LU-12438 llite: vfs_read/write removed, use kernel_read/write

As of Linux 4.14 the vfs_read() is no longer available
to kernel modules. The kernel_read() function calls
vfs_read() and will continue to be available.

Adding a configure test to use kernel_read() as the
function signature changed in 4.14 to match the other file I/O
helpers.

Also remove vfs_write() in favor of kernel_write() wrapper
cfs_kernel_write().

Fixes: f172b1168857 ("LU-10092 llite: Add persistent cache on client")
Signed-off-by: Shaun Tancheff <stancheff@cray.com>
Signed-off-by: Qian Yingjin <qian@ddn.com>
Change-Id: I5e5fce0e6644ba750169f3bf11ac5c98525da0a7
Reviewed-on: https://review.whamcloud.com/35223
Tested-by: Jenkins
Reviewed-by: Wang Shilong <wshilong@ddn.com>
Reviewed-by: Li Xi <lixi@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Petros Koutoupis <pkoutoupis@cray.com>

diff --git a/libcfs/autoconf/lustre-libcfs.m4 b/libcfs/autoconf/lustre-libcfs.m4
index 543b989..c1cb43b 100644 (file)
--- a/libcfs/autoconf/lustre-libcfs.m4
+++ b/libcfs/autoconf/lustre-libcfs.m4
@@ -1004,6 +1004,29 @@ EXTRA_KCFLAGS="$tmp_flags"
 ]) # LIBCFS_NEW_KERNEL_WRITE
 
 #
+# LIBCFS_NEW_KERNEL_WRITE
+#
+# 4.14 commit bdd1d2d3d251c65b74ac4493e08db18971c09240 changed
+# the signature of kernel_read to match other read/write helpers
+# and place offset last.
+#
+AC_DEFUN([LIBCFS_NEW_KERNEL_READ], [
+tmp_flags="$EXTRA_KCFLAGS"
+EXTRA_KCFLAGS="-Werror"
+LB_CHECK_COMPILE([if 'kernel_read()' has loff_t *pos as last parameter],
+kernel_read, [
+       #include <linux/fs.h>
+       ],[
+       loff_t pos = 0;
+       kernel_read(NULL, NULL, 0, &pos);
+],[
+       AC_DEFINE(HAVE_KERNEL_READ_LAST_POSP, 1,
+               [kernel_read() signature ends with loff_t *pos])
+])
+EXTRA_KCFLAGS="$tmp_flags"
+]) # LIBCFS_NEW_KERNEL_READ
+
+#
 # LIBCFS_DEFINE_TIMER
 #
 # Kernel version 4.14 commit 1d27e3e2252ba9d949ca82fbdb73cde102cb2067
@@ -1196,6 +1219,7 @@ LIBCFS_WAIT_QUEUE_ENTRY
 # 4.14
 LIBCFS_DEFINE_TIMER
 LIBCFS_NEW_KERNEL_WRITE
+LIBCFS_NEW_KERNEL_READ
 LIBCFS_EXPORT_SAVE_STACK_TRACE_TSK
 # 4.15
 LIBCFS_TIMER_SETUP

diff --git a/libcfs/include/libcfs/linux/linux-misc.h b/libcfs/include/libcfs/linux/linux-misc.h
index 230d8d4..524bf40 100644 (file)
--- a/libcfs/include/libcfs/linux/linux-misc.h
+++ b/libcfs/include/libcfs/linux/linux-misc.h
@@ -115,6 +115,8 @@ int cfs_get_environ(const char *key, char *value, int *val_len);
 
 int cfs_kernel_write(struct file *filp, const void *buf, size_t count,
                     loff_t *pos);
+ssize_t cfs_kernel_read(struct file *file, void *buf, size_t count,
+                       loff_t *pos);
 
 /*
  * For RHEL6 struct kernel_parm_ops doesn't exist. Also

diff --git a/libcfs/libcfs/linux/linux-prim.c b/libcfs/libcfs/linux/linux-prim.c
index 4f07340..f263e9e 100644 (file)
--- a/libcfs/libcfs/linux/linux-prim.c
+++ b/libcfs/libcfs/linux/linux-prim.c
@@ -120,6 +120,20 @@ int cfs_kernel_write(struct file *filp, const void *buf, size_t count,
 }
 EXPORT_SYMBOL(cfs_kernel_write);
 
+ssize_t cfs_kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
+{
+#ifdef HAVE_KERNEL_READ_LAST_POSP
+       return kernel_read(file, buf, count, pos);
+#else
+       ssize_t size = kernel_read(file, *pos, buf, count);
+
+       if (size > 0)
+               *pos += size;
+       return size;
+#endif
+}
+EXPORT_SYMBOL(cfs_kernel_read);
+
 #ifndef HAVE_KSET_FIND_OBJ
 struct kobject *kset_find_obj(struct kset *kset, const char *name)
 {

diff --git a/lustre/llite/pcc.c b/lustre/llite/pcc.c
index fcebed4..c779c72 100644 (file)
--- a/lustre/llite/pcc.c
+++ b/lustre/llite/pcc.c
@@ -2168,7 +2168,7 @@ static int pcc_filp_write(struct file *filp, const void *buf, ssize_t count,
        while (count > 0) {
                ssize_t size;
 
-               size = vfs_write(filp, (const void __user *)buf, count, offset);
+               size = cfs_kernel_write(filp, buf, count, offset);
                if (size < 0)
                        return size;
                count -= size;
@@ -2181,7 +2181,6 @@ static int pcc_copy_data(struct file *src, struct file *dst)
 {
        int rc = 0;
        ssize_t rc2;
-       mm_segment_t oldfs;
        loff_t pos, offset = 0;
        size_t buf_len = 1048576;
        void *buf;
@@ -2192,25 +2191,22 @@ static int pcc_copy_data(struct file *src, struct file *dst)
        if (buf == NULL)
                RETURN(-ENOMEM);
 
-       oldfs = get_fs();
-       set_fs(KERNEL_DS);
        while (1) {
                pos = offset;
-               rc2 = vfs_read(src, (void __user *)buf, buf_len, &pos);
+               rc2 = cfs_kernel_read(src, buf, buf_len, &pos);
                if (rc2 < 0)
-                       GOTO(out_fs, rc = rc2);
+                       GOTO(out_free, rc = rc2);
                else if (rc2 == 0)
                        break;
 
                pos = offset;
                rc = pcc_filp_write(dst, buf, rc2, &pos);
                if (rc < 0)
-                       GOTO(out_fs, rc);
+                       GOTO(out_free, rc);
                offset += rc2;
        }
 
-out_fs:
-       set_fs(oldfs);
+out_free:
        OBD_FREE_LARGE(buf, buf_len);
        RETURN(rc);
 }