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Wed, 2 Oct 2019 07:09:45 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 2AE37AF3B; Wed, 2 Oct 2019 11:09:42 +0000 (UTC) Subject: Re: [PATCH 3/3] btrfs: add __pure attribute to functions To: David Sterba , linux-btrfs@vger.kernel.org References: From: Nikolay Borisov Openpgp: preference=signencrypt Autocrypt: addr=nborisov@suse.com; prefer-encrypt=mutual; keydata= mQINBFiKBz4BEADNHZmqwhuN6EAzXj9SpPpH/nSSP8YgfwoOqwrP+JR4pIqRK0AWWeWCSwmZ T7g+RbfPFlmQp+EwFWOtABXlKC54zgSf+uulGwx5JAUFVUIRBmnHOYi/lUiE0yhpnb1KCA7f u/W+DkwGerXqhhe9TvQoGwgCKNfzFPZoM+gZrm+kWv03QLUCr210n4cwaCPJ0Nr9Z3c582xc bCUVbsjt7BN0CFa2BByulrx5xD9sDAYIqfLCcZetAqsTRGxM7LD0kh5WlKzOeAXj5r8DOrU2 GdZS33uKZI/kZJZVytSmZpswDsKhnGzRN1BANGP8sC+WD4eRXajOmNh2HL4P+meO1TlM3GLl EQd2shHFY0qjEo7wxKZI1RyZZ5AgJnSmehrPCyuIyVY210CbMaIKHUIsTqRgY5GaNME24w7h TyyVCy2qAM8fLJ4Vw5bycM/u5xfWm7gyTb9V1TkZ3o1MTrEsrcqFiRrBY94Rs0oQkZvunqia c+NprYSaOG1Cta14o94eMH271Kka/reEwSZkC7T+o9hZ4zi2CcLcY0DXj0qdId7vUKSJjEep c++s8ncFekh1MPhkOgNj8pk17OAESanmDwksmzh1j12lgA5lTFPrJeRNu6/isC2zyZhTwMWs k3LkcTa8ZXxh0RfWAqgx/ogKPk4ZxOXQEZetkEyTFghbRH2BIwARAQABtCNOaWtvbGF5IEJv cmlzb3YgPG5ib3Jpc292QHN1c2UuY29tPokCOAQTAQIAIgUCWIo48QIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQcb6CRuU/KFc0eg/9GLD3wTQz9iZHMFbjiqTCitD7B6dTLV1C ddZVlC8Hm/TophPts1bWZORAmYIihHHI1EIF19+bfIr46pvfTu0yFrJDLOADMDH+Ufzsfy2v HSqqWV/nOSWGXzh8bgg/ncLwrIdEwBQBN9SDS6aqsglagvwFD91UCg/TshLlRxD5BOnuzfzI Leyx2c6YmH7Oa1R4MX9Jo79SaKwdHt2yRN3SochVtxCyafDlZsE/efp21pMiaK1HoCOZTBp5 VzrIP85GATh18pN7YR9CuPxxN0V6IzT7IlhS4Jgj0NXh6vi1DlmKspr+FOevu4RVXqqcNTSS E2rycB2v6cttH21UUdu/0FtMBKh+rv8+yD49FxMYnTi1jwVzr208vDdRU2v7Ij/TxYt/v4O8 V+jNRKy5Fevca/1xroQBICXsNoFLr10X5IjmhAhqIH8Atpz/89ItS3+HWuE4BHB6RRLM0gy8 T7rN6ja+KegOGikp/VTwBlszhvfLhyoyjXI44Tf3oLSFM+8+qG3B7MNBHOt60CQlMkq0fGXd mm4xENl/SSeHsiomdveeq7cNGpHi6i6ntZK33XJLwvyf00PD7tip/GUj0Dic/ZUsoPSTF/mG EpuQiUZs8X2xjK/AS/l3wa4Kz2tlcOKSKpIpna7V1+CMNkNzaCOlbv7QwprAerKYywPCoOSC 7P25Ag0EWIoHPgEQAMiUqvRBZNvPvki34O/dcTodvLSyOmK/MMBDrzN8Cnk302XfnGlW/YAQ csMWISKKSpStc6tmD+2Y0z9WjyRqFr3EGfH1RXSv9Z1vmfPzU42jsdZn667UxrRcVQXUgoKg QYx055Q2FdUeaZSaivoIBD9WtJq/66UPXRRr4H/+Y5FaUZx+gWNGmBT6a0S/GQnHb9g3nonD jmDKGw+YO4P6aEMxyy3k9PstaoiyBXnzQASzdOi39BgWQuZfIQjN0aW+Dm8kOAfT5i/yk59h VV6v3NLHBjHVw9kHli3jwvsizIX9X2W8tb1SefaVxqvqO1132AO8V9CbE1DcVT8fzICvGi42 FoV/k0QOGwq+LmLf0t04Q0csEl+h69ZcqeBSQcIMm/Ir+NorfCr6HjrB6lW7giBkQl6hhomn l1mtDP6MTdbyYzEiBFcwQD4terc7S/8ELRRybWQHQp7sxQM/Lnuhs77MgY/e6c5AVWnMKd/z MKm4ru7A8+8gdHeydrRQSWDaVbfy3Hup0Ia76J9FaolnjB8YLUOJPdhI2vbvNCQ2ipxw3Y3c KhVIpGYqwdvFIiz0Fej7wnJICIrpJs/+XLQHyqcmERn3s/iWwBpeogrx2Lf8AGezqnv9woq7 OSoWlwXDJiUdaqPEB/HmGfqoRRN20jx+OOvuaBMPAPb+aKJyle8zABEBAAGJAh8EGAECAAkF AliKBz4CGwwACgkQcb6CRuU/KFdacg/+M3V3Ti9JYZEiIyVhqs+yHb6NMI1R0kkAmzsGQ1jU zSQUz9AVMR6T7v2fIETTT/f5Oout0+Hi9cY8uLpk8CWno9V9eR/B7Ifs2pAA8lh2nW43FFwp IDiSuDbH6oTLmiGCB206IvSuaQCp1fed8U6yuqGFcnf0ZpJm/sILG2ECdFK9RYnMIaeqlNQm iZicBY2lmlYFBEaMXHoy+K7nbOuizPWdUKoKHq+tmZ3iA+qL5s6Qlm4trH28/fPpFuOmgP8P K+7LpYLNSl1oQUr+WlqilPAuLcCo5Vdl7M7VFLMq4xxY/dY99aZx0ZJQYFx0w/6UkbDdFLzN upT7NIN68lZRucImffiWyN7CjH23X3Tni8bS9ubo7OON68NbPz1YIaYaHmnVQCjDyDXkQoKC R82Vf9mf5slj0Vlpf+/Wpsv/TH8X32ajva37oEQTkWNMsDxyw3aPSps6MaMafcN7k60y2Wk/ TCiLsRHFfMHFY6/lq/c0ZdOsGjgpIK0G0z6et9YU6MaPuKwNY4kBdjPNBwHreucrQVUdqRRm