 now -- that's for the 3button emulation needed on x86 macs -- but at least don't make them default. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-20x86_64: Quieten Atari keyboard warnings in KconfigAndi Kleen
Not directly related to x86, but I got tired of seeing these warnings on every kconfig update when building on a non m68k box: drivers/input/keyboard/Kconfig:170:warning: 'select' used by config symbol 'KEYBOARD_ATARI' refers to undefined symbol 'ATARI_KBD_CORE' drivers/input/mouse/Kconfig:182:warning: 'select' used by config symbol 'MOUSE_ATARI' refers to undefined symbol 'ATARI_KBD_CORE' I moved the definition of ATARI_KBD_CORE into drivers/input/keyboard/Kconfig so it's always seen by Kconfig. Cc: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Roman Zippel <zippel@linux-m68k.org> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-20x86: Disable DAC on VIA bridgesAndi Kleen
Several reports that VIA bridges don't support DAC and corrupt data. I don't know if it's fixed, but let's just blacklist them all for now. It can be overwritten with iommu=usedac Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-20x86_64: Fix eventd/timerfd syscallsAndi Kleen
They had the same syscall number. Pointed out by Davide Libenzi Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-20x86_64: Fix readahead/sync_file_range/fadvise64 compat callsAndi Kleen
Correctly convert the u64 arguments from 32bit to 64bit. Pointed out by Heiko Carstens. I guess this proves Linus' theory that nobody uses the more exotic Linux specific syscalls. It wasn't discovered by a user. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-20[MIPS] Don't drag a platform specific header into generic arch code.Ralf Baechle
For some platforms it's definitions may conflict. So that's the one-liner. The rest is 10 square kilometers of collateral damage fixup this include used to paper over. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-06-20[POWERPC] Fix powermac late initcall to only run on powermacTony Breeds
Current ppc64_defconfig kernel fails to boot on iSeries, dying with: Unable to handle kernel paging request for data at address 0x00000000 Faulting instruction address: 0xc00000000071b258 Oops: Kernel access of bad area, sig: 11 [#1] SMP NR_CPUS=32 iSeries <snip> NIP [c00000000071b258] .iSeries_src_init+0x34/0x64 LR [c000000000701bb4] .kernel_init+0x1fc/0x3bc Call Trace: [c000000007d0be30] [0000000000008000] 0x8000 (unreliable) [c000000007d0bea0] [c000000000701bb4] .kernel_init+0x1fc/0x3bc [c000000007d0bf90] [c0000000000262d4] .kernel_thread+0x4c/0x68 Instruction dump: e922cba8 3880ffff 78840420 f8010010 f821ff91 60000000 e8090000 78095fe3 4182002c e922cb58 e862cbb0 e9290140 <e8090000> f8410028 7c0903a6 e9690010 Kernel panic - not syncing: Attempted to kill init! This happens because some powermac code unconditionally sets ppc_md.progress to NULL. This patch makes sure the powermac late initcall is only run on powermac machines. Signed-off-by: Tony Breeds <tony@bakeyournoodle.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-20[POWERPC] PowerPC: Prevent data exception in kernel space (32-bit)Segher Boessenkool
The "is_exec" branch of the protection check in do_page_fault() didn't do anything on 32-bit PowerPC. So if a userland program jumps to a page with Linux protection flags "---p", all the tests happily fall through, and handle_mm_fault() is called, which in turn calls handle_pte_fault(), which calls update_mmu_cache(), which goes flush the dcache to a page with no access rights. Boom. This fixes it. Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org> Cc: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-19[POWERPC] rheap - eliminates internal fragments caused by alignmentLi Yang
The patch adds fragments caused by rh_alloc_align() back to free list, instead of allocating the whole chunk of memory. This will greatly improve memory utilization managed by rheap. It solves MURAM not enough problem with 3 UCCs enabled on MPC8323. Signed-off-by: Li Yang <leoli@freescale.com> Acked-by: Joakim Tjernlund <joakim.tjernlund@transmode.se> Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2007-06-19Merge master.kernel.org:/pub/scm/linux/kernel/git/lethal/sh64-2.6Linus Torvalds
* master.kernel.org:/pub/scm/linux/kernel/git/lethal/sh64-2.6: sh64: Handle -ERESTART_RESTARTBLOCK for restartable syscalls.
