linux/kernel/irq, branch v2.6.34

Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2010-04-06T20:03:22Z

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: genirq: Force MSI irq handlers to run with interrupts disabled

genirq: Force MSI irq handlers to run with interrupts disabled

2010-03-31T13:48:38Z

Network folks reported that directing all MSI-X vectors of their multi queue NICs to a single core can cause interrupt stack overflows when enough interrupts fire at the same time. This is caused by the fact that we run interrupt handlers by default with interrupts enabled unless the driver reuqests the interrupt with the IRQF_DISABLED set. The NIC handlers do not set this flag, so simultaneous interrupts can nest unlimited and cause the stack overflow. The only safe counter measure is to run the interrupt handlers with interrupts disabled. We can't switch to this mode in general right now, but it is safe to do so for MSI interrupts. Force IRQF_DISABLED for MSI interrupt handlers. Signed-off-by: Thomas Gleixner Cc: Andi Kleen Cc: Linus Torvalds Cc: Andrew Morton Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Alan Cox Cc: David Miller Cc: Greg Kroah-Hartman Cc: Arnaldo Carvalho de Melo Cc: stable@kernel.org

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32Z

percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo Guess-its-ok-by: Christoph Lameter Cc: Ingo Molnar Cc: Lee Schermerhorn

Merge branch 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2010-03-26T22:09:06Z

* 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: genirq: Move two IRQ functions from .init.text to .text genirq: Protect access to irq_desc->action in can_request_irq() genirq: Prevent oneshot irq thread race

genirq: Move two IRQ functions from .init.text to .text

2010-03-24T13:38:23Z

Both functions should not be marked as __init, since they be called from modules after the init section is freed. Signed-off-by: Henrik Kretzschmar Cc: Yinghai Lu Cc: Peter Zijlstra Cc: Jiri Kosina LKML-Reference: <1269431961-5731-1-git-send-email-henne@nachtwindheim.de> Signed-off-by: Thomas Gleixner

genirq: Protect access to irq_desc->action in can_request_irq()

2010-03-24T13:38:23Z

can_request_irq() accesses and dereferences irq_desc->action w/o holding irq_desc->lock. So action can be freed on another CPU before it's dereferenced. Unlikely, but ... Protect it with desc->lock. Signed-off-by: Thomas Gleixner

genirq: Prevent oneshot irq thread race

2010-03-10T16:45:14Z

Lars-Peter pointed out that the oneshot threaded interrupt handler code has the following race: CPU0 CPU1 hande_level_irq(irq X) mask_ack_irq(irq X) handle_IRQ_event(irq X) wake_up(thread_handler) thread handler(irq X) runs finalize_oneshot(irq X) does not unmask due to !(desc->status & IRQ_MASKED) return from irq does not unmask due to (desc->status & IRQ_ONESHOT) This leaves the interrupt line masked forever. The reason for this is the inconsistent handling of the IRQ_MASKED flag. Instead of setting it in the mask function the oneshot support sets the flag after waking up the irq thread. The solution for this is to set/clear the IRQ_MASKED status whenever we mask/unmask an interrupt line. That's the easy part, but that cleanup opens another race: CPU0 CPU1 hande_level_irq(irq) mask_ack_irq(irq) handle_IRQ_event(irq) wake_up(thread_handler) thread handler(irq) runs finalize_oneshot_irq(irq) unmask(irq) irq triggers again handle_level_irq(irq) mask_ack_irq(irq) return from irq due to IRQ_INPROGRESS return from irq does not unmask due to (desc->status & IRQ_ONESHOT) This requires that we synchronize finalize_oneshot_irq() with the primary handler. If IRQ_INPROGESS is set we wait until the primary handler on the other CPU has returned before unmasking the interrupt line again. We probably have never seen that problem because it does not happen on UP and on SMP the irqbalancer protects us by pinning the primary handler and the thread to the same CPU. Reported-by: Lars-Peter Clausen Signed-off-by: Thomas Gleixner Cc: stable@kernel.org

Merge branch 'for-next' into for-linus

2010-03-08T15:55:37Z

Conflicts: Documentation/filesystems/proc.txt arch/arm/mach-u300/include/mach/debug-macro.S drivers/net/qlge/qlge_ethtool.c drivers/net/qlge/qlge_main.c drivers/net/typhoon.c

sparseirq: Use radix_tree instead of ptrs array

2010-02-18T01:27:20Z

Use radix_tree irq_desc_tree instead of irq_desc_ptrs. -v2: according to Eric and cyrill to use radix_tree_lookup_slot and radix_tree_replace_slot Signed-off-by: Yinghai Lu LKML-Reference: <1265793639-15071-32-git-send-email-yinghai@kernel.org> Signed-off-by: H. Peter Anvin

sparseirq: Change irq_desc_ptrs to static

2010-02-18T01:27:03Z

Add replace_irq_desc() instead of poking at the array directly. -v2: remove unneeded boundary check in replace_irq_desc Signed-off-by: Yinghai Lu LKML-Reference: <1265793639-15071-31-git-send-email-yinghai@kernel.org> Signed-off-by: H. Peter Anvin