| Message ID | 20201022212228.15703-2-willy@infradead.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | Make block_read_full_page synchronous | expand |
On Thu, Oct 22, 2020 at 10:22:23PM +0100, Matthew Wilcox (Oracle) wrote: > This new data structure allows a task to wait for N things to complete. > Usually the submitting task will handle cleanup, but if it is killed, > the last completer will take care of it. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> > --- > block/blk-core.c | 61 +++++++++++++++++++++++++++++++++++++++++++++ > include/linux/bio.h | 11 ++++++++ > 2 files changed, 72 insertions(+) > > diff --git a/block/blk-core.c b/block/blk-core.c > index 10c08ac50697..2892246f2176 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -1900,6 +1900,67 @@ void blk_io_schedule(void) > } > EXPORT_SYMBOL_GPL(blk_io_schedule); > > +void blk_completion_init(struct blk_completion *cmpl, int n) > +{ > + spin_lock_init(&cmpl->cmpl_lock); > + cmpl->cmpl_count = n; > + cmpl->cmpl_task = current; > + cmpl->cmpl_status = BLK_STS_OK; > +} > + > +int blk_completion_sub(struct blk_completion *cmpl, blk_status_t status, int n) This needs documentation. e.g. to explain what 'n' is. > +int blk_completion_wait_killable(struct blk_completion *cmpl) > +{ > + int err = 0; > + > + for (;;) { > + set_current_state(TASK_KILLABLE); > + spin_lock_bh(&cmpl->cmpl_lock); > + if (cmpl->cmpl_count == 0) > + break; > + spin_unlock_bh(&cmpl->cmpl_lock); > + blk_io_schedule(); > + if (fatal_signal_pending(current)) { > + spin_lock_bh(&cmpl->cmpl_lock); > + cmpl->cmpl_task = NULL; > + if (cmpl->cmpl_count != 0) { > + spin_unlock_bh(&cmpl->cmpl_lock); > + cmpl = NULL; > + } > + err = -ERESTARTSYS; > + break; > + } > + } > + set_current_state(TASK_RUNNING); > + if (cmpl) { > + spin_unlock_bh(&cmpl->cmpl_lock); > + err = blk_status_to_errno(cmpl->cmpl_status); > + kfree(cmpl); > + } > + > + return err; > +} What are the life time rules for cmpl? Who frees it in the case of a fatal signal?
diff --git a/block/blk-core.c b/block/blk-core.c index 10c08ac50697..2892246f2176 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1900,6 +1900,67 @@ void blk_io_schedule(void) } EXPORT_SYMBOL_GPL(blk_io_schedule); +void blk_completion_init(struct blk_completion *cmpl, int n) +{ + spin_lock_init(&cmpl->cmpl_lock); + cmpl->cmpl_count = n; + cmpl->cmpl_task = current; + cmpl->cmpl_status = BLK_STS_OK; +} + +int blk_completion_sub(struct blk_completion *cmpl, blk_status_t status, int n) +{ + int ret = 0; + + spin_lock_bh(&cmpl->cmpl_lock); + if (cmpl->cmpl_status == BLK_STS_OK && status != BLK_STS_OK) + cmpl->cmpl_status = status; + cmpl->cmpl_count -= n; + BUG_ON(cmpl->cmpl_count < 0); + if (cmpl->cmpl_count == 0) { + if (cmpl->cmpl_task) + wake_up_process(cmpl->cmpl_task); + else + ret = -EINTR; + } + spin_unlock_bh(&cmpl->cmpl_lock); + if (ret < 0) + kfree(cmpl); + return ret; +} + +int blk_completion_wait_killable(struct blk_completion *cmpl) +{ + int err = 0; + + for (;;) { + set_current_state(TASK_KILLABLE); + spin_lock_bh(&cmpl->cmpl_lock); + if (cmpl->cmpl_count == 0) + break; + spin_unlock_bh(&cmpl->cmpl_lock); + blk_io_schedule(); + if (fatal_signal_pending(current)) { + spin_lock_bh(&cmpl->cmpl_lock); + cmpl->cmpl_task = NULL; + if (cmpl->cmpl_count != 0) { + spin_unlock_bh(&cmpl->cmpl_lock); + cmpl = NULL; + } + err = -ERESTARTSYS; + break; + } + } + set_current_state(TASK_RUNNING); + if (cmpl) { + spin_unlock_bh(&cmpl->cmpl_lock); + err = blk_status_to_errno(cmpl->cmpl_status); + kfree(cmpl); + } + + return err; +} + int __init blk_dev_init(void) { BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS)); diff --git a/include/linux/bio.h b/include/linux/bio.h index f254bc79bb3a..0bde05f5548c 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -814,4 +814,15 @@ static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb) bio->bi_opf |= REQ_NOWAIT; } +struct blk_completion { + struct task_struct *cmpl_task; + spinlock_t cmpl_lock; + int cmpl_count; + blk_status_t cmpl_status; +}; + +void blk_completion_init(struct blk_completion *, int n); +int blk_completion_sub(struct blk_completion *, blk_status_t status, int n); +int blk_completion_wait_killable(struct blk_completion *); + #endif /* __LINUX_BIO_H */
This new data structure allows a task to wait for N things to complete. Usually the submitting task will handle cleanup, but if it is killed, the last completer will take care of it. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> --- block/blk-core.c | 61 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/bio.h | 11 ++++++++ 2 files changed, 72 insertions(+)