Re: [PATCH 01/13] irq_poll: make blk-iopoll available outside the block layer

[Bart Van Assche]

On 12/07/2015 12:51 PM, Christoph Hellwig wrote:

-enum {
-   IOPOLL_F_SCHED  = 0,
-   IOPOLL_F_DISABLE= 1,
-};


[ ... ]


+enum {
+   IRQ_POLL_F_SCHED= 0,
+   IRQ_POLL_F_DISABLE  = 1,
+};


A nitpick: the values of these constants were aligned in the original 
code but no longer in the new code. Whether or not this gets addressed:


Reviewed-by: Bart Van Assche 
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[PATCH 01/13] irq_poll: make blk-iopoll available outside the block layer

[Christoph Hellwig]

The new name is irq_poll as iopoll is already taken.  Better suggestions
welcome.

Signed-off-by: Christoph Hellwig 
---
 Documentation/kernel-per-CPU-kthreads.txt |   2 +-
 block/Makefile|   2 +-
 block/blk-iopoll.c| 224 --
 drivers/scsi/Kconfig  |   1 +
 drivers/scsi/be2iscsi/Kconfig |   1 +
 drivers/scsi/be2iscsi/be.h|   4 +-
 drivers/scsi/be2iscsi/be_iscsi.c  |   4 +-
 drivers/scsi/be2iscsi/be_main.c   |  24 ++--
 drivers/scsi/ipr.c|  28 ++--
 drivers/scsi/ipr.h|   4 +-
 include/linux/blk-iopoll.h|  46 --
 include/linux/interrupt.h |   2 +-
 include/linux/irq_poll.h  |  46 ++
 include/trace/events/irq.h|   2 +-
 lib/Kconfig   |   5 +
 lib/Makefile  |   1 +
 lib/irq_poll.c| 221 +
 tools/lib/traceevent/event-parse.c|   2 +-
 tools/perf/util/trace-event-parse.c   |   2 +-
 19 files changed, 313 insertions(+), 308 deletions(-)
 delete mode 100644 block/blk-iopoll.c
 delete mode 100644 include/linux/blk-iopoll.h
 create mode 100644 include/linux/irq_poll.h
 create mode 100644 lib/irq_poll.c

diff --git a/Documentation/kernel-per-CPU-kthreads.txt 
b/Documentation/kernel-per-CPU-kthreads.txt
index f4cbfe0..edec3a3 100644
--- a/Documentation/kernel-per-CPU-kthreads.txt
+++ b/Documentation/kernel-per-CPU-kthreads.txt
@@ -90,7 +90,7 @@ BLOCK_SOFTIRQ:  Do all of the following:
from being initiated from tasks that might run on the CPU to
be de-jittered.  (It is OK to force this CPU offline and then
bring it back online before you start your application.)
-BLOCK_IOPOLL_SOFTIRQ:  Do all of the following:
+IRQ_POLL_SOFTIRQ:  Do all of the following:
 1. Force block-device interrupts onto some other CPU.
 2. Initiate any block I/O and block-I/O polling on other CPUs.
 3. Once your application has started, prevent CPU-hotplug operations
diff --git a/block/Makefile b/block/Makefile
index 00ecc97..e850474 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -5,7 +5,7 @@
 obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-tag.o blk-sysfs.o \
blk-flush.o blk-settings.o blk-ioc.o blk-map.o \
blk-exec.o blk-merge.o blk-softirq.o blk-timeout.o \
-   blk-iopoll.o blk-lib.o blk-mq.o blk-mq-tag.o \
+   blk-lib.o blk-mq.o blk-mq-tag.o \
blk-mq-sysfs.o blk-mq-cpu.o blk-mq-cpumap.o ioctl.o \
genhd.o scsi_ioctl.o partition-generic.o ioprio.o \
partitions/
diff --git a/block/blk-iopoll.c b/block/blk-iopoll.c
deleted file mode 100644
index 0736729..000
--- a/block/blk-iopoll.c
+++ /dev/null
@@ -1,224 +0,0 @@
-/*
- * Functions related to interrupt-poll handling in the block layer. This
- * is similar to NAPI for network devices.
- */
-#include 
-#include 
-#include 
-#include 
-#include 
-#include 
-#include 
-#include 
-#include 
-
-#include "blk.h"
-
-static unsigned int blk_iopoll_budget __read_mostly = 256;
-
-static DEFINE_PER_CPU(struct list_head, blk_cpu_iopoll);
-
-/**
- * blk_iopoll_sched - Schedule a run of the iopoll handler
- * @iop:  The parent iopoll structure
- *
- * Description:
- * Add this blk_iopoll structure to the pending poll list and trigger the
- * raise of the blk iopoll softirq. The driver must already have gotten a
- * successful return from blk_iopoll_sched_prep() before calling this.
- **/
-void blk_iopoll_sched(struct blk_iopoll *iop)
-{
-   unsigned long flags;
-
-   local_irq_save(flags);
-   list_add_tail(>list, this_cpu_ptr(_cpu_iopoll));
-   __raise_softirq_irqoff(BLOCK_IOPOLL_SOFTIRQ);
-   local_irq_restore(flags);
-}
-EXPORT_SYMBOL(blk_iopoll_sched);
-
-/**
- * __blk_iopoll_complete - Mark this @iop as un-polled again
- * @iop:  The parent iopoll structure
- *
- * Description:
- * See blk_iopoll_complete(). This function must be called with interrupts
- * disabled.
- **/
-void __blk_iopoll_complete(struct blk_iopoll *iop)
-{
-   list_del(>list);
-   smp_mb__before_atomic();
-   clear_bit_unlock(IOPOLL_F_SCHED, >state);
-}
-EXPORT_SYMBOL(__blk_iopoll_complete);
-
-/**
- * blk_iopoll_complete - Mark this @iop as un-polled again
- * @iop:  The parent iopoll structure
- *
- * Description:
- * If a driver consumes less than the assigned budget in its run of the
- * iopoll handler, it'll end the polled mode by calling this function. The
- * iopoll handler will not be invoked again before blk_iopoll_sched_prep()
- * is called.
- **/
-void blk_iopoll_complete(struct blk_iopoll *iop)
-{
-   unsigned long flags;
-
-