RE: [5.3] ucc_geth: Fix to avoid IS_ERR_VALUE abuses and dead code on 64bit systems.

From: netdev-owner@vger.kernel.org [mailto:netdev-owner@vger.kernel.org] On Behalf Of Arvind Yadav

IS_ERR_VALUE() assumes that parameter is an unsigned long.
It can not be used to check if 'unsigned int' is passed insted.
Which tends to reflect an error.
In 64bit architectures sizeof (int) == 4 && sizeof (long) == 8.
IS_ERR_VALUE(x) is ((x) >= (unsigned long)-4095).
IS_ERR_VALUE() of 'unsigned int' is always false because the 32bit
value is zero extended to 64 bits.

You are being far too wordy above, and definitely below.

Now problem in Freescale QEGigabit Ethernet-:
                                 drivers/net/ethernet/freescale/ucc_geth.c

...

         qe_muram_addr(init_enet_pram_offset);

qe_muram_alloc (a.k.a. cpm_muram_alloc) returns unsigned long.
Return value store in a u32 (init_enet_offset, exf_glbl_param_offset,
rx_glbl_pram_offset, tx_glbl_pram_offset, send_q_mem_reg_offset,
thread_dat_tx_offset, thread_dat_rx_offset, scheduler_offset,
tx_fw_statistics_pram_offset, rx_fw_statistics_pram_offset,
rx_irq_coalescing_tbl_offset, rx_bd_qs_tbl_offset, tx_bd_ring_offset,
init_enet_pram_offset and rx_bd_ring_offset).

Inpenetrable...

If qe_muram_alloc will return any error, Then IS_ERR_VALUE will always
return 0. it'll not call ucc_fast_free for any failure. Inside 'if code'
will be a dead code on 64bit. Even qe_muram_addr will return wrong
virtual address. Which can cause an error.

 kfree((void *)ugeth->tx_bd_ring_offset[i]);

Erm, kfree() isn't the right function for things allocated by qe_muram_alloc().

I still thing you need to stop this code using IS_ERR_VALUE() at all.

	David