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@xxxxxxxxxxx> --- 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@xxxxxxxxx/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(-) 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); -- 2.25.1