RcxmGC6ohvpqVGfhT48ZPZKZEWM+tZky0mO7bhZYxMXyVjBn4EoNTsXy1et9Y1dU3HVJ8fod 5UqrNrzIQFbdeM0/JqSLrtlTcXKJ7cYFa9ZM2AP7UIN9n1UWxq+OPY9YMOewVfYtL8M= Message-ID: Date: Wed, 2 Oct 2019 14:09:41 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 1.10.19 г. 20:57 ч., David Sterba wrote: > The attribute is more relaxed than const and the functions could > dereference pointers, as long as the observable state is not changed. We > do have such functions, based on -Wsuggest-attribute=pure . > > The visible effects of this patch are negligible, there are differences > in the assembly but hard to summarize. > > Signed-off-by: David Sterba Reviewed-by: Nikolay Borisov one remark: I'm not sure the attribute needs to be duplicated in the declaration and definition. > --- > fs/btrfs/async-thread.c | 6 ++---- > fs/btrfs/async-thread.h | 4 ++-- > fs/btrfs/ctree.c | 2 +- > fs/btrfs/ctree.h | 4 ++-- > fs/btrfs/dev-replace.c | 2 +- > fs/btrfs/dev-replace.h | 2 +- > fs/btrfs/ioctl.c | 2 +- > fs/btrfs/space-info.c | 2 +- > fs/btrfs/space-info.h | 2 +- > 9 files changed, 12 insertions(+), 14 deletions(-) > > diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c > index b97ae1b03417..1d32a07bb2d1 100644 > --- a/fs/btrfs/async-thread.c > +++ b/fs/btrfs/async-thread.c > @@ -53,14 +53,12 @@ struct btrfs_workqueue { > struct __btrfs_workqueue *high; > }; > > -struct btrfs_fs_info * > -btrfs_workqueue_owner(const struct __btrfs_workqueue *wq) > +struct btrfs_fs_info * __pure btrfs_workqueue_owner(const struct __btrfs_workqueue *wq) > { > return wq->fs_info; > } > > -struct btrfs_fs_info * > -btrfs_work_owner(const struct btrfs_work *work) > +struct btrfs_fs_info * __pure btrfs_work_owner(const struct btrfs_work *work) > { > return work->wq->fs_info; > } > diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h > index c5bf2b117c05..a4434301d84d 100644 > --- a/fs/btrfs/async-thread.h > +++ b/fs/btrfs/async-thread.h > @@ -41,8 +41,8 @@ void btrfs_queue_work(struct btrfs_workqueue *wq, > void btrfs_destroy_workqueue(struct btrfs_workqueue *wq); > void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max); > void btrfs_set_work_high_priority(struct btrfs_work *work); > -struct btrfs_fs_info *btrfs_work_owner(const struct btrfs_work *work); > -struct btrfs_fs_info *btrfs_workqueue_owner(const struct __btrfs_workqueue *wq); > +struct btrfs_fs_info * __pure btrfs_work_owner(const struct btrfs_work *work); > +struct btrfs_fs_info * __pure btrfs_workqueue_owner(const struct __btrfs_workqueue *wq); > bool btrfs_workqueue_normal_congested(const struct btrfs_workqueue *wq); > > #endif > diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c > index f2f9cf1149a4..3a4d8e27e565 100644 > --- a/fs/btrfs/ctree.c > +++ b/fs/btrfs/ctree.c > @@ -1538,7 +1538,7 @@ static int comp_keys(const struct btrfs_disk_key *disk, > /* > * same as comp_keys only with two btrfs_key's > */ > -int btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2) > +int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2) > { > if (k1->objectid > k2->objectid) > return 1; > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index 793085770c84..df0f2de69991 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -2511,7 +2511,7 @@ void btrfs_wait_for_snapshot_creation(struct btrfs_root *root); > /* ctree.c */ > int