Subject: Re: [PATCH] Remove lots of IS_ERR_VALUE abuses.

From: arvind Yadav <[email-masked]>
Date: Thu, 7 Jul 2016 20:47:09 +0530

As per your concern, I have change commit message. Submit other patch.

Thanks,
Arvind Yadav

On Thursday 07 July 2016 01:40 PM, Arnd Bergmann wrote:
> On Thursday, July 7, 2016 12:47:43 AM CEST Arvind Yadav wrote:
>>      Most users of IS_ERR_VALUE() in the kernel are wrong, as they
>>      pass an 'int' into a function that takes an 'unsigned long'
>>      argument. This happens to work because the type is sign-extended
>>      on 64-bit architectures before it gets converted into an
>>      unsigned type.
>>
>>      However, anything that passes an 'unsigned short' or 'unsigned int'
>>      argument into IS_ERR_VALUE() is guaranteed to be broken, as are
>>      8-bit integers and types that are wider than 'unsigned long'.
>>
>>      Andrzej Hajda has already fixed a lot of the worst abusers that
>>      were causing actual bugs, but it would be nice to prevent any
>>      users that are not passing 'unsigned long' arguments.
>>
>>      This patch changes all users of IS_ERR_VALUE() that I could find
>>      on 32-bit ARM randconfig builds and x86 allmodconfig. For the
>>      moment, this doesn't change the definition of IS_ERR_VALUE()
>>      because there are probably still architecture specific users
>>      elsewhere.
>>
>>      Almost all the warnings I got are for files that are better off
>>      using 'if (err)' or 'if (err < 0)'.
>>      The only legitimate user I could find that we get a warning for
>>      is the (32-bit only) freescale gigabit ethernet driver.
>>
>>      I was using this definition for testing:
>>
>>       #define IS_ERR_VALUE(x) ((unsigned long*)NULL == (typeof (x)*)NULL && \
>>        unlikely((unsigned long long)(x) >= (unsigned long long)(typeof(x))-MAX_ERRNO))
>>
>>      which ends up making all 16-bit or wider types work correctly with
>>      the most plausible interpretation of what IS_ERR_VALUE() was supposed
>>      to return according to its users, but also causes a compile-time
>>      warning for any users that do not pass an 'unsigned long' argument.
>>
>> Signed-off-by: Arvind Yadav <[email-masked]>
> The above is my changelog text for commit 287980e49f, but it's not my patch.
>
> Your changes look fine, but reusing my description there seems wrong.
> Can you add a new description and just point to my commit instead?
>
> 	Arnd
>
>>   drivers/net/ethernet/freescale/ucc_geth.c | 30 +++++++++++++++---------------
>>   1 file changed, 15 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/freescale/ucc_geth.c b/drivers/net/ethernet/freescale/ucc_geth.c
>> index 5bf1ade..c1ead2c 100644
>> --- a/drivers/net/ethernet/freescale/ucc_geth.c
>> +++ b/drivers/net/ethernet/freescale/ucc_geth.c
>> @@ -289,7 +289,7 @@ static int fill_init_enet_entries(struct ucc_geth_private *ugeth,
>>   		else {
>>   			init_enet_offset =
>>   			    qe_muram_alloc(thread_size, thread_alignment);
>> -			if (IS_ERR_VALUE(init_enet_offset)) {
>> +			if (init_enet_offset < 0) {
>>   				if (netif_msg_ifup(ugeth))
>>   					pr_err("Can not allocate DPRAM memory\n");
>>   				qe_put_snum((u8) snum);
