From: Anand Jain <anand.jain@oracle.com>
To: Goldwyn Rodrigues <rgoldwyn@suse.de>, linux-btrfs@vger.kernel.org
Cc: Goldwyn Rodrigues <rgoldwyn@suse.com>
Subject: Re: [PATCH 3/7] btrfs: Allocate btrfs_ioctl_get_subvol_info_args on stack
Date: Wed, 28 Jul 2021 13:59:44 +0800 [thread overview]
Message-ID: <65c2e16a-70a2-c29e-b5b6-70a8118f7665@oracle.com> (raw)
In-Reply-To: <2200f9340973d627ee304ac4470f5921061266f9.1627418762.git.rgoldwyn@suse.com>
On 28/07/2021 05:17, Goldwyn Rodrigues wrote:
> From: Goldwyn Rodrigues <rgoldwyn@suse.com>
>
> Instead of using kmalloc() to allocate btrfs_ioctl_get_subvol_info_args,
> allocate btrfs_ioctl_get_subvol_info_args on stack.
>
> sizeof(btrfs_ioctl_get_subvol_info_args) = 504
>
> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Looks good.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
> ---
> fs/btrfs/ioctl.c | 55 +++++++++++++++++++++---------------------------
> 1 file changed, 24 insertions(+), 31 deletions(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 0ba98e08a029..90b134b5a653 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -2681,7 +2681,7 @@ static int btrfs_ioctl_ino_lookup_user(struct file *file, void __user *argp)
> /* Get the subvolume information in BTRFS_ROOT_ITEM and BTRFS_ROOT_BACKREF */
> static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
> {
> - struct btrfs_ioctl_get_subvol_info_args *subvol_info;
> + struct btrfs_ioctl_get_subvol_info_args subvol_info = {0};
> struct btrfs_fs_info *fs_info;
> struct btrfs_root *root;
> struct btrfs_path *path;
> @@ -2699,12 +2699,6 @@ static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
> if (!path)
> return -ENOMEM;
>
> - subvol_info = kzalloc(sizeof(*subvol_info), GFP_KERNEL);
> - if (!subvol_info) {
> - btrfs_free_path(path);
> - return -ENOMEM;
> - }
> -
> inode = file_inode(file);
> fs_info = BTRFS_I(inode)->root->fs_info;
>
> @@ -2717,32 +2711,32 @@ static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
> }
> root_item = &root->root_item;
>
> - subvol_info->treeid = key.objectid;
> + subvol_info.treeid = key.objectid;
>
> - subvol_info->generation = btrfs_root_generation(root_item);
> - subvol_info->flags = btrfs_root_flags(root_item);
> + subvol_info.generation = btrfs_root_generation(root_item);
> + subvol_info.flags = btrfs_root_flags(root_item);
>
> - memcpy(subvol_info->uuid, root_item->uuid, BTRFS_UUID_SIZE);
> - memcpy(subvol_info->parent_uuid, root_item->parent_uuid,
> + memcpy(subvol_info.uuid, root_item->uuid, BTRFS_UUID_SIZE);
> + memcpy(subvol_info.parent_uuid, root_item->parent_uuid,
> BTRFS_UUID_SIZE);
> - memcpy(subvol_info->received_uuid, root_item->received_uuid,
> + memcpy(subvol_info.received_uuid, root_item->received_uuid,
> BTRFS_UUID_SIZE);
>
> - subvol_info->ctransid = btrfs_root_ctransid(root_item);
> - subvol_info->ctime.sec = btrfs_stack_timespec_sec(&root_item->ctime);
> - subvol_info->ctime.nsec = btrfs_stack_timespec_nsec(&root_item->ctime);
> + subvol_info.ctransid = btrfs_root_ctransid(root_item);
> + subvol_info.ctime.sec = btrfs_stack_timespec_sec(&root_item->ctime);
> + subvol_info.ctime.nsec = btrfs_stack_timespec_nsec(&root_item->ctime);
>
> - subvol_info->otransid = btrfs_root_otransid(root_item);
> - subvol_info->otime.sec = btrfs_stack_timespec_sec(&root_item->otime);
> - subvol_info->otime.nsec = btrfs_stack_timespec_nsec(&root_item->otime);
> + subvol_info.otransid = btrfs_root_otransid(root_item);
> + subvol_info.otime.sec = btrfs_stack_timespec_sec(&root_item->otime);
> + subvol_info.otime.nsec = btrfs_stack_timespec_nsec(&root_item->otime);
>
> - subvol_info->stransid = btrfs_root_stransid(root_item);
