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[67.48.91.116]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-735af9bc906sm622694a34.48.2025.05.30.08.35.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 30 May 2025 08:35:56 -0700 (PDT) Message-ID: <04ba20e6-ce2c-4e47-8884-c563b931cd66@gmail.com> Date: Fri, 30 May 2025 10:35:54 -0500 Precedence: bulk X-Mailing-List: platform-driver-x86@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/4] platform/x86: dell_rbu: Fix list usage To: =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= Cc: LKML , Hans de Goede , platform-driver-x86@vger.kernel.org References: <20250529202758.8440-1-stuart.w.hayes@gmail.com> <20250529202758.8440-3-stuart.w.hayes@gmail.com> <54523dfb-e1ff-fa55-0628-0a8377457f0d@linux.intel.com> Content-Language: en-US From: stuart hayes In-Reply-To: <54523dfb-e1ff-fa55-0628-0a8377457f0d@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 5/30/2025 10:25 AM, Ilpo Järvinen wrote: > On Fri, 30 May 2025, stuart hayes wrote: > >> On 5/30/2025 2:54 AM, Ilpo Järvinen wrote: >>> On Thu, 29 May 2025, Stuart Hayes wrote: >>> >>>> Stop using an entire struct packet_data just for the embedded list_head, >>>> and fix usage of that list_head. >>>> >>>> Fixes: d19f359fbdc6 ("platform/x86: dell_rbu: don't open code >>>> list_for_each_entry*()") >>>> Signed-off-by: Stuart Hayes >>> >>> Isn't this just refactor so Fixes tag for this commit is not warranted? >>> >> >> No. The patch that this fixes had converted the driver to use >> list_for_each_entry*() to loop through the packet list instead of a while >> loop. But it passed (&packet_data_head.list)->next to list_for_each_entry*() >> instead of the list head itself. >> >> That resulted in to issues. In the function that prints the packets, it would >> start with the wrong packet, and in the function that deletes the packets, it >> would get a null pointer dereference when it tried to zero out the data >> associated with the packet that held the actual list head. > > Oh, I see that difference now. Good catch. > > However, that also means the ->next part is wrong and there are two > independent changes here, one that fixes this ->next problem and then the > refactoring of packet_data_head to packet_data_list? > Correct. Do you want those as two separate patches? >>>> --- >>>> drivers/platform/x86/dell/dell_rbu.c | 10 +++++----- >>>> 1 file changed, 5 insertions(+), 5 deletions(-) >>>> >>>> diff --git a/drivers/platform/x86/dell/dell_rbu.c >>>> b/drivers/platform/x86/dell/dell_rbu.c >>>> index 7b019fb72e86..c03d4d55fcc1 100644 >>>> --- a/drivers/platform/x86/dell/dell_rbu.c >>>> +++ b/drivers/platform/x86/dell/dell_rbu.c >>>> @@ -77,14 +77,14 @@ struct packet_data { >>>> int ordernum; >>>> }; >>>> -static struct packet_data packet_data_head; >>>> +static struct list_head packet_data_list; >>>> static struct platform_device *rbu_device; >>>> static int context; >>>> static void init_packet_head(void) >>>> { >>>> - INIT_LIST_HEAD(&packet_data_head.list); >>>> + INIT_LIST_HEAD(&packet_data_list); >>>> rbu_data.packet_read_count = 0; >>>> rbu_data.num_packets = 0; >>>> rbu_data.packetsize = 0; >>>> @@ -183,7 +183,7 @@ static int create_packet(void *data, size_t length) >>>> __must_hold(&rbu_data.lock) >>>> /* initialize the newly created packet headers */ >>>> INIT_LIST_HEAD(&newpacket->list); >>>> - list_add_tail(&newpacket->list, &packet_data_head.list); >>>> + list_add_tail(&newpacket->list, &packet_data_list); >>>> memcpy(newpacket->data, data, length); >>>> @@ -292,7 +292,7 @@ static int packet_read_list(char *data, size_t * >>>> pread_length) >>>> remaining_bytes = *pread_length; >>>> bytes_read = rbu_data.packet_read_count; >>>> - list_for_each_entry(newpacket, (&packet_data_head.list)->next, list) { >>>> + list_for_each_entry(newpacket, &packet_data_list, list) { >>>> bytes_copied = do_packet_read(pdest, newpacket, >>>> remaining_bytes, bytes_read, &temp_count); >>>> remaining_bytes -= bytes_copied; >>>> @@ -315,7 +315,7 @@ static void packet_empty_list(void) >>>> { >>>> struct packet_data *newpacket, *tmp; >>>> - list_for_each_entry_safe(newpacket, tmp, >>>> (&packet_data_head.list)->next, list) { >>>> + list_for_each_entry_safe(newpacket, tmp, &packet_data_list, list) { >>>> list_del(&newpacket->list); >>>> /* >>>> >>> >> >