| Message ID | 20221005032257.80681-2-kch@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: add and use init tagset helper | expand |
On 10/5/22 12:22, Chaitanya Kulkarni wrote: > Add and use the helper to initialize the common fields of the tag_set > such as blk_mq_ops, number of h/w queues, queue depth, command size, > numa_node, timeout, BLK_MQ_F_XXX flags, driver data. This initialization > is spread all over the block drivers. This avoids the code repetation of > the inialization code of the tag set in current block drivers and any s/inialization/initialization s/repetation/repetition > future ones. > > Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com> > --- > block/blk-mq.c | 20 ++++++++++++++++++++ > drivers/block/null_blk/main.c | 10 +++------- > include/linux/blk-mq.h | 5 +++++ > 3 files changed, 28 insertions(+), 7 deletions(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 8070b6c10e8d..e3a8dd81bbe2 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -4341,6 +4341,26 @@ static int blk_mq_alloc_tag_set_tags(struct blk_mq_tag_set *set, > return blk_mq_realloc_tag_set_tags(set, 0, new_nr_hw_queues); > } > > +void blk_mq_init_tag_set(struct blk_mq_tag_set *set, > + const struct blk_mq_ops *ops, unsigned int nr_hw_queues, > + unsigned int queue_depth, unsigned int cmd_size, int numa_node, > + unsigned int timeout, unsigned int flags, void *driver_data) That is an awful lot of arguments... I would be tempted to say pack all these into a struct but then that would kind of negate this patchset goal. Using a function with that many arguments will be error prone, and hard to review... Not a fan. > +{ > + if (!set) > + return; > + > + set->ops = ops; > + set->nr_hw_queues = nr_hw_queues; > + set->queue_depth = queue_depth; > + set->cmd_size = cmd_size; > + set->numa_node = numa_node; > + set->timeout = timeout; > + set->flags = flags; > + set->driver_data = driver_data; > +} > + No blank line here. > +EXPORT_SYMBOL_GPL(blk_mq_init_tag_set); > + > /* > * Alloc a tag set to be associated with one or more request queues. > * May fail with EINVAL for various error conditions. May adjust the > diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c > index 1f154f92f4c2..0b07aab980c4 100644 > --- a/drivers/block/null_blk/main.c > +++ b/drivers/block/null_blk/main.c > @@ -1926,13 +1926,9 @@ static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set) > flags |= BLK_MQ_F_BLOCKING; > } > > - set->ops = &null_mq_ops; > - set->cmd_size = sizeof(struct nullb_cmd); > - set->flags = flags; > - set->driver_data = nullb; > - set->nr_hw_queues = hw_queues; > - set->queue_depth = queue_depth; > - set->numa_node = numa_node; > + blk_mq_init_tag_set(set, &null_mq_ops, hw_queues, queue_depth, > + sizeof(struct nullb_cmd), numa_node, 0, flags, nullb); > + > if (poll_queues) { > set->nr_hw_queues += poll_queues; > set->nr_maps = 3; > diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h > index ba18e9bdb799..06087a8e4398 100644 > --- a/include/linux/blk-mq.h > +++ b/include/linux/blk-mq.h > @@ -708,6 +708,11 @@ int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, > struct request_queue *q); > void blk_mq_destroy_queue(struct request_queue *); > > + No need for the extra whiteline. > +void blk_mq_init_tag_set(struct blk_mq_tag_set *set, > + const struct blk_mq_ops *ops, unsigned int nr_hw_queues, > + unsigned int queue_depth, unsigned int cmd_size, int numa_node, > + unsigned int timeout, unsigned int flags, void *driver_data); > int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set); > int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set *set, > const struct blk_mq_ops *ops, unsigned int queue_depth,
On Wed, 5 Oct 2022 at 07:11, Damien Le Moal <damien.lemoal@opensource.wdc.com> wrote: > > On 10/5/22 12:22, Chaitanya Kulkarni wrote: > > Add and use the helper to initialize the common fields of the tag_set > > such as blk_mq_ops, number of h/w queues, queue depth, command size, > > numa_node, timeout, BLK_MQ_F_XXX flags, driver data. This initialization > > is spread all over the block drivers. This avoids the code repetation of > > the inialization code of the tag set in current block drivers and any > > s/inialization/initialization > s/repetation/repetition > > > future ones. > > > > Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com> > > --- > > block/blk-mq.c | 20 ++++++++++++++++++++ > > drivers/block/null_blk/main.c | 10 +++------- > > include/linux/blk-mq.h | 5 +++++ > > 3 files changed, 28 insertions(+), 7 deletions(-) > > > > diff --git a/block/blk-mq.c b/block/blk-mq.c > > index 8070b6c10e8d..e3a8dd81bbe2 100644 > > --- a/block/blk-mq.c > > +++ b/block/blk-mq.c > > @@ -4341,6 +4341,26 @@ static int blk_mq_alloc_tag_set_tags(struct blk_mq_tag_set *set, > > return blk_mq_realloc_tag_set_tags(set, 0, new_nr_hw_queues); > > } > > > > +void blk_mq_init_tag_set(struct blk_mq_tag_set *set, > > + const struct blk_mq_ops *ops, unsigned int nr_hw_queues, > > + unsigned int queue_depth, unsigned int cmd_size, int numa_node, > > + unsigned int timeout, unsigned int flags, void *driver_data) > > That is an awful lot of arguments... I would be tempted to say pack all > these into a struct but then that would kind of negate this patchset goal. > Using a function with that many arguments will be error prone, and hard to > review... Not a fan. I completely agree. But there is also another problem going down this route. If/when we realize that there is another parameter needed in the blk_mq_tag_set. Today that's quite easy to add (assuming the parameter can be optional), without changing the blk_mq_init_tag_set() interface. > > > +{ > > + if (!set) > > + return; > > + > > + set->ops = ops; > > + set->nr_hw_queues = nr_hw_queues; > > + set->queue_depth = queue_depth; > > + set->cmd_size = cmd_size; > > + set->numa_node = numa_node; > > + set->timeout = timeout; > > + set->flags = flags; > > + set->driver_data = driver_data; > > +} > > + > [...] Kind regards Uffe
On 10/5/22 02:47, Ulf Hansson wrote: > On Wed, 5 Oct 2022 at 07:11, Damien Le Moal <damien.lemoal@opensource.wdc.com> wrote: >> On 10/5/22 12:22, Chaitanya Kulkarni wrote: >>> +void blk_mq_init_tag_set(struct blk_mq_tag_set *set, >>> + const struct blk_mq_ops *ops, unsigned int nr_hw_queues, >>> + unsigned int queue_depth, unsigned int cmd_size, int numa_node, >>> + unsigned int timeout, unsigned int flags, void *driver_data) >> >> That is an awful lot of arguments... I would be tempted to say pack all >> these into a struct but then that would kind of negate this patchset goal. >> Using a function with that many arguments will be error prone, and hard to >> review... Not a fan. > > I completely agree. > > But there is also another problem going down this route. If/when we > realize that there is another parameter needed in the blk_mq_tag_set. > Today that's quite easy to add (assuming the parameter can be > optional), without changing the blk_mq_init_tag_set() interface. Hi Chaitanya, Please consider to drop the entire patch series. In addition to the disadvantages mentioned above I'd like to mention the following disadvantages: * Replacing named member assignments with positional arguments in a function call makes code harder to read and harder to verify. * This patch series makes tree-wide changes without improving the code in a substantial way. Thanks, Bart.
diff --git a/block/blk-mq.c b/block/blk-mq.c index 8070b6c10e8d..e3a8dd81bbe2 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -4341,6 +4341,26 @@ static int blk_mq_alloc_tag_set_tags(struct blk_mq_tag_set *set, return blk_mq_realloc_tag_set_tags(set, 0, new_nr_hw_queues); } +void blk_mq_init_tag_set(struct blk_mq_tag_set *set, + const struct blk_mq_ops *ops, unsigned int nr_hw_queues, + unsigned int queue_depth, unsigned int cmd_size, int numa_node, + unsigned int timeout, unsigned int flags, void *driver_data) +{ + if (!set) + return; + + set->ops = ops; + set->nr_hw_queues = nr_hw_queues; + set->queue_depth = queue_depth; + set->cmd_size = cmd_size; + set->numa_node = numa_node; + set->timeout = timeout; + set->flags = flags; + set->driver_data = driver_data; +} + +EXPORT_SYMBOL_GPL(blk_mq_init_tag_set); + /* * Alloc a tag set to be associated with one or more request queues. * May fail with EINVAL for various error conditions. May adjust the diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c index 1f154f92f4c2..0b07aab980c4 100644 --- a/drivers/block/null_blk/main.c +++ b/drivers/block/null_blk/main.c @@ -1926,13 +1926,9 @@ static int null_init_tag_set(struct nullb *nullb, struct blk_mq_tag_set *set) flags |= BLK_MQ_F_BLOCKING; } - set->ops = &null_mq_ops; - set->cmd_size = sizeof(struct nullb_cmd); - set->flags = flags; - set->driver_data = nullb; - set->nr_hw_queues = hw_queues; - set->queue_depth = queue_depth; - set->numa_node = numa_node; + blk_mq_init_tag_set(set, &null_mq_ops, hw_queues, queue_depth, + sizeof(struct nullb_cmd), numa_node, 0, flags, nullb); + if (poll_queues) { set->nr_hw_queues += poll_queues; set->nr_maps = 3; diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index ba18e9bdb799..06087a8e4398 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -708,6 +708,11 @@ int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, struct request_queue *q); void blk_mq_destroy_queue(struct request_queue *); + +void blk_mq_init_tag_set(struct blk_mq_tag_set *set, + const struct blk_mq_ops *ops, unsigned int nr_hw_queues, + unsigned int queue_depth, unsigned int cmd_size, int numa_node, + unsigned int timeout, unsigned int flags, void *driver_data); int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set); int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set *set, const struct blk_mq_ops *ops, unsigned int queue_depth,
Add and use the helper to initialize the common fields of the tag_set such as blk_mq_ops, number of h/w queues, queue depth, command size, numa_node, timeout, BLK_MQ_F_XXX flags, driver data. This initialization is spread all over the block drivers. This avoids the code repetation of the inialization code of the tag set in current block drivers and any future ones. Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com> --- block/blk-mq.c | 20 ++++++++++++++++++++ drivers/block/null_blk/main.c | 10 +++------- include/linux/blk-mq.h | 5 +++++ 3 files changed, 28 insertions(+), 7 deletions(-)