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Tue, 30 Sep 2025 02:26:56 -0700 (PDT) Message-ID: <342929a3-ac5f-4953-a763-b81c60e66554@gmail.com> Date: Tue, 30 Sep 2025 10:27:06 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] btrfs: Refactor allocation size calculation in kzalloc() To: Qu Wenruo , clm@fb.com, dsterba@suse.com Cc: linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, david.hunter.linux@gmail.com, linux-kernel-mentees@lists.linuxfoundation.org References: <20250930091440.25078-1-mehdi.benhadjkhelifa@gmail.com> <76fa5e79-c7e8-4637-bf51-c0e6f4e04f51@gmx.com> Content-Language: en-US From: Mehdi Ben Hadj Khelifa In-Reply-To: <76fa5e79-c7e8-4637-bf51-c0e6f4e04f51@gmx.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 9/30/25 10:19 AM, Qu Wenruo wrote: > > > 在 2025/9/30 18:44, Mehdi Ben Hadj Khelifa 写道: >> Wrap allocation size calculation in size_add() and size_mul() to avoid >> any potential overflow. >> >> Signed-off-by: Mehdi Ben Hadj Khelifa >> --- >>   fs/btrfs/volumes.c | 11 +++++------ >>   1 file changed, 5 insertions(+), 6 deletions(-) >> >> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c >> index c6e3efd6f602..3f1f19b28aac 100644 >> --- a/fs/btrfs/volumes.c >> +++ b/fs/btrfs/volumes.c >> @@ -6076,12 +6076,11 @@ struct btrfs_io_context >> *alloc_btrfs_io_context(struct btrfs_fs_info *fs_info, >>   { >>       struct btrfs_io_context *bioc; >> -    bioc = kzalloc( >> -         /* The size of btrfs_io_context */ >> -        sizeof(struct btrfs_io_context) + >> -        /* Plus the variable array for the stripes */ >> -        sizeof(struct btrfs_io_stripe) * (total_stripes), >> -        GFP_NOFS); >> +    /* The size of btrfs_io_context */ >> +    /* Plus the variable array for the stripes */ >> +    bioc = kzalloc(size_add(sizeof(struct btrfs_io_context), > > Please use struct_size() instead. > > And if you're using struct_size() there iwll be no need for any comments. Understood, I will get v2 on the way with your recommendation. Thank you for the suggestion. Regards, Mehdi >> +                size_mul(sizeof(struct btrfs_io_stripe), >> +                        total_stripes)), GFP_NOFS); >>       if (!bioc) >>           return NULL; >