btrfs_bin_search(struct extent_buffer *eb, const struct btrfs_key *key, > int level, int *slot); > -int btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2); > +int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const struct btrfs_key *k2); > int btrfs_previous_item(struct btrfs_root *root, > struct btrfs_path *path, u64 min_objectid, > int type); > @@ -2912,7 +2912,7 @@ long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg); > long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg); > int btrfs_ioctl_get_supported_features(void __user *arg); > void btrfs_sync_inode_flags_to_i_flags(struct inode *inode); > -int btrfs_is_empty_uuid(u8 *uuid); > +int __pure btrfs_is_empty_uuid(u8 *uuid); > int btrfs_defrag_file(struct inode *inode, struct file *file, > struct btrfs_ioctl_defrag_range_args *range, > u64 newer_than, unsigned long max_pages); > diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c > index 48890826b5e6..f639dde2a679 100644 > --- a/fs/btrfs/dev-replace.c > +++ b/fs/btrfs/dev-replace.c > @@ -986,7 +986,7 @@ static int btrfs_dev_replace_kthread(void *data) > return 0; > } > > -int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace) > +int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace) > { > if (!dev_replace->is_valid) > return 0; > diff --git a/fs/btrfs/dev-replace.h b/fs/btrfs/dev-replace.h > index 78c5d8f1adda..60b70dacc299 100644 > --- a/fs/btrfs/dev-replace.h > +++ b/fs/btrfs/dev-replace.h > @@ -17,6 +17,6 @@ void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info, > int btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info); > void btrfs_dev_replace_suspend_for_unmount(struct btrfs_fs_info *fs_info); > int btrfs_resume_dev_replace_async(struct btrfs_fs_info *fs_info); > -int btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace); > +int __pure btrfs_dev_replace_is_ongoing(struct btrfs_dev_replace *dev_replace); > > #endif > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > index de730e56d3f5..55b41d5e7ea9 100644 > --- a/fs/btrfs/ioctl.c > +++ b/fs/btrfs/ioctl.c > @@ -541,7 +541,7 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg) > return 0; > } > > -int btrfs_is_empty_uuid(u8 *uuid) > +int __pure btrfs_is_empty_uuid(u8 *uuid) > { > int i; > > diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c > index 98dc092a905e..f32993efbf61 100644 > --- a/fs/btrfs/space-info.c > +++ b/fs/btrfs/space-info.c > @@ -10,7 +10,7 @@ > #include "transaction.h" > #include "block-group.h" > > -u64 btrfs_space_info_used(struct btrfs_space_info *s_info, > +u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info, > bool may_use_included) > { > ASSERT(s_info); > diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h > index 8867e84aa33d..2d8c811a9792 100644 > --- a/fs/btrfs/space-info.h > +++ b/fs/btrfs/space-info.h > @@ -116,7 +116,7 @@ void btrfs_update_space_info(struct btrfs_fs_info *info, u64 flags, > struct btrfs_space_info **space_info); > struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info, > u64 flags); > -u64 btrfs_space_info_used(struct btrfs_space_info *s_info, > +u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info, > bool may_use_included); > void btrfs_clear_space_info_full(struct btrfs_fs_info *info); > void btrfs_dump_space_info(struct btrfs_fs_info *fs_info, >