From fd2f3b7ee1cf4b5fa77659c5ed4aa3cf5d1b3731 Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Fri, 18 Oct 2013 17:36:16 -0700 Subject: [PATCH 1/2] irq: DocBook/genericirq.tmpl: Correct various typos Typo corrections for DocBook/genericirq.tmpl. Signed-off-by: Randy Dunlap Link: http://lkml.kernel.org/r/5261D400.30400@infradead.org Signed-off-by: Ingo Molnar --- Documentation/DocBook/genericirq.tmpl | 64 +++++++++++++-------------- 1 file changed, 32 insertions(+), 32 deletions(-) diff --git a/Documentation/DocBook/genericirq.tmpl b/Documentation/DocBook/genericirq.tmpl index d16d21b7a3b7..46347f603353 100644 --- a/Documentation/DocBook/genericirq.tmpl +++ b/Documentation/DocBook/genericirq.tmpl @@ -87,7 +87,7 @@ Rationale - The original implementation of interrupt handling in Linux is using + The original implementation of interrupt handling in Linux uses the __do_IRQ() super-handler, which is able to deal with every type of interrupt logic. @@ -111,19 +111,19 @@ - This split implementation of highlevel IRQ handlers allows us to + This split implementation of high-level IRQ handlers allows us to optimize the flow of the interrupt handling for each specific - interrupt type. This reduces complexity in that particular codepath + interrupt type. This reduces complexity in that particular code path and allows the optimized handling of a given type. The original general IRQ implementation used hw_interrupt_type structures and their ->ack(), ->end() [etc.] callbacks to differentiate the flow control in the super-handler. This leads to - a mix of flow logic and lowlevel hardware logic, and it also leads - to unnecessary code duplication: for example in i386, there is a - ioapic_level_irq and a ioapic_edge_irq irq-type which share many - of the lowlevel details but have different flow handling. + a mix of flow logic and low-level hardware logic, and it also leads + to unnecessary code duplication: for example in i386, there is an + ioapic_level_irq and an ioapic_edge_irq IRQ-type which share many + of the low-level details but have different flow handling. A more natural abstraction is the clean separation of the @@ -132,23 +132,23 @@ Analysing a couple of architecture's IRQ subsystem implementations reveals that most of them can use a generic set of 'irq flow' - methods and only need to add the chip level specific code. + methods and only need to add the chip-level specific code. The separation is also valuable for (sub)architectures - which need specific quirks in the irq flow itself but not in the - chip-details - and thus provides a more transparent IRQ subsystem + which need specific quirks in the IRQ flow itself but not in the + chip details - and thus provides a more transparent IRQ subsystem design. - Each interrupt descriptor is assigned its own highlevel flow + Each interrupt descriptor is assigned its own high-level flow handler, which is normally one of the generic - implementations. (This highlevel flow handler implementation also + implementations. (This high-level flow handler implementation also makes it simple to provide demultiplexing handlers which can be found in embedded platforms on various architectures.) The separation makes the generic interrupt handling layer more flexible and extensible. For example, an (sub)architecture can - use a generic irq-flow implementation for 'level type' interrupts + use a generic IRQ-flow implementation for 'level type' interrupts and add a (sub)architecture specific 'edge type' implementation. @@ -172,9 +172,9 @@ There are three main levels of abstraction in the interrupt code: - Highlevel driver API - Highlevel IRQ flow handlers - Chiplevel hardware encapsulation + High-level driver API + High-level IRQ flow handlers + Chip-level hardware encapsulation @@ -189,16 +189,16 @@ which are assigned to this interrupt. - Whenever an interrupt triggers, the lowlevel arch code calls into - the generic interrupt code by calling desc->handle_irq(). - This highlevel IRQ handling function only uses desc->irq_data.chip + Whenever an interrupt triggers, the low-level architecture code calls + into the generic interrupt code by calling desc->handle_irq(). + This high-level IRQ handling function only uses desc->irq_data.chip primitives referenced by the assigned chip descriptor