| Message ID | 20240129193512.123145-2-lokeshgidra@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | per-vma locks in userfaultfd | expand |
On Mon, Jan 29, 2024 at 11:35:10AM -0800, Lokesh Gidra wrote: > Moving the struct to userfaultfd_k.h to be accessible from > mm/userfaultfd.c. There are no other changes in the struct. Just a thought, it maybe worth to move all of fs/userfaultfd.c to mm/userfaultfd.c ... > This is required to prepare for using per-vma locks in userfaultfd > operations. > > Signed-off-by: Lokesh Gidra <lokeshgidra@google.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> > --- > fs/userfaultfd.c | 39 ----------------------------------- > include/linux/userfaultfd_k.h | 39 +++++++++++++++++++++++++++++++++++ > 2 files changed, 39 insertions(+), 39 deletions(-) > > diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c > index 05c8e8a05427..58331b83d648 100644 > --- a/fs/userfaultfd.c > +++ b/fs/userfaultfd.c > @@ -50,45 +50,6 @@ static struct ctl_table vm_userfaultfd_table[] = { > > static struct kmem_cache *userfaultfd_ctx_cachep __ro_after_init; > > -/* > - * Start with fault_pending_wqh and fault_wqh so they're more likely > - * to be in the same cacheline. > - * > - * Locking order: > - * fd_wqh.lock > - * fault_pending_wqh.lock > - * fault_wqh.lock > - * event_wqh.lock > - * > - * To avoid deadlocks, IRQs must be disabled when taking any of the above locks, > - * since fd_wqh.lock is taken by aio_poll() while it's holding a lock that's > - * also taken in IRQ context. > - */ > -struct userfaultfd_ctx { > - /* waitqueue head for the pending (i.e. not read) userfaults */ > - wait_queue_head_t fault_pending_wqh; > - /* waitqueue head for the userfaults */ > - wait_queue_head_t fault_wqh; > - /* waitqueue head for the pseudo fd to wakeup poll/read */ > - wait_queue_head_t fd_wqh; > - /* waitqueue head for events */ > - wait_queue_head_t event_wqh; > - /* a refile sequence protected by fault_pending_wqh lock */ > - seqcount_spinlock_t refile_seq; > - /* pseudo fd refcounting */ > - refcount_t refcount; > - /* userfaultfd syscall flags */ > - unsigned int flags; > - /* features requested from the userspace */ > - unsigned int features; > - /* released */ > - bool released; > - /* memory mappings are changing because of non-cooperative event */ > - atomic_t mmap_changing; > - /* mm with one ore more vmas attached to this userfaultfd_ctx */ > - struct mm_struct *mm; > -}; > - > struct userfaultfd_fork_ctx { > struct userfaultfd_ctx *orig; > struct userfaultfd_ctx *new; > diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h > index e4056547fbe6..691d928ee864 100644 > --- a/include/linux/userfaultfd_k.h > +++ b/include/linux/userfaultfd_k.h > @@ -36,6 +36,45 @@ > #define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) > #define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS) > > +/* > + * Start with fault_pending_wqh and fault_wqh so they're more likely > + * to be in the same cacheline. > + * > + * Locking order: > + * fd_wqh.lock > + * fault_pending_wqh.lock > + * fault_wqh.lock > + * event_wqh.lock > + * > + * To avoid deadlocks, IRQs must be disabled when taking any of the above locks, > + * since fd_wqh.lock is taken by aio_poll() while it's holding a lock that's > + * also taken in IRQ context. > + */ > +struct userfaultfd_ctx { > + /* waitqueue head for the pending (i.e. not read) userfaults */ > + wait_queue_head_t fault_pending_wqh; > + /* waitqueue head for the userfaults */ > + wait_queue_head_t fault_wqh; > + /* waitqueue head for the pseudo fd to wakeup poll/read */ > + wait_queue_head_t fd_wqh; > + /* waitqueue head for events */ > + wait_queue_head_t event_wqh; > + /* a refile sequence protected by fault_pending_wqh lock */ > + seqcount_spinlock_t refile_seq; > + /* pseudo fd refcounting */ > + refcount_t refcount; > + /* userfaultfd syscall flags */ > + unsigned int flags; > + /* features requested from the userspace */ > + unsigned int features; > + /* released */ > + bool released; > + /* memory mappings are changing because of non-cooperative event */ > + atomic_t mmap_changing; > + /* mm with one ore more vmas attached to this userfaultfd_ctx */ > + struct mm_struct *mm; > +}; > + > extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason); > > /* A combined operation mode + behavior flags. */ > -- > 2.43.0.429.g432eaa2c6b-goog >
