Re: [PATCH v7 1/2] mctp pcc: Check before sending MCTP PCC response ACK

Hi,

kernel test robot noticed the following build warnings:

[auto build test WARNING on rafael-pm/linux-next]
[also build test WARNING on rafael-pm/bleeding-edge linus/master v6.12-rc7 next-20241115]
[cannot apply to horms-ipvs/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/admiyo-os-amperecomputing-com/mctp-pcc-Check-before-sending-MCTP-PCC-response-ACK/20241114-105151
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
patch link:    https://lore.kernel.org/r/20241114024928.60004-2-admiyo%40os.amperecomputing.com
patch subject: [PATCH v7 1/2] mctp pcc: Check before sending MCTP PCC response ACK
config: x86_64-randconfig-123-20241117 (https://download.01.org/0day-ci/archive/20241117/202411172322.HO4ycC00-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241117/202411172322.HO4ycC00-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot [off-list ref]
| Closes: https://lore.kernel.org/oe-kbuild-all/202411172322.HO4ycC00-lkp@intel.com/ (local)

sparse warnings: (new ones prefixed by >>)

quoted

drivers/mailbox/pcc.c:283:34: sparse: sparse: Using plain integer as NULL pointer
drivers/mailbox/pcc.c:296:27: sparse: sparse: incorrect type in argument 1 (different base types) @@     expected restricted __le32 const [usertype] *p @@     got unsigned int * @@

   drivers/mailbox/pcc.c:296:27: sparse:     expected restricted __le32 const [usertype] *p
   drivers/mailbox/pcc.c:296:27: sparse:     got unsigned int *
   drivers/mailbox/pcc.c: note: in included file (through include/linux/mmzone.h, include/linux/gfp.h, include/linux/slab.h, ...):
   include/linux/page-flags.h:237:46: sparse: sparse: self-comparison always evaluates to false
   include/linux/page-flags.h:237:46: sparse: sparse: self-comparison always evaluates to false

vim +283 drivers/mailbox/pcc.c

   272	
   273	static void check_and_ack(struct pcc_chan_info *pchan, struct mbox_chan *chan)
   274	{
   275		struct acpi_pcct_ext_pcc_shared_memory pcc_hdr;
   276	
   277		if (pchan->type != ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
   278			return;
   279		/* If the memory region has not been mapped, we cannot
   280		 * determine if we need to send the message, but we still
   281		 * need to set the cmd_update flag before returning.
   282		 */
 > 283		if (pchan->chan.shmem == 0) {
   284			pcc_chan_reg_read_modify_write(&pchan->cmd_update);
   285			return;
   286		}
   287		memcpy_fromio(&pcc_hdr, pchan->chan.shmem,
   288			      sizeof(struct acpi_pcct_ext_pcc_shared_memory));
   289		/*
   290		 * The PCC slave subspace channel needs to set the command complete bit
   291		 * after processing message. If the PCC_ACK_FLAG is set, it should also
   292		 * ring the doorbell.
   293		 *
   294		 * The PCC master subspace channel clears chan_in_use to free channel.
   295		 */
 > 296		if (le32_to_cpup(&pcc_hdr.flags) & PCC_ACK_FLAG_MASK)
   297			pcc_send_data(chan, NULL);
   298		else
   299			pcc_chan_reg_read_modify_write(&pchan->cmd_update);
   300	}
   301	

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