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From: Christoph Hellwig <hch@lst.de>
To: Linus Torvalds <torvalds@linux-foundation.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Michael Ellerman <mpe@ellerman.id.au>,
	x86@kernel.org
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
	Luis Chamberlain <mcgrof@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 03/14] proc: add a read_iter method to proc proc_ops
Date: Thu,  3 Sep 2020 16:22:31 +0200	[thread overview]
Message-ID: <20200903142242.925828-4-hch@lst.de> (raw)
In-Reply-To: <20200903142242.925828-1-hch@lst.de>

This will allow proc files to implement iter read semantics.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/proc/inode.c         | 53 ++++++++++++++++++++++++++++++++++++++---
 include/linux/proc_fs.h |  1 +
 2 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 93dd2045737504..58c075e2a452d6 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -297,6 +297,21 @@ static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
 	return rv;
 }
 
+static ssize_t proc_reg_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct proc_dir_entry *pde = PDE(file_inode(iocb->ki_filp));
+	ssize_t ret;
+
+	if (pde_is_permanent(pde))
+		return pde->proc_ops->proc_read_iter(iocb, iter);
+
+	if (!use_pde(pde))
+		return -EIO;
+	ret = pde->proc_ops->proc_read_iter(iocb, iter);
+	unuse_pde(pde);
+	return ret;
+}
+
 static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos)
 {
 	typeof_member(struct proc_ops, proc_read) read;
@@ -578,6 +593,18 @@ static const struct file_operations proc_reg_file_ops = {
 	.release	= proc_reg_release,
 };
 
+static const struct file_operations proc_iter_file_ops = {
+	.llseek		= proc_reg_llseek,
+	.read_iter	= proc_reg_read_iter,
+	.write		= proc_reg_write,
+	.poll		= proc_reg_poll,
+	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
+	.mmap		= proc_reg_mmap,
+	.get_unmapped_area = proc_reg_get_unmapped_area,
+	.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,
@@ -591,6 +618,19 @@ static const struct file_operations proc_reg_file_ops_compat = {
 	.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,
+	.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,
+	.open		= proc_reg_open,
+	.release	= proc_reg_release,
+};
 #endif
 
 static void proc_put_link(void *p)
@@ -642,10 +682,17 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
 
 	if (S_ISREG(inode->i_mode)) {
 		inode->i_op = de->proc_iops;
-		inode->i_fop = &proc_reg_file_ops;
+		if (de->proc_ops->proc_read_iter)
+			inode->i_fop = &proc_iter_file_ops;
+		else
+			inode->i_fop = &proc_reg_file_ops;
 #ifdef CONFIG_COMPAT
-		if (de->proc_ops->proc_compat_ioctl)
-			inode->i_fop = &proc_reg_file_ops_compat;
+		if (de->proc_ops->proc_compat_ioctl) {
+			if (de->proc_ops->proc_read_iter)
+				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;
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 2df965cd09742d..270cab43ca3dad 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -30,6 +30,7 @@ struct proc_ops {
 	unsigned int proc_flags;
 	int	(*proc_open)(struct inode *, struct file *);
 	ssize_t	(*proc_read)(struct file *, char __user *, size_t, loff_t *);
+	ssize_t (*proc_read_iter)(struct kiocb *, struct iov_iter *);
 	ssize_t	(*proc_write)(struct file *, const char __user *, size_t, loff_t *);
 	loff_t	(*proc_lseek)(struct file *, loff_t, int);
 	int	(*proc_release)(struct inode *, struct file *);
-- 
2.28.0


