devcoredump: add scatterlist support
Add scatterlist support (dev_coredumpsg) to allow drivers to avoid
vmalloc() like dev_coredumpm(), while also avoiding the module
reference that the latter function requires.
This internally uses dev_coredumpm() with function inside the
devcoredump module, requiring removing the const
(which touches the driver using it.)
Signed-off-by: Aviya Erenfeld <aviya.erenfeld@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/devcoredump.h b/include/linux/devcoredump.h
index c0a360e..269521f 100644
--- a/include/linux/devcoredump.h
+++ b/include/linux/devcoredump.h
@@ -1,3 +1,22 @@
+/*
+ * This file is provided under the GPLv2 license.
+ *
+ * GPL LICENSE SUMMARY
+ *
+ * Copyright(c) 2015 Intel Deutschland GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * The full GNU General Public License is included in this distribution
+ * in the file called COPYING.
+ */
#ifndef __DEVCOREDUMP_H
#define __DEVCOREDUMP_H
@@ -5,17 +24,62 @@
#include <linux/module.h>
#include <linux/vmalloc.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+
+/*
+ * _devcd_free_sgtable - free all the memory of the given scatterlist table
+ * (i.e. both pages and scatterlist instances)
+ * NOTE: if two tables allocated and chained using the sg_chain function then
+ * this function should be called only once on the first table
+ * @table: pointer to sg_table to free
+ */
+static inline void _devcd_free_sgtable(struct scatterlist *table)
+{
+ int i;
+ struct page *page;
+ struct scatterlist *iter;
+ struct scatterlist *delete_iter;
+
+ /* free pages */
+ iter = table;
+ for_each_sg(table, iter, sg_nents(table), i) {
+ page = sg_page(iter);
+ if (page)
+ __free_page(page);
+ }
+
+ /* then free all chained tables */
+ iter = table;
+ delete_iter = table; /* always points on a head of a table */
+ while (!sg_is_last(iter)) {
+ iter++;
+ if (sg_is_chain(iter)) {
+ iter = sg_chain_ptr(iter);
+ kfree(delete_iter);
+ delete_iter = iter;
+ }
+ }
+
+ /* free the last table */
+ kfree(delete_iter);
+}
+
+
#ifdef CONFIG_DEV_COREDUMP
-void dev_coredumpv(struct device *dev, const void *data, size_t datalen,
+void dev_coredumpv(struct device *dev, void *data, size_t datalen,
gfp_t gfp);
void dev_coredumpm(struct device *dev, struct module *owner,
- const void *data, size_t datalen, gfp_t gfp,
+ void *data, size_t datalen, gfp_t gfp,
ssize_t (*read)(char *buffer, loff_t offset, size_t count,
- const void *data, size_t datalen),
- void (*free)(const void *data));
+ void *data, size_t datalen),
+ void (*free)(void *data));
+
+void dev_coredumpsg(struct device *dev, struct scatterlist *table,
+ size_t datalen, gfp_t gfp);
#else
-static inline void dev_coredumpv(struct device *dev, const void *data,
+static inline void dev_coredumpv(struct device *dev, void *data,
size_t datalen, gfp_t gfp)
{
vfree(data);
@@ -23,13 +87,19 @@
static inline void
dev_coredumpm(struct device *dev, struct module *owner,
- const void *data, size_t datalen, gfp_t gfp,
+ void *data, size_t datalen, gfp_t gfp,
ssize_t (*read)(char *buffer, loff_t offset, size_t count,
- const void *data, size_t datalen),
- void (*free)(const void *data))
+ void *data, size_t datalen),
+ void (*free)(void *data))
{
free(data);
}
+
+static inline void dev_coredumpsg(struct device *dev, struct scatterlist *table,
+ size_t datalen, gfp_t gfp)
+{
+ _devcd_free_sgtable(table);
+}
#endif /* CONFIG_DEV_COREDUMP */
#endif /* __DEVCOREDUMP_H */