On Tue, 26 Oct 2021, Michal Hocko wrote:
> From: Michal Hocko <mhocko@xxxxxxxx>
>
> A support for GFP_NO{FS,IO} and __GFP_NOFAIL has been implemented
> by previous patches so we can allow the support for kvmalloc. This
> will allow some external users to simplify or completely remove
> their helpers.
>
> GFP_NOWAIT semantic hasn't been supported so far but it hasn't been
> explicitly documented so let's add a note about that.
>
> ceph_kvmalloc is the first helper to be dropped and changed to
> kvmalloc.
>
> Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
> ---
> include/linux/ceph/libceph.h | 1 -
> mm/util.c | 15 ++++-----------
> net/ceph/buffer.c | 4 ++--
> net/ceph/ceph_common.c | 27 ---------------------------
> net/ceph/crypto.c | 2 +-
> net/ceph/messenger.c | 2 +-
> net/ceph/messenger_v2.c | 2 +-
> net/ceph/osdmap.c | 12 ++++++------
> 8 files changed, 15 insertions(+), 50 deletions(-)
>
> diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
> index 409d8c29bc4f..309acbcb5a8a 100644
> --- a/include/linux/ceph/libceph.h
> +++ b/include/linux/ceph/libceph.h
> @@ -295,7 +295,6 @@ extern bool libceph_compatible(void *data);
>
> extern const char *ceph_msg_type_name(int type);
> extern int ceph_check_fsid(struct ceph_client *client, struct ceph_fsid *fsid);
> -extern void *ceph_kvmalloc(size_t size, gfp_t flags);
>
> struct fs_parameter;
> struct fc_log;
> diff --git a/mm/util.c b/mm/util.c
> index bacabe446906..fdec6b4b1267 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -549,13 +549,10 @@ EXPORT_SYMBOL(vm_mmap);
> * Uses kmalloc to get the memory but if the allocation fails then falls back
> * to the vmalloc allocator. Use kvfree for freeing the memory.
> *
> - * Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported.
> + * Reclaim modifiers - __GFP_NORETRY and GFP_NOWAIT are not supported.
GFP_NOWAIT is not a modifier. It is a base value that can be modified.
I think you mean that
__GFP_NORETRY is not supported and __GFP_DIRECT_RECLAIM is required
But I really cannot see why either of these statements are true.
Before your patch, __GFP_NORETRY would have forced use of kmalloc, so
that would mean it isn't really supported. But that doesn't happen any more.
Thanks,
NeilBrown