> - subvol_info->stime.sec = btrfs_stack_timespec_sec(&root_item->stime);
> - subvol_info->stime.nsec = btrfs_stack_timespec_nsec(&root_item->stime);
> + subvol_info.stransid = btrfs_root_stransid(root_item);
> + subvol_info.stime.sec = btrfs_stack_timespec_sec(&root_item->stime);
> + subvol_info.stime.nsec = btrfs_stack_timespec_nsec(&root_item->stime);
>
> - subvol_info->rtransid = btrfs_root_rtransid(root_item);
> - subvol_info->rtime.sec = btrfs_stack_timespec_sec(&root_item->rtime);
> - subvol_info->rtime.nsec = btrfs_stack_timespec_nsec(&root_item->rtime);
> + subvol_info.rtransid = btrfs_root_rtransid(root_item);
> + subvol_info.rtime.sec = btrfs_stack_timespec_sec(&root_item->rtime);
> + subvol_info.rtime.nsec = btrfs_stack_timespec_nsec(&root_item->rtime);
>
> if (key.objectid != BTRFS_FS_TREE_OBJECTID) {
> /* Search root tree for ROOT_BACKREF of this subvolume */
> @@ -2765,18 +2759,18 @@ static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
> leaf = path->nodes[0];
> slot = path->slots[0];
> btrfs_item_key_to_cpu(leaf, &key, slot);
> - if (key.objectid == subvol_info->treeid &&
> + if (key.objectid == subvol_info.treeid &&
> key.type == BTRFS_ROOT_BACKREF_KEY) {
> - subvol_info->parent_id = key.offset;
> + subvol_info.parent_id = key.offset;
>
> rref = btrfs_item_ptr(leaf, slot, struct btrfs_root_ref);
> - subvol_info->dirid = btrfs_root_ref_dirid(leaf, rref);
> + subvol_info.dirid = btrfs_root_ref_dirid(leaf, rref);
>
> item_off = btrfs_item_ptr_offset(leaf, slot)
> + sizeof(struct btrfs_root_ref);
> item_len = btrfs_item_size_nr(leaf, slot)
> - sizeof(struct btrfs_root_ref);
> - read_extent_buffer(leaf, subvol_info->name,
> + read_extent_buffer(leaf, subvol_info.name,
> item_off, item_len);
> } else {
> ret = -ENOENT;
> @@ -2784,14 +2778,13 @@ static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
> }
> }
>
> - if (copy_to_user(argp, subvol_info, sizeof(*subvol_info)))
> + if (copy_to_user(argp, &subvol_info, sizeof(subvol_info)))
> ret = -EFAULT;
>
> out:
> btrfs_put_root(root);
> out_free:
> btrfs_free_path(path);
> - kfree(subvol_info);
> return ret;
> }
>
>
next prev parent reply other threads:[~2021-07-28 6:00 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-28 12:51 [PATCH 0/7] Change allocation from kmalloc() to stack Goldwyn Rodrigues
2021-07-27 21:17 ` [PATCH 1/7] btrfs: Allocate walk_control on stack Goldwyn Rodrigues
2021-07-28 5:11 ` Anand Jain
2021-07-28 5:25 ` Anand Jain
2021-07-28 11:08 ` David Sterba
2021-07-27 21:17 ` [PATCH 2/7] btrfs: Allocate file_ra_state " Goldwyn Rodrigues
2021-07-28 5:29 ` Anand Jain
2021-07-27 21:17 ` [PATCH 3/7] btrfs: Allocate btrfs_ioctl_get_subvol_info_args " Goldwyn Rodrigues
2021-07-28 5:59 ` Anand Jain [this message]
2021-07-29 17:08 ` David Sterba
2021-07-29 17:22 ` David Sterba
2021-07-27 21:17 ` [PATCH 4/7] btrfs: Allocate btrfs_ioctl_balance_args " Goldwyn Rodrigues
2021-07-28 0:02 ` Darrick J. Wong
2021-07-28 2:04 ` Goldwyn Rodrigues
2021-07-28 1:19 ` kernel test robot
2021-07-27 21:17 ` [PATCH 5/7] btrfs: Allocate btrfs_ioctl_quota_rescan_args " Goldwyn Rodrigues
2021-07-28 6:01 ` Anand Jain
2021-07-27 21:17 ` [PATCH 6/7] btrfs: Allocate btrfs_ioctl_defrag_range_args " Goldwyn Rodrigues
2021-07-28 6:27 ` Anand Jain
2021-07-27 21:17 ` [PATCH 7/7] btrfs: Alloc backref_ctx " Goldwyn Rodrigues
2021-07-28 6:30 ` Anand Jain
-- strict thread matches above, loose matches on Subject: below --
2021-07-27 21:17 [PATCH 0/7] Allocate structures on stack instead of kmalloc() Goldwyn Rodrigues
2021-07-29 16:51 ` David Sterba
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