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linux-next/net/sunrpc/xprtmultipath.c
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00

497 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Multipath support for RPC
*
* Copyright (c) 2015, 2016, Primary Data, Inc. All rights reserved.
*
* Trond Myklebust <trond.myklebust@primarydata.com>
*
*/
#include <linux/types.h>
#include <linux/kref.h>
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/rculist.h>
#include <linux/slab.h>
#include <asm/cmpxchg.h>
#include <linux/spinlock.h>
#include <linux/sunrpc/xprt.h>
#include <linux/sunrpc/addr.h>
#include <linux/sunrpc/xprtmultipath.h>
typedef struct rpc_xprt *(*xprt_switch_find_xprt_t)(struct list_head *head,
const struct rpc_xprt *cur);
static const struct rpc_xprt_iter_ops rpc_xprt_iter_singular;
static const struct rpc_xprt_iter_ops rpc_xprt_iter_roundrobin;
static const struct rpc_xprt_iter_ops rpc_xprt_iter_listall;
static void xprt_switch_add_xprt_locked(struct rpc_xprt_switch *xps,
struct rpc_xprt *xprt)
{
if (unlikely(xprt_get(xprt) == NULL))
return;
list_add_tail_rcu(&xprt->xprt_switch, &xps->xps_xprt_list);
smp_wmb();
if (xps->xps_nxprts == 0)
xps->xps_net = xprt->xprt_net;
xps->xps_nxprts++;
}
/**
* rpc_xprt_switch_add_xprt - Add a new rpc_xprt to an rpc_xprt_switch
* @xps: pointer to struct rpc_xprt_switch
* @xprt: pointer to struct rpc_xprt
*
* Adds xprt to the end of the list of struct rpc_xprt in xps.
*/
void rpc_xprt_switch_add_xprt(struct rpc_xprt_switch *xps,
struct rpc_xprt *xprt)
{
if (xprt == NULL)
return;
spin_lock(&xps->xps_lock);
if ((xps->xps_net == xprt->xprt_net || xps->xps_net == NULL) &&
!rpc_xprt_switch_has_addr(xps, (struct sockaddr *)&xprt->addr))
xprt_switch_add_xprt_locked(xps, xprt);
spin_unlock(&xps->xps_lock);
}
static void xprt_switch_remove_xprt_locked(struct rpc_xprt_switch *xps,
struct rpc_xprt *xprt)
{
if (unlikely(xprt == NULL))
return;
xps->xps_nxprts--;
if (xps->xps_nxprts == 0)
xps->xps_net = NULL;
smp_wmb();
list_del_rcu(&xprt->xprt_switch);
}
/**
* rpc_xprt_switch_remove_xprt - Removes an rpc_xprt from a rpc_xprt_switch
* @xps: pointer to struct rpc_xprt_switch
* @xprt: pointer to struct rpc_xprt
*
* Removes xprt from the list of struct rpc_xprt in xps.
*/
void rpc_xprt_switch_remove_xprt(struct rpc_xprt_switch *xps,
struct rpc_xprt *xprt)
{
spin_lock(&xps->xps_lock);
xprt_switch_remove_xprt_locked(xps, xprt);
spin_unlock(&xps->xps_lock);
xprt_put(xprt);
}
/**
* xprt_switch_alloc - Allocate a new struct rpc_xprt_switch
* @xprt: pointer to struct rpc_xprt
* @gfp_flags: allocation flags
*
* On success, returns an initialised struct rpc_xprt_switch, containing
* the entry xprt. Returns NULL on failure.
