seq_file: add seq_read_iter (d4d50710) · Commits · 戴 / test

fs/seq_file.c

+32 −13

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@
		#include <linux/mm.h>
		#include <linux/printk.h>
		#include <linux/string_helpers.h>
		#include <linux/uio.h>

		#include <linux/uaccess.h>
		#include <asm/page.h>
		@@ -146,7 +147,28 @@ Eoverflow:
		*/
		ssize_t seq_read(struct file file, char __user buf, size_t size, loff_t *ppos)
		{
		struct seq_file *m = file->private_data;
		struct iovec iov = { .iov_base = buf, .iov_len = size};
		struct kiocb kiocb;
		struct iov_iter iter;
		ssize_t ret;

		init_sync_kiocb(&kiocb, file);
		iov_iter_init(&iter, READ, &iov, 1, size);

		kiocb.ki_pos = *ppos;
		ret = seq_read_iter(&kiocb, &iter);
		*ppos = kiocb.ki_pos;
		return ret;
		}
		EXPORT_SYMBOL(seq_read);

		/*
		* Ready-made ->f_op->read_iter()
		*/
		ssize_t seq_read_iter(struct kiocb iocb, struct iov_iter iter)
		{
		struct seq_file *m = iocb->ki_filp->private_data;
		size_t size = iov_iter_count(iter);
		size_t copied = 0;
		size_t n;
		void *p;
		@@ -158,14 +180,14 @@ ssize_t seq_read(struct file file, char __user buf, size_t size, loff_t *ppos)
		* if request is to read from zero offset, reset iterator to first
		* record as it might have been already advanced by previous requests
		*/
		if (*ppos == 0) {
		if (iocb->ki_pos == 0) {
		m->index = 0;
		m->count = 0;
		}

		/* Don't assume ppos is where we left it /
		if (unlikely(*ppos != m->read_pos)) {
		while ((err = traverse(m, *ppos)) == -EAGAIN)
		/* Don't assume ki_pos is where we left it */
		if (unlikely(iocb->ki_pos != m->read_pos)) {
		while ((err = traverse(m, iocb->ki_pos)) == -EAGAIN)
		;
		if (err) {
		/* With prejudice... */
		@@ -174,7 +196,7 @@ ssize_t seq_read(struct file file, char __user buf, size_t size, loff_t *ppos)
		m->count = 0;
		goto Done;
		} else {
		m->read_pos = *ppos;
		m->read_pos = iocb->ki_pos;
		}
		}

		@@ -187,13 +209,11 @@ ssize_t seq_read(struct file file, char __user buf, size_t size, loff_t *ppos)
		/* if not empty - flush it first */
		if (m->count) {
		n = min(m->count, size);
		err = copy_to_user(buf, m->buf + m->from, n);
		if (err)
		if (copy_to_iter(m->buf + m->from, n, iter) != n)
		goto Efault;
		m->count -= n;
		m->from += n;
		size -= n;
		buf += n;
		copied += n;
		if (!size)
		goto Done;
		@@ -254,8 +274,7 @@ Fill:
		}
		m->op->stop(m, p);
		n = min(m->count, size);
		err = copy_to_user(buf, m->buf, n);
		if (err)
		if (copy_to_iter(m->buf, n, iter) != n)
		goto Efault;
		copied += n;
		m->count -= n;
		@@ -264,7 +283,7 @@ Done:
		if (!copied)
		copied = err;
		else {
		*ppos += copied;
		iocb->ki_pos += copied;
		m->read_pos += copied;
		}
		mutex_unlock(&m->lock);
		@@ -276,7 +295,7 @@ Efault:
		err = -EFAULT;
		goto Done;
		}
		EXPORT_SYMBOL(seq_read);
		EXPORT_SYMBOL(seq_read_iter);

		/**
		* seq_lseek - ->llseek() method for sequential files.

include/linux/seq_file.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -107,6 +107,7 @@ void seq_pad(struct seq_file *m, char c);
		char mangle_path(char s, const char p, const char esc);
		int seq_open(struct file , const struct seq_operations );
		ssize_t seq_read(struct file , char __user , size_t, loff_t *);
		ssize_t seq_read_iter(struct kiocb iocb, struct iov_iter iter);
		loff_t seq_lseek(struct file *, loff_t, int);
		int seq_release(struct inode , struct file );
		int seq_write(struct seq_file seq, const void data, size_t len);

Original line number	Diff line number	Diff line
		@@ -107,6 +107,7 @@ void seq_pad(struct seq_file *m, char c);
		char mangle_path(char s, const char p, const char esc);
		int seq_open(struct file , const struct seq_operations );
		ssize_t seq_read(struct file , char __user , size_t, loff_t *);
		ssize_t seq_read_iter(struct kiocb iocb, struct iov_iter iter);
		loff_t seq_lseek(struct file *, loff_t, int);
		int seq_release(struct inode , struct file );
		int seq_write(struct seq_file seq, const void data, size_t len);

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