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 05c8e8a05427..58331b83d648 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -50,45 +50,6 @@ static struct ctl_table vm_userfaultfd_table[] = { static struct kmem_cache *userfaultfd_ctx_cachep __ro_after_init; -/* - * Start with fault_pending_wqh and fault_wqh so they're more likely - * to be in the same cacheline. - * - * Locking order: - * fd_wqh.lock - * fault_pending_wqh.lock - * fault_wqh.lock - * event_wqh.lock - * - * To avoid deadlocks, IRQs must be disabled when taking any of the above locks, - * since fd_wqh.lock is taken by aio_poll() while it's holding a lock that's - * also taken in IRQ context. - */ -struct userfaultfd_ctx { - /* waitqueue head for the pending (i.e. not read) userfaults */ - wait_queue_head_t fault_pending_wqh; - /* waitqueue head for the userfaults */ - wait_queue_head_t fault_wqh; - /* waitqueue head for the pseudo fd to wakeup poll/read */ - wait_queue_head_t fd_wqh; - /* waitqueue head for events */ - wait_queue_head_t event_wqh; - /* a refile sequence protected by fault_pending_wqh lock */ - seqcount_spinlock_t refile_seq; - /* pseudo fd refcounting */ - refcount_t refcount; - /* userfaultfd syscall flags */ - unsigned int flags; - /* features requested from the userspace */ - unsigned int features; - /* released */ - bool released; - /* memory mappings are changing because of non-cooperative event */ - atomic_t mmap_changing; - /* mm with one ore more vmas attached to this userfaultfd_ctx */ - struct mm_struct *mm; -}; - struct userfaultfd_fork_ctx { struct userfaultfd_ctx *orig; struct userfaultfd_ctx *new; diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index e4056547fbe6..691d928ee864 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -36,6 +36,45 @@ #define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK) #define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS) +/* + * Start with fault_pending_wqh and fault_wqh so they're more likely + * to be in the same cacheline. + * + * Locking order: + * fd_wqh.lock + * fault_pending_wqh.lock + * fault_wqh.lock + * event_wqh.lock + * + * To avoid deadlocks, IRQs must be disabled when taking any of the above locks, + * since fd_wqh.lock is taken by aio_poll() while it's holding a lock that's + * also taken in IRQ context. + */ +struct userfaultfd_ctx { + /* waitqueue head for the pending (i.e. not read) userfaults */ + wait_queue_head_t fault_pending_wqh; + /* waitqueue head for the userfaults */ + wait_queue_head_t fault_wqh; + /* waitqueue head for the pseudo fd to wakeup poll/read */ + wait_queue_head_t fd_wqh; + /* waitqueue head for events */ + wait_queue_head_t event_wqh; + /* a refile sequence protected by fault_pending_wqh lock */ + seqcount_spinlock_t refile_seq; + /* pseudo fd refcounting */ + refcount_t refcount; + /* userfaultfd syscall flags */ + unsigned int flags; + /* features requested from the userspace */ + unsigned int features; + /* released */ + bool released; + /* memory mappings are changing because of non-cooperative event */ + atomic_t mmap_changing; + /* mm with one ore more vmas attached to this userfaultfd_ctx */ + struct mm_struct *mm; +}; + extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason); /* A combined operation mode + behavior flags. */
Moving the struct to userfaultfd_k.h to be accessible from mm/userfaultfd.c. There are no other changes in the struct. This is required to prepare for using per-vma locks in userfaultfd operations. Signed-off-by: Lokesh Gidra <lokeshgidra@google.com> --- fs/userfaultfd.c | 39 ----------------------------------- include/linux/userfaultfd_k.h | 39 +++++++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+), 39 deletions(-)