*/
struct rpc_xprt_switch *xprt_switch_alloc(struct rpc_xprt *xprt,
gfp_t gfp_flags)
{
struct rpc_xprt_switch *xps;
xps = kmalloc(sizeof(*xps), gfp_flags);
if (xps != NULL) {
spin_lock_init(&xps->xps_lock);
kref_init(&xps->xps_kref);
xps->xps_nxprts = 0;
INIT_LIST_HEAD(&xps->xps_xprt_list);
xps->xps_iter_ops = &rpc_xprt_iter_singular;
xprt_switch_add_xprt_locked(xps, xprt);
}
return xps;
}
static void xprt_switch_free_entries(struct rpc_xprt_switch *xps)
{
spin_lock(&xps->xps_lock);
while (!list_empty(&xps->xps_xprt_list)) {
struct rpc_xprt *xprt;
xprt = list_first_entry(&xps->xps_xprt_list,
struct rpc_xprt, xprt_switch);
xprt_switch_remove_xprt_locked(xps, xprt);
spin_unlock(&xps->xps_lock);
xprt_put(xprt);
spin_lock(&xps->xps_lock);
}
spin_unlock(&xps->xps_lock);
}
static void xprt_switch_free(struct kref *kref)
{
struct rpc_xprt_switch *xps = container_of(kref,
struct rpc_xprt_switch, xps_kref);
xprt_switch_free_entries(xps);
kfree_rcu(xps, xps_rcu);
}
/**
* xprt_switch_get - Return a reference to a rpc_xprt_switch
* @xps: pointer to struct rpc_xprt_switch
*
* Returns a reference to xps unless the refcount is already zero.
*/
struct rpc_xprt_switch *xprt_switch_get(struct rpc_xprt_switch *xps)
{
if (xps != NULL && kref_get_unless_zero(&xps->xps_kref))
return xps;
return NULL;
}
/**
* xprt_switch_put - Release a reference to a rpc_xprt_switch
* @xps: pointer to struct rpc_xprt_switch
*
* Release the reference to xps, and free it once the refcount is zero.
*/
void xprt_switch_put(struct rpc_xprt_switch *xps)
{
if (xps != NULL)
kref_put(&xps->xps_kref, xprt_switch_free);
}
/**
* rpc_xprt_switch_set_roundrobin - Set a round-robin policy on rpc_xprt_switch
* @xps: pointer to struct rpc_xprt_switch
*
* Sets a round-robin default policy for iterators acting on xps.
*/
void rpc_xprt_switch_set_roundrobin(struct rpc_xprt_switch *xps)
{
if (READ_ONCE(xps->xps_iter_ops) != &rpc_xprt_iter_roundrobin)
WRITE_ONCE(xps->xps_iter_ops, &rpc_xprt_iter_roundrobin);
}
static
const struct rpc_xprt_iter_ops *xprt_iter_ops(const struct rpc_xprt_iter *xpi)
{
if (xpi->xpi_ops != NULL)
return xpi->xpi_ops;
return rcu_dereference(xpi->xpi_xpswitch)->xps_iter_ops;
}
static
void xprt_iter_no_rewind(struct rpc_xprt_iter *xpi)
{
}
static
void xprt_iter_default_rewind(struct rpc_xprt_iter *xpi)
{
WRITE_ONCE(xpi->xpi_cursor, NULL);
}
static
struct rpc_xprt *xprt_switch_find_first_entry(struct list_head *head)
{
return list_first_or_null_rcu(head, struct rpc_xprt, xprt_switch);
}
static
struct rpc_xprt *xprt_iter_first_entry(struct rpc_xprt_iter *xpi)
{
struct rpc_xprt_switch *xps = rcu_dereference(xpi->xpi_xpswitch);
if (xps == NULL)
return NULL;
return xprt_switch_find_first_entry(&xps->xps_xprt_list);
}
static
struct rpc_xprt *xprt_switch_find_current_entry(struct list_head *head,
const struct rpc_xprt *cur)
{
struct rpc_xprt *pos;
list_for_each_entry_rcu(pos, head, xprt_switch) {
if (cur == pos)
return pos;
}
return NULL;
}
static
struct rpc_xprt *xprt_iter_current_entry(struct rpc_xprt_iter *xpi)
{
struct rpc_xprt_switch *xps = rcu_dereference(xpi->xpi_xpswitch);
struct list_head *head;
if (xps == NULL)
return NULL;
head = &xps->xps_xprt_list;
