diff mbox series

[PATCHv2,1/2] mm: eliminate ifdef of HAVE_IOREMAP_PROT in .c files

Message ID SG2PR01MB295111ED8F547B9F99DB9FA99FAD9@SG2PR01MB2951.apcprd01.prod.exchangelabs.com (mailing list archive)
State Changes Requested
Headers show
Series [PATCHv2,1/2] mm: eliminate ifdef of HAVE_IOREMAP_PROT in .c files | expand

Commit Message

Wang Wenhu June 15, 2022, 5:57 a.m. UTC 
It is recommended in the "Conditional Compilation" chapter of kernel
coding-style documentation that preprocessor conditionals should not
be used in .c files wherever possible.

As for the macro CONFIG_HAVE_IOREMAP_PROT, now it's a proper chance
to eliminate it in .c files which are referencers. We constrict its usage
only to mm/memory.c.
HAVE_IOREMAP_PROT is supported by part of archectures such as powerpc and
x86, but not supported by some others such as arm. So for some functions,
a no-op version should be available. Currently it's generic_access_phys,
which is referenced by some other modules.

Signed-off-by: Wang Wenhu <wenhu.wang@hotmail.com>
---
v2:
 - Added IS_ENABLED(CONFIG_HAVE_IOREMAP_PROT) condition in __access_remote_vm
 - Added generic_access_phys() function with no-op in mm/memory.c instead of the 
 former one of "static inline" in include/linux/mm.h
Former: https://lore.kernel.org/linux-mm/YqMRtWAH5fIWsLQB@kroah.com/T/
---
 drivers/char/mem.c          |  2 --
 drivers/fpga/dfl-afu-main.c |  2 --
 drivers/pci/mmap.c          |  2 --
 drivers/uio/uio.c           |  2 --
 mm/memory.c                 | 13 +++++++++----
 5 files changed, 9 insertions(+), 12 deletions(-)

Comments

Christoph Hellwig June 15, 2022, 6:49 a.m. UTC | #1 
Did you verify that all architectures actually provide a ioremap_prot
prototype?
The header situation for ioremap* is a mess unfortunately.
kernel test robot June 22, 2022, 2:22 a.m. UTC | #2 
Hi Wang,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Wang-Wenhu/mm-eliminate-ifdef-of-HAVE_IOREMAP_PROT-in-c-files/20220615-140135
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
config: arm-randconfig-s032-20220622 (https://download.01.org/0day-ci/archive/20220622/202206221053.GV7BYwqL-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 11.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-31-g4880bd19-dirty
        # https://github.com/intel-lab-lkp/linux/commit/b20efcc877829b6f416cf111bd5ad2b13a0cd08e
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Wang-Wenhu/mm-eliminate-ifdef-of-HAVE_IOREMAP_PROT-in-c-files/20220615-140135
        git checkout b20efcc877829b6f416cf111bd5ad2b13a0cd08e
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=arm SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

>> arm-linux-gnueabi-ld: drivers/char/mem.o:(.rodata+0x144): undefined reference to `generic_access_phys'
kernel test robot June 22, 2022, 4:13 a.m. UTC | #3 
Hi Wang,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Wang-Wenhu/mm-eliminate-ifdef-of-HAVE_IOREMAP_PROT-in-c-files/20220615-140135
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
config: m68k-buildonly-randconfig-r001-20220622 (https://download.01.org/0day-ci/archive/20220622/202206221102.w7hylFXN-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 11.3.0
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
        # https://github.com/intel-lab-lkp/linux/commit/b20efcc877829b6f416cf111bd5ad2b13a0cd08e
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Wang-Wenhu/mm-eliminate-ifdef-of-HAVE_IOREMAP_PROT-in-c-files/20220615-140135
        git checkout b20efcc877829b6f416cf111bd5ad2b13a0cd08e
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

>> m68k-linux-ld: drivers/char/mem.o:(.rodata+0x37c): undefined reference to `generic_access_phys'
diff mbox series

Patch

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 84ca98ed1dad..40186a441e38 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -354,9 +354,7 @@  static inline int private_mapping_ok(struct vm_area_struct *vma)
 #endif
 
 static const struct vm_operations_struct mmap_mem_ops = {
-#ifdef CONFIG_HAVE_IOREMAP_PROT
 	.access = generic_access_phys
-#endif
 };
 
 static int mmap_mem(struct file *file, struct vm_area_struct *vma)
diff --git a/drivers/fpga/dfl-afu-main.c b/drivers/fpga/dfl-afu-main.c
index 7f621e96d3b8..833e14806c7a 100644
--- a/drivers/fpga/dfl-afu-main.c
+++ b/drivers/fpga/dfl-afu-main.c
@@ -797,9 +797,7 @@  static long afu_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 }
 
 static const struct vm_operations_struct afu_vma_ops = {
-#ifdef CONFIG_HAVE_IOREMAP_PROT
 	.access = generic_access_phys,
-#endif
 };
 
 static int afu_mmap(struct file *filp, struct vm_area_struct *vma)
diff --git a/drivers/pci/mmap.c b/drivers/pci/mmap.c
index b8c9011987f4..1dcfabf80453 100644
--- a/drivers/pci/mmap.c
+++ b/drivers/pci/mmap.c
@@ -35,9 +35,7 @@  int pci_mmap_page_range(struct pci_dev *pdev, int bar,
 #endif
 
 static const struct vm_operations_struct pci_phys_vm_ops = {
-#ifdef CONFIG_HAVE_IOREMAP_PROT
 	.access = generic_access_phys,
-#endif
 };
 
 int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 43afbb7c5ab9..c9205a121007 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -719,9 +719,7 @@  static int uio_mmap_logical(struct vm_area_struct *vma)
 }
 
 static const struct vm_operations_struct uio_physical_vm_ops = {
-#ifdef CONFIG_HAVE_IOREMAP_PROT
 	.access = generic_access_phys,
-#endif
 };
 
 static int uio_mmap_physical(struct vm_area_struct *vma)
diff --git a/mm/memory.c b/mm/memory.c
index 7a089145cad4..7c0e59085456 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5413,6 +5413,13 @@  int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
 	return ret;
 }
 EXPORT_SYMBOL_GPL(generic_access_phys);
+#else
+int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
+			void *buf, int len, int write)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(generic_access_phys);
 #endif
 
 /*
@@ -5437,9 +5444,8 @@  int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf,
 		ret = get_user_pages_remote(mm, addr, 1,
 				gup_flags, &page, &vma, NULL);
 		if (ret <= 0) {
-#ifndef CONFIG_HAVE_IOREMAP_PROT
-			break;
-#else
+			if (!IS_ENABLED(CONFIG_HAVE_IOREMAP_PROT))
+				break;
 			/*
 			 * Check if this is a VM_IO | VM_PFNMAP VMA, which
 			 * we can access using slightly different code.
@@ -5453,7 +5459,6 @@  int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf,
 			if (ret <= 0)
 				break;
 			bytes = ret;
-#endif
 		} else {
 			bytes = len;
 			offset = addr & (PAGE_SIZE-1);