>> @@ -2234,7 +2234,7 @@ static int ucc_geth_alloc_tx(struct ucc_geth_private *ugeth)
>>   			ugeth->tx_bd_ring_offset[j] =
>>   			    qe_muram_alloc(length,
>>   					   UCC_GETH_TX_BD_RING_ALIGNMENT);
>> -			if (!IS_ERR_VALUE(ugeth->tx_bd_ring_offset[j]))
>> +			if (!ugeth->tx_bd_ring_offset[j])
>>   				ugeth->p_tx_bd_ring[j] =
>>   				    (u8 __iomem *) qe_muram_addr(ugeth->
>>   							 tx_bd_ring_offset[j]);
>> @@ -2311,7 +2311,7 @@ static int ucc_geth_alloc_rx(struct ucc_geth_private *ugeth)
>>   			ugeth->rx_bd_ring_offset[j] =
>>   			    qe_muram_alloc(length,
>>   					   UCC_GETH_RX_BD_RING_ALIGNMENT);
>> -			if (!IS_ERR_VALUE(ugeth->rx_bd_ring_offset[j]))
>> +			if (!ugeth->rx_bd_ring_offset[j])
>>   				ugeth->p_rx_bd_ring[j] =
>>   				    (u8 __iomem *) qe_muram_addr(ugeth->
>>   							 rx_bd_ring_offset[j]);
>> @@ -2521,7 +2521,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   	ugeth->tx_glbl_pram_offset =
>>   	    qe_muram_alloc(sizeof(struct ucc_geth_tx_global_pram),
>>   			   UCC_GETH_TX_GLOBAL_PRAM_ALIGNMENT);
>> -	if (IS_ERR_VALUE(ugeth->tx_glbl_pram_offset)) {
>> +	if (ugeth->tx_glbl_pram_offset < 0) {
>>   		if (netif_msg_ifup(ugeth))
>>   			pr_err("Can not allocate DPRAM memory for p_tx_glbl_pram\n");
>>   		return -ENOMEM;
>> @@ -2541,7 +2541,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   			   sizeof(struct ucc_geth_thread_data_tx) +
>>   			   32 * (numThreadsTxNumerical == 1),
>>   			   UCC_GETH_THREAD_DATA_ALIGNMENT);
>> -	if (IS_ERR_VALUE(ugeth->thread_dat_tx_offset)) {
>> +	if (ugeth->thread_dat_tx_offset < 0) {
>>   		if (netif_msg_ifup(ugeth))
>>   			pr_err("Can not allocate DPRAM memory for p_thread_data_tx\n");
>>   		return -ENOMEM;
>> @@ -2568,7 +2568,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   	    qe_muram_alloc(ug_info->numQueuesTx *
>>   			   sizeof(struct ucc_geth_send_queue_qd),
>>   			   UCC_GETH_SEND_QUEUE_QUEUE_DESCRIPTOR_ALIGNMENT);
>> -	if (IS_ERR_VALUE(ugeth->send_q_mem_reg_offset)) {
>> +	if (ugeth->send_q_mem_reg_offset < 0) {
>>   		if (netif_msg_ifup(ugeth))
>>   			pr_err("Can not allocate DPRAM memory for p_send_q_mem_reg\n");
>>   		return -ENOMEM;
>> @@ -2609,7 +2609,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   		ugeth->scheduler_offset =
>>   		    qe_muram_alloc(sizeof(struct ucc_geth_scheduler),
>>   				   UCC_GETH_SCHEDULER_ALIGNMENT);
>> -		if (IS_ERR_VALUE(ugeth->scheduler_offset)) {
>> +		if (ugeth->scheduler_offset < 0) {
>>   			if (netif_msg_ifup(ugeth))
>>   				pr_err("Can not allocate DPRAM memory for p_scheduler\n");
>>   			return -ENOMEM;
>> @@ -2656,7 +2656,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   		    qe_muram_alloc(sizeof
>>   				   (struct ucc_geth_tx_firmware_statistics_pram),
>>   				   UCC_GETH_TX_STATISTICS_ALIGNMENT);
>> -		if (IS_ERR_VALUE(ugeth->tx_fw_statistics_pram_offset)) {
>> +		if (ugeth->tx_fw_statistics_pram_offset < 0) {
>>   			if (netif_msg_ifup(ugeth))
>>   				pr_err("Can not allocate DPRAM memory for p_tx_fw_statistics_pram\n");
>>   			return -ENOMEM;
>> @@ -2693,7 +2693,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   	ugeth->rx_glbl_pram_offset =