2007-06-19Merge master.kernel.org:/pub/scm/linux/kernel/git/lethal/sh-2.6Linus Torvalds
* master.kernel.org:/pub/scm/linux/kernel/git/lethal/sh-2.6: sh: Handle -ERESTART_RESTARTBLOCK for restartable syscalls. sh: oops_enter()/oops_exit() in die(). sh: Fix restartable syscall arg5 clobbering.
2007-06-19Merge branch 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6Linus Torvalds
* 'for-linus' of git://git390.osdl.marist.edu/pub/scm/linux-2.6: [S390] Move psw_set_key. [S390] Add oops_enter()/oops_exit() calls to die(). [S390] Print list of modules on die(). [S390] Fix yet another two section mismatches. [S390] Fix zfcpdump header [S390] Missing blank when appending cio_ignore kernel parameter
2007-06-19Merge branch 'for-linus' of git://oss.sgi.com:8090/xfs/xfs-2.6Linus Torvalds
* 'for-linus' of git://oss.sgi.com:8090/xfs/xfs-2.6: [XFS] Update the MAINTAINERS file entry for XFS - change git repo name. [XFS] s/memclear_highpage_flush/zero_user_page/ [XFS] Update the MAINTAINERS file entry for XFS.
2007-06-19[S390] Move psw_set_key.Heiko Carstens
Move psw_set_key() from ptrace.h to processor.h which is a more suitable place for it. In addition the moves makes the function invisible to user space. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-06-19[S390] Add oops_enter()/oops_exit() calls to die().Heiko Carstens
This is mainly to switch off all potentially debugging stuff that won't report anything useful after an oops happened. Besided that setting pause_on_oops will work too, but doesn't make too much sense on s390. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-06-19[S390] Print list of modules on die().Heiko Carstens
Print list of modules on die() like a lot of other architectures do. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-06-19[S390] Fix yet another two section mismatches.Heiko Carstens
WARNING: arch/s390/kernel/built-in.o(.text+0xb92a): Section mismatch: reference to .init.text:start_secondary (between 'restart_addr' and 'stack_overflow') WARNING: arch/s390/appldata/built-in.o(.data+0xdc): Section mismatch: reference to .init.text: (between 'appldata_nb' and 'appldata_timer_lock') Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-06-19[S390] Fix zfcpdump headerMichael Holzheu
Added members for volume number and real memory size to header information. Signed-off-by: Michael Holzheu <holzheu@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-06-19[S390] Missing blank when appending cio_ignore kernel parameterMichael Holzheu
When appending the 'cio_ignore' kernel parameter to the command line, a blank has to be inserted in order to separate 'cio_ignore' from the preceding kernel parameters. Signed-off-by: Michael Holzheu <holzheu@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-06-19[XFS] Update the MAINTAINERS file entry for XFS - change git repo name.Tim Shimmin
Make the git repository bare and so give it the conventional .git suffix. Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-06-19[XFS] s/memclear_highpage_flush/zero_user_page/Christoph Hellwig
SGI-PV: 957103 SGI-Modid: xfs-linux-melb:xfs-kern:28678a Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-06-19Merge branch 'for-linus' of git://oss.sgi.com:8090/xfs/xfs-2.6 into for-linusTim Shimmin
2007-06-19[POWERPC] Fix snd-powermac refcounting bugsBenjamin Herrenschmidt
The old snd-powermac driver has some serious refcounting issues when initialisation fails, which is the case on all new machines with a layout-id since those are handled by the new snd-aoa driver. Some of those bugs seem to have been under the radar for some time (like double pci_dev_put), but one was actually added in 2.6.22 with Stephen attempt at teaching refcounting to the driver which didn't do it at all. This patch fixes both, thus removing all sort of kref errors that would happen if that driver gets loaded on a G5 machine or a recent PowerBook due to OF nodes left around with a 0 refcount. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-19sh64: Handle -ERESTART_RESTARTBLOCK for restartable syscalls.Paul Mundt
