diff mbox series

[2/2] mm: introduce vma_set_file function

Message ID 20200914132920.59183-3-christian.koenig@amd.com
State New, archived
Headers show
Series [1/2] drm/shmem-helpers: revert "Redirect mmap for imported dma-buf" | expand

Commit Message

Christian König Sept. 14, 2020, 1:29 p.m. UTC
Add the new vma_set_file() function to allow changing
vma->vm_file with the necessary refcount dance.

Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/dma-buf/dma-buf.c | 16 +++++-----------
 include/linux/mm.h        |  2 ++
 mm/mmap.c                 | 16 ++++++++++++++++
 3 files changed, 23 insertions(+), 11 deletions(-)

Comments

kernel test robot Sept. 15, 2020, 9:19 a.m. UTC | #1
Hi "Christian,

I love your patch! Yet something to improve:

[auto build test ERROR on hnaz-linux-mm/master]
[also build test ERROR on drm-intel/for-linux-next drm-tip/drm-tip linus/master v5.9-rc5 next-20200914]
[cannot apply to tegra-drm/drm/tegra/for-next drm-exynos/exynos-drm-next drm/drm-next]
[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]

url:    https://github.com/0day-ci/linux/commits/Christian-K-nig/drm-shmem-helpers-revert-Redirect-mmap-for-imported-dma-buf/20200914-222921
base:   https://github.com/hnaz/linux-mm master
config: h8300-randconfig-r023-20200914 (attached as .config)
compiler: h8300-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=h8300 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   h8300-linux-ld: drivers/dma-buf/dma-buf.o: in function `dma_buf_mmap':
>> drivers/dma-buf/dma-buf.c:1166: undefined reference to `vma_set_file'
>> h8300-linux-ld: drivers/dma-buf/dma-buf.c:1172: undefined reference to `vma_set_file'
   h8300-linux-ld: drivers/leds/leds-lp55xx-common.o: in function `devm_led_classdev_register':
   include/linux/leds.h:200: undefined reference to `devm_led_classdev_register_ext'

# https://github.com/0day-ci/linux/commit/c558278651bbea7cb67487890a983608764cc7f4
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Christian-K-nig/drm-shmem-helpers-revert-Redirect-mmap-for-imported-dma-buf/20200914-222921
git checkout c558278651bbea7cb67487890a983608764cc7f4
vim +1166 drivers/dma-buf/dma-buf.c

  1127	
  1128	
  1129	/**
  1130	 * dma_buf_mmap - Setup up a userspace mmap with the given vma
  1131	 * @dmabuf:	[in]	buffer that should back the vma
  1132	 * @vma:	[in]	vma for the mmap
  1133	 * @pgoff:	[in]	offset in pages where this mmap should start within the
  1134	 *			dma-buf buffer.
  1135	 *
  1136	 * This function adjusts the passed in vma so that it points at the file of the
  1137	 * dma_buf operation. It also adjusts the starting pgoff and does bounds
  1138	 * checking on the size of the vma. Then it calls the exporters mmap function to
  1139	 * set up the mapping.
  1140	 *
  1141	 * Can return negative error values, returns 0 on success.
  1142	 */
  1143	int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
  1144			 unsigned long pgoff)
  1145	{
  1146		struct file *oldfile;
  1147		int ret;
  1148	
  1149		if (WARN_ON(!dmabuf || !vma))
  1150			return -EINVAL;
  1151	
  1152		/* check if buffer supports mmap */
  1153		if (!dmabuf->ops->mmap)
  1154			return -EINVAL;
  1155	
  1156		/* check for offset overflow */
  1157		if (pgoff + vma_pages(vma) < pgoff)
  1158			return -EOVERFLOW;
  1159	
  1160		/* check for overflowing the buffer's size */
  1161		if (pgoff + vma_pages(vma) >
  1162		    dmabuf->size >> PAGE_SHIFT)
  1163			return -EINVAL;
  1164	
  1165		/* readjust the vma */
> 1166		oldfile = vma_set_file(vma, dmabuf->file);
  1167		vma->vm_pgoff = pgoff;
  1168	
  1169		ret = dmabuf->ops->mmap(dmabuf, vma);
  1170		/* restore old parameters on failure */
  1171		if (ret)
> 1172			vma_set_file(vma, oldfile);
  1173	
  1174		return ret;
  1175	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
kernel test robot Sept. 15, 2020, 11:57 a.m. UTC | #2
Hi "Christian,

I love your patch! Yet something to improve:

[auto build test ERROR on hnaz-linux-mm/master]
[also build test ERROR on drm-intel/for-linux-next drm-tip/drm-tip linus/master v5.9-rc5 next-20200915]
[cannot apply to tegra-drm/drm/tegra/for-next drm-exynos/exynos-drm-next drm/drm-next]
[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]

url:    https://github.com/0day-ci/linux/commits/Christian-K-nig/drm-shmem-helpers-revert-Redirect-mmap-for-imported-dma-buf/20200914-222921
base:   https://github.com/hnaz/linux-mm master
config: sh-allmodconfig (attached as .config)
compiler: sh4-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=sh 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   sh4-linux-ld: drivers/dma-buf/dma-buf.o: in function `dma_buf_mmap':
>> (.text+0x8dc): undefined reference to `vma_set_file'

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 1699a8e309ef..672f3525ba74 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -1163,20 +1163,14 @@  int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
 		return -EINVAL;
 
 	/* readjust the vma */
-	get_file(dmabuf->file);
-	oldfile = vma->vm_file;
-	vma->vm_file = dmabuf->file;
+	oldfile = vma_set_file(vma, dmabuf->file);
 	vma->vm_pgoff = pgoff;
 
 	ret = dmabuf->ops->mmap(dmabuf, vma);
-	if (ret) {
-		/* restore old parameters on failure */
-		vma->vm_file = oldfile;
-		fput(dmabuf->file);
-	} else {
-		if (oldfile)
-			fput(oldfile);
-	}
+	/* restore old parameters on failure */
+	if (ret)
+		vma_set_file(vma, oldfile);
+
 	return ret;
 
 }
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1983e08f5906..398a6fdaad1e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2688,6 +2688,8 @@  static inline void vma_set_page_prot(struct vm_area_struct *vma)
 }
 #endif
 
+struct file *vma_set_file(struct vm_area_struct *vma, struct file *file);
+
 #ifdef CONFIG_NUMA_BALANCING
 unsigned long change_prot_numa(struct vm_area_struct *vma,
 			unsigned long start, unsigned long end);
diff --git a/mm/mmap.c b/mm/mmap.c
index 40248d84ad5f..d3c3c510f643 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -136,6 +136,22 @@  void vma_set_page_prot(struct vm_area_struct *vma)
 	WRITE_ONCE(vma->vm_page_prot, vm_page_prot);
 }
 
+/*
+ * Change backing file, only valid to use during initial VMA setup.
+ */
+struct file *vma_set_file(struct vm_area_struct *vma, struct file *file)
+{
+	if (file)
+	        get_file(file);
+
+	swap(vma->vm_file, file);
+
+	if (file)
+		fput(file);
+
+	return file;
+}
+
 /*
  * Requires inode->i_mapping->i_mmap_rwsem
  */