  parent reply	other threads:[~2020-09-03 14:26 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-03 14:22 remove the last set_fs() in common code, and remove it for x86 and powerpc v3 Christoph Hellwig
2020-09-03 14:22 ` [PATCH 01/14] proc: remove a level of indentation in proc_get_inode Christoph Hellwig
2020-09-03 14:22 ` [PATCH 02/14] proc: cleanup the compat vs no compat file ops Christoph Hellwig
2020-09-03 14:22 ` Christoph Hellwig [this message]
2020-09-03 14:22 ` [PATCH 04/14] sysctl: Convert to iter interfaces Christoph Hellwig
2020-09-03 14:22 ` [PATCH 05/14] fs: don't allow kernel reads and writes without iter ops Christoph Hellwig
2020-10-01 22:38   ` Eric Biggers
2020-10-01 22:40     ` Al Viro
2020-10-02 16:27       ` Linus Torvalds
2020-10-09 22:06         ` Eric Biggers
2020-10-10  1:03           ` Linus Torvalds
2020-10-10  1:19             ` Eric Biggers
2020-10-10  1:29               ` Linus Torvalds
2020-10-10  1:55                 ` Alexander Viro
2020-10-14  5:51                   ` Christoph Hellwig
2020-09-03 14:22 ` [PATCH 06/14] fs: don't allow splice read/write without explicit ops Christoph Hellwig
2020-09-03 14:22 ` [PATCH 07/14] uaccess: add infrastructure for kernel builds with set_fs() Christoph Hellwig
2020-09-03 14:22 ` [PATCH 08/14] test_bitmap: remove user bitmap tests Christoph Hellwig
2020-09-03 14:22 ` [PATCH 09/14] lkdtm: remove set_fs-based tests Christoph Hellwig
2020-09-03 14:22 ` [PATCH 10/14] x86: move PAGE_OFFSET, TASK_SIZE & friends to page_{32,64}_types.h Christoph Hellwig
2020-09-03 14:22 ` [PATCH 11/14] x86: make TASK_SIZE_MAX usable from assembly code Christoph Hellwig
2020-09-03 14:22 ` [PATCH 12/14] x86: remove address space overrides using set_fs() Christoph Hellwig
2020-09-03 21:30   ` David Laight
2020-09-03 23:25     ` Linus Torvalds
2020-09-04  7:59       ` David Laight
2020-09-04  2:55   ` Al Viro
2020-09-04  4:41     ` Al Viro
2020-09-04  6:38     ` Christoph Hellwig
2020-09-04  7:47       ` Christoph Hellwig
2020-09-03 14:22 ` [PATCH 13/14] powerpc: use non-set_fs based maccess routines Christoph Hellwig
2020-09-03 14:22 ` [PATCH 14/14] powerpc: remove address space overrides using set_fs() Christoph Hellwig
2020-09-03 15:43   ` Christophe Leroy
2020-09-03 15:49     ` Christoph Hellwig
2020-09-03 15:56       ` Christoph Hellwig
2020-09-03 16:03         ` Christophe Leroy
2020-09-03 14:28 ` remove the last set_fs() in common code, and remove it for x86 and powerpc v3 Al Viro
2020-09-03 14:30   ` Christoph Hellwig
2020-09-03 14:36     ` Al Viro
2020-09-03 14:40       ` Christoph Hellwig
2020-09-09 17:31   ` Linus Torvalds
2020-09-09 18:40     ` Segher Boessenkool
2020-09-09 21:33       ` Linus Torvalds
2020-09-10  8:04         ` David Laight
2020-09-10  8:13           ` Christophe Leroy
2020-09-10  9:26             ` David Laight
2020-09-10 12:26               ` David Laight
2020-09-10 15:20                 ` Segher Boessenkool
2020-09-10 15:31                   ` David Laight
2020-09-10 17:15                     ` Segher Boessenkool
2020-09-10 15:16               ` Segher Boessenkool
2020-09-10 15:44         ` Segher Boessenkool
2020-09-03 15:49 ` Linus Torvalds
2020-09-04  6:00 ` Ingo Molnar
2020-09-04 17:58   ` Alexey Dobriyan
2020-09-04 18:42     ` Linus Torvalds
2020-09-04 21:01     ` David Laight
2020-09-05  7:16       ` Christophe Leroy
2020-09-05 10:13         ` David Laight

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