From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D455B2040A9 for ; Tue, 4 Mar 2025 13:06:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741093585; cv=none; b=NCJvPBUkgyw7C2sGntE7qroDB/IpOGCKV0zumzKDoy+ILf1ptFJqdJ0nhKaThYSlyTrwFGe3owH/G324v0vk4YTzokhFxh4YY73PNtUZyTTddaEaOilabKSPZZMB+20KwhELdyX6UXXhdZjAgqzYvbxlusnqPVPfKWAyAiFbFiI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741093585; c=relaxed/simple; bh=18uFT/YDKZurxGeH4PAL/MS8l5fsl/TsASOsfxnTUjk=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=VRFv8SJCvOyQh7vtq7NXGAha76WSWx2boXV6OsSaBGa9V9/oJLRe1vjikW4Kf4p6ZEkcNWTjYinKK9uLCB9URljY6wCiJHUOtC4K7kcdbVQMfMglm2Rsg5Bs5kHHVYUw+pjLqb2iqsTtuKVZpW7VSSsNcbFD22jB8jcKfzQ5QNs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kjSZtOWe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kjSZtOWe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 351EEC4CEE5; Tue, 4 Mar 2025 13:06:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741093585; bh=18uFT/YDKZurxGeH4PAL/MS8l5fsl/TsASOsfxnTUjk=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=kjSZtOWe2Qb5nfsbsvzIgmS5IRVPhjpaJ5sHncyXthqVwwuq5nPku1QfWETsur3wG pVXBmCokDDEDzegUvEvObEQiPs15vbgo+kqnQWwROKmM8vng0ibqmFcJ7sjBHrM7Pv wNj7kFlzALlWtonmRfws1RTQYyFEThHtLAEzdVwlIJIyn9esCPa1yXW7loOBAT0Gmv Uma4JWUqnVg2dpMr1VCWsjXuHvt6GNVQ0Ap9YnIlhq9sc++R9XZ5kiauyOkM0q2aUo TU5bcZFEP+UQfWzeIzRbmZihnXQOBi1iuNt90nI+aLKN9ugrnZ/rTObxSH8BZ8/eek 1D7aYTD4mZ3sw== Message-ID: Subject: Re: [PATCH v2 04/15] pidfs: add inode allocation From: Jeff Layton To: Christian Brauner , Oleg Nesterov Cc: linux-fsdevel@vger.kernel.org, Lennart Poettering , Daan De Meyer , Mike Yuan Date: Tue, 04 Mar 2025 08:06:24 -0500 In-Reply-To: <20250304-work-pidfs-kill_on_last_close-v2-4-44fdacfaa7b7@kernel.org> References: <20250304-work-pidfs-kill_on_last_close-v2-0-44fdacfaa7b7@kernel.org> <20250304-work-pidfs-kill_on_last_close-v2-4-44fdacfaa7b7@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV 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Tue, 2025-03-04 at 10:41 +0100, Christian Brauner wrote: > Signed-off-by: Christian Brauner > --- > fs/pidfs.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 52 insertions(+) >=20 > diff --git a/fs/pidfs.c b/fs/pidfs.c > index ecc0dd886714..eaecb0a947f0 100644 > --- a/fs/pidfs.c > +++ b/fs/pidfs.c > @@ -24,6 +24,27 @@ > #include "internal.h" > #include "mount.h" > =20 > +static struct kmem_cache *pidfs_cachep __ro_after_init; > + > +/* > + * Stashes information that userspace needs to access even after the > + * process has been reaped. > + */ > +struct pidfs_exit_info { > + __u64 cgroupid; > + __u64 exit_code; This is changed to __s32 in the next patch. Might as well do that here. > +}; > + > +struct pidfs_inode { > + struct pidfs_exit_info exit_info; > + struct inode vfs_inode; > +}; > + > +static inline struct pidfs_inode *pidfs_i(struct inode *inode) > +{ > + return container_of(inode, struct pidfs_inode, vfs_inode); > +} > + > static struct rb_root pidfs_ino_tree =3D RB_ROOT; > =20 > #if BITS_PER_LONG =3D=3D 32 > @@ -492,9 +513,29 @@ static void pidfs_evict_inode(struct inode *inode) > put_pid(pid); > } > =20 > +static struct inode *pidfs_alloc_inode(struct super_block *sb) > +{ > + struct pidfs_inode *pi; > + > + pi =3D alloc_inode_sb(sb, pidfs_cachep, GFP_KERNEL); > + if (!pi) > + return NULL; > + > + memset(&pi->exit_info, 0, sizeof(pi->exit_info)); > + > + return &pi->vfs_inode; > +} > + > +static void pidfs_free_inode(struct inode *inode) > +{ > + kmem_cache_free(pidfs_cachep, pidfs_i(inode)); > +} > + > static const struct super_operations pidfs_sops =3D { > + .alloc_inode =3D pidfs_alloc_inode, > .drop_inode =3D generic_delete_inode, > .evict_inode =3D pidfs_evict_inode, > + .free_inode =3D pidfs_free_inode, > .statfs =3D simple_statfs, > }; > =20 > @@ -704,8 +745,19 @@ struct file *pidfs_alloc_file(struct pid *pid, unsig= ned int flags) > return pidfd_file; > } > =20 > +static void pidfs_inode_init_once(void *data) > +{ > + struct pidfs_inode *pi =3D data; > + > + inode_init_once(&pi->vfs_inode); > +} > + > void __init pidfs_init(void) > { > + pidfs_cachep =3D kmem_cache_create("pidfs_cache", sizeof(struct pidfs_i= node), 0, > + (SLAB_HWCACHE_ALIGN | SLAB_RECLAIM_ACCOUNT | > + SLAB_ACCOUNT | SLAB_PANIC), > + pidfs_inode_init_once); > pidfs_mnt =3D kern_mount(&pidfs_type); > if (IS_ERR(pidfs_mnt)) > panic("Failed to mount pidfs pseudo filesystem"); >=20 Reviewed-by: Jeff Layton