if (xpi->xpi_cursor == NULL || xps->xps_nxprts < 2)
return xprt_switch_find_first_entry(head);
return xprt_switch_find_current_entry(head, xpi->xpi_cursor);
}
bool rpc_xprt_switch_has_addr(struct rpc_xprt_switch *xps,
const struct sockaddr *sap)
{
struct list_head *head;
struct rpc_xprt *pos;
if (xps == NULL || sap == NULL)
return false;
head = &xps->xps_xprt_list;
list_for_each_entry_rcu(pos, head, xprt_switch) {
if (rpc_cmp_addr_port(sap, (struct sockaddr *)&pos->addr)) {
pr_info("RPC: addr %s already in xprt switch\n",
pos->address_strings[RPC_DISPLAY_ADDR]);
return true;
}
}
return false;
}
static
struct rpc_xprt *xprt_switch_find_next_entry(struct list_head *head,
const struct rpc_xprt *cur)
{
struct rpc_xprt *pos, *prev = NULL;
list_for_each_entry_rcu(pos, head, xprt_switch) {
if (cur == prev)
return pos;
prev = pos;
}
return NULL;
}
static
struct rpc_xprt *xprt_switch_set_next_cursor(struct list_head *head,
struct rpc_xprt **cursor,
xprt_switch_find_xprt_t find_next)
{
struct rpc_xprt *cur, *pos, *old;
cur = READ_ONCE(*cursor);
for (;;) {
old = cur;
pos = find_next(head, old);
if (pos == NULL)
break;
cur = cmpxchg_relaxed(cursor, old, pos);
if (cur == old)
break;
}
return pos;
}
static
struct rpc_xprt *xprt_iter_next_entry_multiple(struct rpc_xprt_iter *xpi,
xprt_switch_find_xprt_t find_next)
{
struct rpc_xprt_switch *xps = rcu_dereference(xpi->xpi_xpswitch);
if (xps == NULL)
return NULL;
return xprt_switch_set_next_cursor(&xps->xps_xprt_list,
&xpi->xpi_cursor,
find_next);
}
static
struct rpc_xprt *xprt_switch_find_next_entry_roundrobin(struct list_head *head,
const struct rpc_xprt *cur)
{
struct rpc_xprt *ret;
ret = xprt_switch_find_next_entry(head, cur);
if (ret != NULL)
return ret;
return xprt_switch_find_first_entry(head);
}
static
struct rpc_xprt *xprt_iter_next_entry_roundrobin(struct rpc_xprt_iter *xpi)
{
return xprt_iter_next_entry_multiple(xpi,
xprt_switch_find_next_entry_roundrobin);
}
static
struct rpc_xprt *xprt_iter_next_entry_all(struct rpc_xprt_iter *xpi)
{
return xprt_iter_next_entry_multiple(xpi, xprt_switch_find_next_entry);
}
/*
* xprt_iter_rewind - Resets the xprt iterator
* @xpi: pointer to rpc_xprt_iter
*
* Resets xpi to ensure that it points to the first entry in the list
* of transports.
*/
static
void xprt_iter_rewind(struct rpc_xprt_iter *xpi)
{
rcu_read_lock();
xprt_iter_ops(xpi)->xpi_rewind(xpi);
rcu_read_unlock();
}
static void __xprt_iter_init(struct rpc_xprt_iter *xpi,
struct rpc_xprt_switch *xps,
const struct rpc_xprt_iter_ops *ops)
{
rcu_assign_pointer(xpi->xpi_xpswitch, xprt_switch_get(xps));
xpi->xpi_cursor = NULL;
xpi->xpi_ops = ops;
}
/**
* xprt_iter_init - Initialise an xprt iterator
* @xpi: pointer to rpc_xprt_iter
* @xps: pointer to rpc_xprt_switch
*
* Initialises the iterator to use the default iterator ops
* as set in xps. This function is mainly intended for internal
* use in the rpc_client.
*/
void xprt_iter_init(struct rpc_xprt_iter *xpi,
struct rpc_xprt_switch *xps)
{
__xprt_iter_init(xpi, xps, NULL);
}
/**
* xprt_iter_init_listall - Initialise an xprt iterator
* @xpi: pointer to rpc_xprt_iter
* @xps: pointer to rpc_xprt_switch
*
* Initialises the iterator to iterate once through the entire list
* of entries in xps.