structure. - Highlevel Driver API + High-level Driver API - The highlevel Driver API consists of following functions: + The high-level Driver API consists of following functions: request_irq() free_irq() @@ -216,7 +216,7 @@ - Highlevel IRQ flow handlers + High-level IRQ flow handlers The generic layer provides a set of pre-defined irq-flow methods: @@ -228,7 +228,7 @@ handle_edge_eoi_irq handle_bad_irq - The interrupt flow handlers (either predefined or architecture + The interrupt flow handlers (either pre-defined or architecture specific) are assigned to specific interrupts by the architecture either during bootup or during device initialization. @@ -297,7 +297,7 @@ desc->irq_data.chip->irq_unmask(); handle_fasteoi_irq provides a generic implementation for interrupts, which only need an EOI at the end of - the handler + the handler. The following control flow is implemented (simplified excerpt): @@ -394,7 +394,7 @@ if (desc->irq_data.chip->irq_eoi) The generic functions are intended for 'clean' architectures and chips, which have no platform-specific IRQ handling quirks. If an architecture needs to implement quirks on the 'flow' level then it can do so by - overriding the highlevel irq-flow handler. + overriding the high-level irq-flow handler. @@ -419,9 +419,9 @@ if (desc->irq_data.chip->irq_eoi) - Chiplevel hardware encapsulation + Chip-level hardware encapsulation - The chip level hardware descriptor structure irq_chip + The chip-level hardware descriptor structure irq_chip contains all the direct chip relevant functions, which can be utilized by the irq flow implementations. @@ -429,14 +429,14 @@ if (desc->irq_data.chip->irq_eoi) irq_mask_ack() - Optional, recommended for performance irq_mask() irq_unmask() - irq_eoi() - Optional, required for eoi flow handlers + irq_eoi() - Optional, required for EOI flow handlers irq_retrigger() - Optional irq_set_type() - Optional irq_set_wake() - Optional These primitives are strictly intended to mean what they say: ack means ACK, masking means masking of an IRQ line, etc. It is up to the flow - handler(s) to use these basic units of lowlevel functionality. + handler(s) to use these basic units of low-level functionality. @@ -445,7 +445,7 @@ if (desc->irq_data.chip->irq_eoi) __do_IRQ entry point The original implementation __do_IRQ() was an alternative entry - point for all types of interrupts. It not longer exists. + point for all types of interrupts. It no longer exists. This handler turned out to be not suitable for all @@ -468,11 +468,11 @@ if (desc->irq_data.chip->irq_eoi) Generic interrupt chip - To avoid copies of identical implementations of irq chips the + To avoid copies of identical implementations of IRQ chips the core provides a configurable generic interrupt chip implementation. Developers should check carefuly whether the generic chip fits their needs before implementing the same - functionality slightly different themself. + functionality slightly differently themselves. !Ekernel/irq/generic-chip.c From bbfe65c219c638e19f1da5adab1005b2d68ca810 Mon Sep 17 00:00:00 2001 From: Thomas Pfaff Date: Fri, 11 Oct 2013 13:00:40 +0200 Subject: [PATCH 2/2] genirq: Set the irq thread policy without checking CAP_SYS_NICE In commit ee23871389 ("genirq: Set irq thread to RT priority on creation") we moved the assigment of the thread's priority from the thread's function into __setup_irq(). That function may run in user context for instance if the user opens an UART node and then driver calls requests in the ->open() callback. That user may not have CAP_SYS_NICE and so the irq thread won't run with the SCHED_OTHER policy. This patch uses sched_setscheduler_nocheck() so we omit the CAP_SYS_NICE check which is otherwise required for the SCHED_OTHER policy. [bigeasy: Rewrite the changelog] Signed-off-by: Thomas Pfaff Cc: Ivo Sieben Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1381489240-29626-1-git-send-email-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 514bcfd855a8..3e59f951d42f 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -956,7 +956,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) goto out_mput; } - sched_setscheduler(t, SCHED_FIFO, ¶m); + sched_setscheduler_nocheck(t, SCHED_FIFO, ¶m); /* * We keep the reference to the task struct even if