[PATCH RESEND v2 01/23] proc: drop the compat file operations

[Christian Brauner <brauner@kernel.org>]

procfs has both sets of file operations twice, with and without
->compat_ioctl(), and picks the one with it for entries that have
->proc_compat_ioctl(). That's from commit 778f3dd5a13c ("Fix procfs
compat_ioctl regression") when a file without ->compat_ioctl() went
through the translation tables in fs/compat_ioctl.c and one with it
didn't. Those tables are gone since commit 77b9040195de ("compat_ioctl:
simplify the implementation"). compat_sys_ioctl() answers -ENOTTY for a
file without ->compat_ioctl() now, which is what
proc_reg_compat_ioctl() answers for an entry without
->proc_compat_ioctl().

So always set ->compat_ioctl() and drop the second set of file
operations and the flag that picked it.

No functional changes.

Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
---
 fs/proc/generic.c       |  4 ----
 fs/proc/inode.c         | 45 +++------------------------------------------
 fs/proc/internal.h      |  9 ---------
 include/linux/proc_fs.h |  1 -
 4 files changed, 3 insertions(+), 56 deletions(-)

diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 9a0a2fcac7c7..e7264f0cf5ab 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -446,10 +446,6 @@ static void pde_set_flags(struct proc_dir_entry *pde)
 		pde->flags |= PROC_ENTRY_PERMANENT;
 	if (proc_ops->proc_read_iter)
 		pde->flags |= PROC_ENTRY_proc_read_iter;
-#ifdef CONFIG_COMPAT
-	if (proc_ops->proc_compat_ioctl)
-		pde->flags |= PROC_ENTRY_proc_compat_ioctl;
-#endif
 	if (proc_ops->proc_lseek)
 		pde->flags |= PROC_ENTRY_proc_lseek;
 }
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 2d65f3c8ec03..18f6490bfe77 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -410,6 +410,8 @@ static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned
 	}
 	return rv;
 }
+#else
+#define proc_reg_compat_ioctl NULL
 #endif
 
 static int pde_mmap(struct proc_dir_entry *pde, struct file *file, struct vm_area_struct *vma)
@@ -569,6 +571,7 @@ static const struct file_operations proc_reg_file_ops = {
 	.write		= proc_reg_write,
 	.poll		= proc_reg_poll,
 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
+	.compat_ioctl	= proc_reg_compat_ioctl,
 	.mmap		= proc_reg_mmap,
 	.get_unmapped_area = proc_reg_get_unmapped_area,
 #ifndef CONFIG_MMU
@@ -585,39 +588,6 @@ static const struct file_operations proc_iter_file_ops = {
 	.splice_read	= copy_splice_read,
 	.poll		= proc_reg_poll,
 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
-	.mmap		= proc_reg_mmap,
-	.get_unmapped_area = proc_reg_get_unmapped_area,
-#ifndef CONFIG_MMU
-	.mmap_capabilities = proc_reg_mmap_capabilities,
-#endif
-	.open		= proc_reg_open,
-	.release	= proc_reg_release,
-};
-
-#ifdef CONFIG_COMPAT
-static const struct file_operations proc_reg_file_ops_compat = {
-	.llseek		= proc_reg_llseek,
-	.read		= proc_reg_read,
-	.write		= proc_reg_write,
-	.poll		= proc_reg_poll,
-	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
-	.compat_ioctl	= proc_reg_compat_ioctl,
-	.mmap		= proc_reg_mmap,
-	.get_unmapped_area = proc_reg_get_unmapped_area,
-#ifndef CONFIG_MMU
-	.mmap_capabilities = proc_reg_mmap_capabilities,
-#endif
-	.open		= proc_reg_open,
-	.release	= proc_reg_release,
-};
-
-static const struct file_operations proc_iter_file_ops_compat = {
-	.llseek		= proc_reg_llseek,
-	.read_iter	= proc_reg_read_iter,
-	.splice_read	= copy_splice_read,
-	.write		= proc_reg_write,
-	.poll		= proc_reg_poll,
-	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
 	.compat_ioctl	= proc_reg_compat_ioctl,
 	.mmap		= proc_reg_mmap,
 	.get_unmapped_area = proc_reg_get_unmapped_area,
@@ -627,7 +597,6 @@ static const struct file_operations proc_iter_file_ops_compat = {
 	.open		= proc_reg_open,
 	.release	= proc_reg_release,
 };
-#endif
 
 static const char *proc_get_link(struct dentry *dentry,
 				 struct inode *inode,
@@ -683,14 +652,6 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
 			inode->i_fop = &proc_iter_file_ops;
 		else
 			inode->i_fop = &proc_reg_file_ops;
-#ifdef CONFIG_COMPAT
-		if (pde_has_proc_compat_ioctl(de)) {
-			if (pde_has_proc_read_iter(de))
-				inode->i_fop = &proc_iter_file_ops_compat;
-			else
-				inode->i_fop = &proc_reg_file_ops_compat;
-		}
-#endif
 	} else if (S_ISDIR(inode->i_mode)) {
 		inode->i_op = de->proc_iops;
 		inode->i_fop = de->proc_dir_ops;
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 04f7ce2b24ed..268a0523be12 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -92,15 +92,6 @@ static inline bool pde_has_proc_read_iter(const struct proc_dir_entry *pde)
 	return pde->flags & PROC_ENTRY_proc_read_iter;
 }
 
-static inline bool pde_has_proc_compat_ioctl(const struct proc_dir_entry *pde)
-{
-#ifdef CONFIG_COMPAT
-	return pde->flags & PROC_ENTRY_proc_compat_ioctl;
-#else
-	return false;
-#endif
-}
-
 static inline bool pde_has_proc_lseek(const struct proc_dir_entry *pde)
 {
 	return pde->flags & PROC_ENTRY_proc_lseek;
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 47d7deaeed8f..6ad5150020bf 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -26,7 +26,6 @@ enum {
 #endif
 
 	PROC_ENTRY_proc_read_iter	= 1U << 1,
-	PROC_ENTRY_proc_compat_ioctl	= 1U << 2,
 	PROC_ENTRY_proc_lseek		= 1U << 3,
 
 	PROC_ENTRY_FORCE_LOOKUP		= 1U << 7,

-- 
2.53.0