*/
void xprt_iter_init_listall(struct rpc_xprt_iter *xpi,
struct rpc_xprt_switch *xps)
{
__xprt_iter_init(xpi, xps, &rpc_xprt_iter_listall);
}
/**
* xprt_iter_xchg_switch - Atomically swap out the rpc_xprt_switch
* @xpi: pointer to rpc_xprt_iter
* @xps: pointer to a new rpc_xprt_switch or NULL
*
* Swaps out the existing xpi->xpi_xpswitch with a new value.
*/
struct rpc_xprt_switch *xprt_iter_xchg_switch(struct rpc_xprt_iter *xpi,
struct rpc_xprt_switch *newswitch)
{
struct rpc_xprt_switch __rcu *oldswitch;
/* Atomically swap out the old xpswitch */
oldswitch = xchg(&xpi->xpi_xpswitch, RCU_INITIALIZER(newswitch));
if (newswitch != NULL)
xprt_iter_rewind(xpi);
return rcu_dereference_protected(oldswitch, true);
}
/**
* xprt_iter_destroy - Destroys the xprt iterator
* @xpi pointer to rpc_xprt_iter
*/
void xprt_iter_destroy(struct rpc_xprt_iter *xpi)
{
xprt_switch_put(xprt_iter_xchg_switch(xpi, NULL));
}
/**
* xprt_iter_xprt - Returns the rpc_xprt pointed to by the cursor
* @xpi: pointer to rpc_xprt_iter
*
* Returns a pointer to the struct rpc_xprt that is currently
* pointed to by the cursor.
* Caller must be holding rcu_read_lock().
*/
struct rpc_xprt *xprt_iter_xprt(struct rpc_xprt_iter *xpi)
{
WARN_ON_ONCE(!rcu_read_lock_held());
return xprt_iter_ops(xpi)->xpi_xprt(xpi);
}
static
struct rpc_xprt *xprt_iter_get_helper(struct rpc_xprt_iter *xpi,
struct rpc_xprt *(*fn)(struct rpc_xprt_iter *))
{
struct rpc_xprt *ret;
do {
ret = fn(xpi);
if (ret == NULL)
break;
ret = xprt_get(ret);
} while (ret == NULL);
return ret;
}
/**
* xprt_iter_get_xprt - Returns the rpc_xprt pointed to by the cursor
* @xpi: pointer to rpc_xprt_iter
*
* Returns a reference to the struct rpc_xprt that is currently
* pointed to by the cursor.
*/
struct rpc_xprt *xprt_iter_get_xprt(struct rpc_xprt_iter *xpi)
{
struct rpc_xprt *xprt;
rcu_read_lock();
xprt = xprt_iter_get_helper(xpi, xprt_iter_ops(xpi)->xpi_xprt);
rcu_read_unlock();
return xprt;
}
/**
* xprt_iter_get_next - Returns the next rpc_xprt following the cursor
* @xpi: pointer to rpc_xprt_iter
*
* Returns a reference to the struct rpc_xprt that immediately follows the
* entry pointed to by the cursor.
*/
struct rpc_xprt *xprt_iter_get_next(struct rpc_xprt_iter *xpi)
{
struct rpc_xprt *xprt;
rcu_read_lock();
xprt = xprt_iter_get_helper(xpi, xprt_iter_ops(xpi)->xpi_next);
rcu_read_unlock();
return xprt;
}
/* Policy for always returning the first entry in the rpc_xprt_switch */
static
const struct rpc_xprt_iter_ops rpc_xprt_iter_singular = {
.xpi_rewind = xprt_iter_no_rewind,
.xpi_xprt = xprt_iter_first_entry,
.xpi_next = xprt_iter_first_entry,
};
/* Policy for round-robin iteration of entries in the rpc_xprt_switch */
static
const struct rpc_xprt_iter_ops rpc_xprt_iter_roundrobin = {
.xpi_rewind = xprt_iter_default_rewind,
.xpi_xprt = xprt_iter_current_entry,
.xpi_next = xprt_iter_next_entry_roundrobin,
};
/* Policy for once-through iteration of entries in the rpc_xprt_switch */
static
const struct rpc_xprt_iter_ops rpc_xprt_iter_listall = {
.xpi_rewind = xprt_iter_default_rewind,
.xpi_xprt = xprt_iter_current_entry,
.xpi_next = xprt_iter_next_entry_all,
};