The current implementation only handles -ERESTARTNOHAND, whereas we also need to handle -ERESTART_RESTARTBLOCK in the handle_signal() case for restartable system calls. Follows the sh change. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-06-19sh: Handle -ERESTART_RESTARTBLOCK for restartable syscalls.Paul Mundt
The current implementation only handles -ERESTARTNOHAND, whereas we also need to handle -ERESTART_RESTARTBLOCK in the handle_signal() case for restartable system calls. As noted by Carl: This fixes the LTP test nanosleep03 - the current kernel causes -ERESTART_RESTARTBLOCK to reach user space rather than the correct -EINTR. Reported-by: Carl Shaw <shaw.carl@gmail.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-06-18Fix possible runqueue lock starvation in wait_task_inactive()Linus Torvalds
Miklos Szeredi reported very long pauses (several seconds, sometimes more) on his T60 (with a Core2Duo) which he managed to track down to wait_task_inactive()'s open-coded busy-loop. He observed that an interrupt on one core tries to acquire the runqueue-lock but does not succeed in doing so for a very long time - while wait_task_inactive() on the other core loops waiting for the first core to deschedule a task (which it wont do while spinning in an interrupt handler). This rewrites wait_task_inactive() to do all its waiting optimistically without any locks taken at all, and then just double-check the end result with the proper runqueue lock held over just a very short section. If there were races in the optimistic wait, of a preemption event scheduled the process away, we simply re-synchronize, and start over. So the code now looks like this: repeat: /* Unlocked, optimistic looping! */ rq = task_rq(p); while (task_running(rq, p)) cpu_relax(); /* Get the *real* values */ rq = task_rq_lock(p, &flags); running = task_running(rq, p); array = p->array; task_rq_unlock(rq, &flags); /* Check them.. */ if (unlikely(running)) { cpu_relax(); goto repeat; } /* Preempted away? Yield if so.. */ if (unlikely(array)) { yield(); goto repeat; } Basically, that first "while()" loop is done entirely without any locking at all (and doesn't check for the case where the target process might have been preempted away), and so it's possibly "incorrect", but we don't really care. Both the runqueue used, and the "task_running()" check might be the wrong tests, but they won't oops - they just mean that we could possibly get the wrong results due to lack of locking and exit the loop early in the case of a race condition. So once we've exited the loop, we then get the proper (and careful) rq lock, and check the running/runnable state _safely_. And if it turns out that our quick-and-dirty and unsafe loop was wrong after all, we just go back and try it all again. (The patch also adds a lot of comments, which is the actual bulk of it all, to make it more obvious why we can do these things without holding the locks). Thanks to Miklos for all the testing and tracking it down. Tested-by: Miklos Szeredi <miklos@szeredi.hu> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-18sched: fix SysRq-N (normalize RT tasks)Ingo Molnar
Gene Heskett reported the following problem while testing CFS: SysRq-N is not always effective in normalizing tasks back to SCHED_OTHER. The reason for that turns out to be the following bug: - normalize_rt_tasks() uses for_each_process() to iterate through all tasks in the system. The problem is, this method does not iterate through all tasks, it iterates through all thread groups. The proper mechanism to enumerate over all threads is to use a do_each_thread() + while_each_thread() loop. Reported-by: Gene Heskett <gene.heskett@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-18Merge master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6Linus Torvalds
* master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6: [SCSI] ESP: Don't forget to clear ESP_FLAG_RESETTING. [SCSI] fusion: fix for BZ 8426 - massive slowdown on SCSI CD/DVD drive
2007-06-18Fix signalfd interaction with thread-private signalsBenjamin Herrenschmidt
Don't let signalfd dequeue private signals off other threads (in the case of things like SIGILL or SIGSEGV, trying to do so would result in undefined behaviour on who actually gets the signal, since they are force unblocked). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>