freebsd-dev/config/kernel-vfs-rw-iterate.m4
Richard Yao 1d53657bf5 Fix incompatibility with Reiser4 patched kernels
In ZFSOnLinux, our sources and build system are self contained such that
we do not need to make changes to the Linux kernel sources. Reiser4 on
the other hand exists solely as a kernel tree patch and opts to make
changes to the kernel rather than adapt to it. After Linux 4.1 made a
VFS change that replaced new_sync_read with do_sync_read, Reiser4's
maintainer decided to modify the kernel VFS to export the old function.
This caused our autotools check to misidentify the kernel API as
predating Linux 4.1 on kernels that have been patched with Reiser4
support, which breaks our build.

Reiser4 really should be patched to stop doing this, but lets modify our
check to be more strict to help the affected users of both filesystems.

Also, we were not checking the types of arguments and return value of
new_sync_read() and new_sync_write() . Lets fix that too.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes #6241 
Closes #7021
2018-01-09 16:18:19 -08:00

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dnl #
dnl # Linux 3.16 API
dnl #
AC_DEFUN([ZFS_AC_KERNEL_VFS_RW_ITERATE],
[AC_MSG_CHECKING([whether fops->read/write_iter() are available])
ZFS_LINUX_TRY_COMPILE([
#include <linux/fs.h>
ssize_t test_read(struct kiocb *kiocb, struct iov_iter *to)
{ return 0; }
ssize_t test_write(struct kiocb *kiocb, struct iov_iter *from)
{ return 0; }
static const struct file_operations
fops __attribute__ ((unused)) = {
.read_iter = test_read,
.write_iter = test_write,
};
],[
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_VFS_RW_ITERATE, 1,
[fops->read/write_iter() are available])
ZFS_AC_KERNEL_NEW_SYNC_READ
],[
AC_MSG_RESULT(no)
])
])
dnl #
dnl # Linux 4.1 API
dnl #
AC_DEFUN([ZFS_AC_KERNEL_NEW_SYNC_READ],
[AC_MSG_CHECKING([whether new_sync_read/write() are available])
ZFS_LINUX_TRY_COMPILE([
#include <linux/fs.h>
],[
ssize_t ret __attribute__ ((unused));
struct file *filp = NULL;
char __user *rbuf = NULL;
const char __user *wbuf = NULL;
size_t len = 0;
loff_t ppos;
ret = new_sync_read(filp, rbuf, len, &ppos);
ret = new_sync_write(filp, wbuf, len, &ppos);
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_NEW_SYNC_READ, 1,
[new_sync_read()/new_sync_write() are available])
],[
AC_MSG_RESULT(no)
])
])
dnl #
dnl # Linux 4.1.x API
dnl #
AC_DEFUN([ZFS_AC_KERNEL_GENERIC_WRITE_CHECKS],
[AC_MSG_CHECKING([whether generic_write_checks() takes kiocb])
ZFS_LINUX_TRY_COMPILE([
#include <linux/fs.h>
],[
struct kiocb *iocb = NULL;
struct iov_iter *iov = NULL;
generic_write_checks(iocb, iov);
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_GENERIC_WRITE_CHECKS_KIOCB, 1,
[generic_write_checks() takes kiocb])
],[
AC_MSG_RESULT(no)
])
])