Re: [RFT PATCH] tee: shm: Remove refcounting of kernel pages

Hi Sumit,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on linus/master v6.19 next-20260213]
[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/Sumit-Garg/tee-shm-Remove-refcounting-of-kernel-pages/20260213-193435
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20260213113317.1728769-1-sumit.garg%40kernel.org
patch subject: [RFT PATCH] tee: shm: Remove refcounting of kernel pages
config: loongarch-randconfig-r071-20260214 (https://download.01.org/0day-ci/archive/20260216/[email protected]/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
rustc: rustc 1.88.0 (6b00bc388 2025-06-23)
smatch version: v0.5.0-8994-gd50c5a4c
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260216/[email protected]/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 <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

All errors (new ones prefixed by >>):

>> drivers/tee/tee_shm.c:475:6: error: call to undeclared function 'iter_is_uvec'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     475 |         if (iter_is_uvec(iter))
         |             ^
   drivers/tee/tee_shm.c:475:6: note: did you mean 'iter_is_iovec'?
   include/linux/uio.h:128:20: note: 'iter_is_iovec' declared here
     128 | static inline bool iter_is_iovec(const struct iov_iter *i)
         |                    ^
   1 error generated.


vim +/iter_is_uvec +475 drivers/tee/tee_shm.c

   399	
   400	static struct tee_shm *
   401	register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags,
   402			    int id)
   403	{
   404		struct tee_device *teedev = ctx->teedev;
   405		struct tee_shm *shm;
   406		unsigned long start, addr;
   407		size_t num_pages, off;
   408		ssize_t len;
   409		void *ret;
   410		int rc;
   411	
   412		if (!tee_device_get(teedev))
   413			return ERR_PTR(-EINVAL);
   414	
   415		if (!teedev->desc->ops->shm_register ||
   416		    !teedev->desc->ops->shm_unregister) {
   417			ret = ERR_PTR(-ENOTSUPP);
   418			goto err_dev_put;
   419		}
   420	
   421		teedev_ctx_get(ctx);
   422	
   423		shm = kzalloc(sizeof(*shm), GFP_KERNEL);
   424		if (!shm) {
   425			ret = ERR_PTR(-ENOMEM);
   426			goto err_ctx_put;
   427		}
   428	
   429		refcount_set(&shm->refcount, 1);
   430		shm->flags = flags;
   431		shm->ctx = ctx;
   432		shm->id = id;
   433		addr = untagged_addr((unsigned long)iter_iov_addr(iter));
   434		start = rounddown(addr, PAGE_SIZE);
   435		num_pages = iov_iter_npages(iter, INT_MAX);
   436		if (!num_pages) {
   437			ret = ERR_PTR(-ENOMEM);
   438			goto err_ctx_put;
   439		}
   440	
   441		shm->pages = kcalloc(num_pages, sizeof(*shm->pages), GFP_KERNEL);
   442		if (!shm->pages) {
   443			ret = ERR_PTR(-ENOMEM);
   444			goto err_free_shm;
   445		}
   446	
   447		len = iov_iter_extract_pages(iter, &shm->pages, LONG_MAX, num_pages, 0,
   448					     &off);
   449		if (unlikely(len <= 0)) {
   450			ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM);
   451			goto err_free_shm_pages;
   452		} else if (DIV_ROUND_UP(len + off, PAGE_SIZE) != num_pages) {
   453			/*
   454			 * If we only got a few pages, update to release the
   455			 * correct amount below.
   456			 */
   457			shm->num_pages = len / PAGE_SIZE;
   458			ret = ERR_PTR(-ENOMEM);
   459			goto err_put_shm_pages;
   460		}
   461	
   462		shm->offset = off;
   463		shm->size = len;
   464		shm->num_pages = num_pages;
   465	
   466		rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages,
   467						     shm->num_pages, start);
   468		if (rc) {
   469			ret = ERR_PTR(rc);
   470			goto err_put_shm_pages;
   471		}
   472	
   473		return shm;
   474	err_put_shm_pages:
 > 475		if (iter_is_uvec(iter))
   476			unpin_user_pages(shm->pages, shm->num_pages);
   477	err_free_shm_pages:
   478		kfree(shm->pages);
   479	err_free_shm:
   480		kfree(shm);
   481	err_ctx_put:
   482		teedev_ctx_put(ctx);
   483	err_dev_put:
   484		tee_device_put(teedev);
   485		return ret;
   486	}
   487	

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