Messages in this thread |  | | | From | Jeff Moyer <> | | Subject | Re: [PATCH 02/10] Introduce mm_has_pending_aio() helper | | Date | Tue, 01 Mar 2011 10:40:18 -0500 |
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[added linux-aio@kvack.org to the cc list]
ntl@pobox.com writes:
> From: Nathan Lynch <ntl@pobox.com> > > Support for AIO is on the to-do list, but until that is implemented, > checkpoint will have to fail if a mm_struct has outstanding AIO > contexts. Add a mm_has_pending_aio() helper function for this > purpose.
Just because a process has an io context, doesn't mean that the process has active outstanding requests. So, is this really what you wanted to test?
Cheers, Jeff
> Based on original "check_for_outstanding_aio" patch by Serge Hallyn. > > Signed-off-by: Serge E. Hallyn <serge@hallyn.com> > [ntl: changed name and return type to clearly express semantics] > [ntl: added kerneldoc] > Signed-off-by: Nathan Lynch <ntl@pobox.com> > --- > fs/aio.c | 27 +++++++++++++++++++++++++++ > include/linux/aio.h | 2 ++ > 2 files changed, 29 insertions(+), 0 deletions(-) > > diff --git a/fs/aio.c b/fs/aio.c > index 8c8f6c5..1acbc99 100644 > --- a/fs/aio.c > +++ b/fs/aio.c > @@ -1847,3 +1847,30 @@ SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, > asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout); > return ret; > } > + > +/** > + * mm_has_pending_aio() - check for outstanding AIO operations > + * @mm: The mm_struct to check. > + * > + * Returns true if there is at least one non-dead kioctx on > + * @mm->ioctx_list. Note that the result of this function is > + * unreliable unless the caller has ensured that new requests cannot > + * be submitted against @mm (e.g. through freezing the associated > + * tasks). > + */ > +bool mm_has_pending_aio(struct mm_struct *mm) > +{ > + struct kioctx *ctx; > + struct hlist_node *n; > + bool has_aio = false; > + > + rcu_read_lock(); > + hlist_for_each_entry_rcu(ctx, n, &mm->ioctx_list, list) { > + if (!ctx->dead) { > + has_aio = true; > + break; > + } > + } > + rcu_read_unlock(); > + return has_aio; > +} > diff --git a/include/linux/aio.h b/include/linux/aio.h > index 7a8db41..39d9936 100644 > --- a/include/linux/aio.h > +++ b/include/linux/aio.h > @@ -214,6 +214,7 @@ struct mm_struct; > extern void exit_aio(struct mm_struct *mm); > extern long do_io_submit(aio_context_t ctx_id, long nr, > struct iocb __user *__user *iocbpp, bool compat); > +extern bool mm_has_pending_aio(struct mm_struct *mm); > #else > static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; } > static inline int aio_put_req(struct kiocb *iocb) { return 0; } > @@ -224,6 +225,7 @@ static inline void exit_aio(struct mm_struct *mm) { } > static inline long do_io_submit(aio_context_t ctx_id, long nr, > struct iocb __user * __user *iocbpp, > bool compat) { return 0; } > +static inline bool mm_has_pending_aio(struct mm_struct *mm) { return false; } > #endif /* CONFIG_AIO */ > > static inline struct kiocb *list_kiocb(struct list_head *h)
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