From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-189.mta0.migadu.com (out-189.mta0.migadu.com [91.218.175.189]) (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 CF9AB22AE65 for ; Fri, 9 Jan 2026 18:16:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.189 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767982572; cv=none; b=jTb/FQW/VAV8WLgyQORLhlg3GwSc04g4gxR+PuYp6cjc+gUwdGLQBpucrIj44HdT7Z4tSQN1s58jq4l1K8Xn/i5FFHRHacGShlUJusYBPyEq5IGDH3Z/dfIoAEjw5O9zOkMPMZ/OyEvDgsc8dAtxdRft/jBvG24zes9HSZkLRPY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767982572; c=relaxed/simple; bh=ML7xH8bdEeUUQLjoAoECBAy95ypOvkyEbD46iVVfPVc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ibw9BiWqpgAGWh8h5fbY9I0furB7vLDKvfitwPU72PRt3YxcsaPV/30L/jROYey4CkryFjmiIxIWWGPDzv3EkLNHq3akoUa0IXkvTe3aig30amglHVJPtfAywZ9ATf0kHa25fHFzuCGfLMVvthttkz3N6D7gPeelEFVvuztLPhg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=E41qEvWx; arc=none smtp.client-ip=91.218.175.189 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="E41qEvWx" Message-ID: <71c80294-9602-4302-a823-00a0fe7ed7c7@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1767982567; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GbJmJnSbNyL5FE7DeAV7iny/pYwmAwxYW049CqQZNOg=; b=E41qEvWxNQ9SI+HO9X93b+aYH/WnZMukkTwx7iGpKJEC9i+2AzATFlT39LvdMN1P2Rhosg Ed952cp2rpLADfaSO0Kz4Wy0IOpVdW/g1div2QCGPCPQMCcDMHCnEcRg2hjYmfPoSYia+x x12zvGsiKedK4WWzbHFH9Z6jxSdFTTw= Date: Fri, 9 Jan 2026 10:16:02 -0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v3 04/16] bpf: Convert bpf_selem_unlink to failable To: Amery Hung Cc: netdev@vger.kernel.org, alexei.starovoitov@gmail.com, andrii@kernel.org, daniel@iogearbox.net, memxor@gmail.com, martin.lau@kernel.org, kpsingh@kernel.org, yonghong.song@linux.dev, song@kernel.org, haoluo@google.com, kernel-team@meta.com, bpf@vger.kernel.org References: <20251218175628.1460321-1-ameryhung@gmail.com> <20251218175628.1460321-5-ameryhung@gmail.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau In-Reply-To: <20251218175628.1460321-5-ameryhung@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 12/18/25 9:56 AM, Amery Hung wrote: > To prepare changing both bpf_local_storage_map_bucket::lock and > bpf_local_storage::lock to rqspinlock, convert bpf_selem_unlink() to > failable. It still always succeeds and returns 0 until the change > happens. No functional change. > > For bpf_local_storage_map_free(), WARN_ON() for now as no real error > will happen until we switch to rqspinlock. > > __must_check is added to the function declaration locally to make sure > all callers are accounted for during the conversion. I don't see __must_check. The same for patch 2. > > Signed-off-by: Amery Hung > --- > include/linux/bpf_local_storage.h | 2 +- > kernel/bpf/bpf_cgrp_storage.c | 3 +-- > kernel/bpf/bpf_inode_storage.c | 4 +--- > kernel/bpf/bpf_local_storage.c | 8 +++++--- > kernel/bpf/bpf_task_storage.c | 4 +--- > net/core/bpf_sk_storage.c | 4 +--- > 6 files changed, 10 insertions(+), 15 deletions(-) > > diff --git a/include/linux/bpf_local_storage.h b/include/linux/bpf_local_storage.h > index 6cabf5154cf6..a94e12ddd83d 100644 > --- a/include/linux/bpf_local_storage.h > +++ b/include/linux/bpf_local_storage.h > @@ -176,7 +176,7 @@ int bpf_local_storage_map_check_btf(const struct bpf_map *map, > void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage, > struct bpf_local_storage_elem *selem); > > -void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now); > +int bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now); > > int bpf_selem_link_map(struct bpf_local_storage_map *smap, > struct bpf_local_storage_elem *selem); > diff --git a/kernel/bpf/bpf_cgrp_storage.c b/kernel/bpf/bpf_cgrp_storage.c > index 0687a760974a..8fef24fcac68 100644 > --- a/kernel/bpf/bpf_cgrp_storage.c > +++ b/kernel/bpf/bpf_cgrp_storage.c > @@ -118,8 +118,7 @@ static int cgroup_storage_delete(struct cgroup *cgroup, struct bpf_map *map) > if (!sdata) > return -ENOENT; > > - bpf_selem_unlink(SELEM(sdata), false); > - return 0; > + return bpf_selem_unlink(SELEM(sdata), false); > } > > static long bpf_cgrp_storage_delete_elem(struct bpf_map *map, void *key) > diff --git a/kernel/bpf/bpf_inode_storage.c b/kernel/bpf/bpf_inode_storage.c > index e54cce2b9175..cedc99184dad 100644 > --- a/kernel/bpf/bpf_inode_storage.c > +++ b/kernel/bpf/bpf_inode_storage.c > @@ -110,9 +110,7 @@ static int inode_storage_delete(struct inode *inode, struct bpf_map *map) > if (!sdata) > return -ENOENT; > > - bpf_selem_unlink(SELEM(sdata), false); > - > - return 0; > + return bpf_selem_unlink(SELEM(sdata), false); > } > > static long bpf_fd_inode_storage_delete_elem(struct bpf_map *map, void *key) > diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c > index 0e3fa5fbaaf3..fa629a180e9e 100644 > --- a/kernel/bpf/bpf_local_storage.c > +++ b/kernel/bpf/bpf_local_storage.c > @@ -367,7 +367,7 @@ static void bpf_selem_link_map_nolock(struct bpf_local_storage_map *smap, > hlist_add_head_rcu(&selem->map_node, &b->list); > } > > -void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) > +int bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) > { > struct bpf_local_storage *local_storage; > bool free_local_storage = false; > @@ -377,7 +377,7 @@ void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) > > if (unlikely(!selem_linked_to_storage_lockless(selem))) > /* selem has already been unlinked from sk */ > - return; > + return 0; > > local_storage = rcu_dereference_check(selem->local_storage, > bpf_rcu_lock_held()); > @@ -402,6 +402,8 @@ void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool reuse_now) > > if (free_local_storage) > bpf_local_storage_free(local_storage, reuse_now); > + > + return err; err is not used in patch 3 and then becomes useful in patch 4. The ai-review discovered issue on err also. Squash patch 4 into patch 3. It will be easier to read. > } > > void __bpf_local_storage_insert_cache(struct bpf_local_storage *local_storage, > @@ -837,7 +839,7 @@ void bpf_local_storage_map_free(struct bpf_map *map, > struct bpf_local_storage_elem, map_node))) { > if (busy_counter) > this_cpu_inc(*busy_counter); > - bpf_selem_unlink(selem, true); > + WARN_ON(bpf_selem_unlink(selem, true)); nit. I would add __must_check to the needed functions in a single patch when everything is ready instead of having an intermediate WARN_ON here and then removed it later.