>>   	    qe_muram_alloc(sizeof(struct ucc_geth_rx_global_pram),
>>   			   UCC_GETH_RX_GLOBAL_PRAM_ALIGNMENT);
>> -	if (IS_ERR_VALUE(ugeth->rx_glbl_pram_offset)) {
>> +	if (ugeth->rx_glbl_pram_offset < 0) {
>>   		if (netif_msg_ifup(ugeth))
>>   			pr_err("Can not allocate DPRAM memory for p_rx_glbl_pram\n");
>>   		return -ENOMEM;
>> @@ -2712,7 +2712,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   	    qe_muram_alloc(numThreadsRxNumerical *
>>   			   sizeof(struct ucc_geth_thread_data_rx),
>>   			   UCC_GETH_THREAD_DATA_ALIGNMENT);
>> -	if (IS_ERR_VALUE(ugeth->thread_dat_rx_offset)) {
>> +	if (ugeth->thread_dat_rx_offset < 0) {
>>   		if (netif_msg_ifup(ugeth))
>>   			pr_err("Can not allocate DPRAM memory for p_thread_data_rx\n");
>>   		return -ENOMEM;
>> @@ -2733,7 +2733,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   		    qe_muram_alloc(sizeof
>>   				   (struct ucc_geth_rx_firmware_statistics_pram),
>>   				   UCC_GETH_RX_STATISTICS_ALIGNMENT);
>> -		if (IS_ERR_VALUE(ugeth->rx_fw_statistics_pram_offset)) {
>> +		if (ugeth->rx_fw_statistics_pram_offset < 0) {
>>   			if (netif_msg_ifup(ugeth))
>>   				pr_err("Can not allocate DPRAM memory for p_rx_fw_statistics_pram\n");
>>   			return -ENOMEM;
>> @@ -2753,7 +2753,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   	    qe_muram_alloc(ug_info->numQueuesRx *
>>   			   sizeof(struct ucc_geth_rx_interrupt_coalescing_entry)
>>   			   + 4, UCC_GETH_RX_INTERRUPT_COALESCING_ALIGNMENT);
>> -	if (IS_ERR_VALUE(ugeth->rx_irq_coalescing_tbl_offset)) {
>> +	if (ugeth->rx_irq_coalescing_tbl_offset < 0) {
>>   		if (netif_msg_ifup(ugeth))
>>   			pr_err("Can not allocate DPRAM memory for p_rx_irq_coalescing_tbl\n");
>>   		return -ENOMEM;
>> @@ -2819,7 +2819,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   			   (sizeof(struct ucc_geth_rx_bd_queues_entry) +
>>   			    sizeof(struct ucc_geth_rx_prefetched_bds)),
>>   			   UCC_GETH_RX_BD_QUEUES_ALIGNMENT);
>> -	if (IS_ERR_VALUE(ugeth->rx_bd_qs_tbl_offset)) {
>> +	if (ugeth->rx_bd_qs_tbl_offset < 0) {
>>   		if (netif_msg_ifup(ugeth))
>>   			pr_err("Can not allocate DPRAM memory for p_rx_bd_qs_tbl\n");
>>   		return -ENOMEM;
>> @@ -2905,7 +2905,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   		ugeth->exf_glbl_param_offset =
>>   		    qe_muram_alloc(sizeof(struct ucc_geth_exf_global_pram),
>>   		UCC_GETH_RX_EXTENDED_FILTERING_GLOBAL_PARAMETERS_ALIGNMENT);
>> -		if (IS_ERR_VALUE(ugeth->exf_glbl_param_offset)) {
>> +		if (ugeth->exf_glbl_param_offset < 0) {
>>   			if (netif_msg_ifup(ugeth))
>>   				pr_err("Can not allocate DPRAM memory for p_exf_glbl_param\n");
>>   			return -ENOMEM;
>> @@ -3039,7 +3039,7 @@ static int ucc_geth_startup(struct ucc_geth_private *ugeth)
>>   
>>   	/* Allocate InitEnet command parameter structure */
>>   	init_enet_pram_offset = qe_muram_alloc(sizeof(struct ucc_geth_init_pram), 4);
>> -	if (IS_ERR_VALUE(init_enet_pram_offset)) {
>> +	if (init_enet_pram_offset < 0) {
>>   		if (netif_msg_ifup(ugeth))
>>   			pr_err("Can not allocate DPRAM memory for p_init_enet_pram\n");
>>   		return -ENOMEM;
>>
>

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