From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:42956 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752504AbdHOOoe (ORCPT ); Tue, 15 Aug 2017 10:44:34 -0400 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v7FEeTYB130297 for ; Tue, 15 Aug 2017 10:44:33 -0400 Received: from e23smtp07.au.ibm.com (e23smtp07.au.ibm.com [202.81.31.140]) by mx0a-001b2d01.pphosted.com with ESMTP id 2cc22sk526-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 15 Aug 2017 10:44:32 -0400 Received: from localhost by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 16 Aug 2017 00:44:30 +1000 From: Mimi Zohar To: Christoph Hellwig , Al Viro Cc: Matthew Garrett , Mimi Zohar , James Morris , linux-fsdevel@vger.kernel.org, linux-ima-devel@lists.sourceforge.net, linux-security-module@vger.kernel.org, Matthew Garrett Subject: [PATCH v6 1/6] libfs: define simple_read_iter_from_buffer Date: Tue, 15 Aug 2017 10:43:52 -0400 In-Reply-To: <1502808237-2035-1-git-send-email-zohar@linux.vnet.ibm.com> References: <1502808237-2035-1-git-send-email-zohar@linux.vnet.ibm.com> Message-Id: <1502808237-2035-2-git-send-email-zohar@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: In preparation for defining an integrity_read file operation method for efivarfs, define a simple_read_iter_from_buffer() function. (Based on Al's code as posted in thread.) Suggested-by: Al Viro Signed-off-by: Mimi Zohar Cc: Matthew Garrett --- Changelog v6: - defined as a separate patch fs/libfs.c | 32 ++++++++++++++++++++++++++++++++ include/linux/fs.h | 2 ++ 2 files changed, 34 insertions(+) diff --git a/fs/libfs.c b/fs/libfs.c index 3aabe553fc45..b6e304c6828b 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -16,6 +16,7 @@ #include #include #include /* sync_mapping_buffers */ +#include #include @@ -676,6 +677,37 @@ ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, EXPORT_SYMBOL(simple_write_to_buffer); /** + * simple_read_iter_from_buffer - copy data from the buffer to user space + * @iocb: struct containing the file, the current position and other info + * @to: the user space buffer to read to + * @from: the buffer to read from + * @available: the size of the buffer + * + * The simple_read_iter_from_buffer() function reads up to @available bytes + * from the current buffer into the user space buffer. + * + * On success, the current buffer offset is advanced by the number of bytes + * read, or a negative value is returned on error. + **/ +ssize_t simple_read_iter_from_buffer(struct kiocb *iocb, struct iov_iter *to, + const void *from, size_t available) +{ + loff_t pos = iocb->ki_pos; + size_t ret; + + if (pos < 0) + return -EINVAL; + if (pos >= available) + return 0; + ret = copy_to_iter(from + pos, available - pos, to); + if (!ret && iov_iter_count(to)) + return -EFAULT; + iocb->ki_pos = pos + ret; + return ret; +} +EXPORT_SYMBOL(simple_read_iter_from_buffer); + +/** * memory_read_from_buffer - copy data from the buffer * @to: the kernel space buffer to read to * @count: the maximum number of bytes to read diff --git a/include/linux/fs.h b/include/linux/fs.h index 6e1fd5d21248..fdec9b763b54 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3097,6 +3097,8 @@ extern void simple_release_fs(struct vfsmount **mount, int *count); extern ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, const void *from, size_t available); +extern ssize_t simple_read_iter_from_buffer(struct kiocb *iocb, + struct iov_iter *to, const void *from, size_t available); extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, const void __user *from, size_t count); -- 2.7.4