[PATCH] devcoredump: add scatterlist support
From: Johannes Berg
Date: Fri Dec 11 2015 - 05:56:10 EST
From: Aviya Erenfeld <aviya.erenfeld@xxxxxxxxx>
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@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
drivers/base/devcoredump.c | 83 +++++++++++++++++++++++++---
drivers/net/wireless/iwlwifi/mvm/mac80211.c | 4 +-
include/linux/devcoredump.h | 86 ++++++++++++++++++++++++++---
3 files changed, 154 insertions(+), 19 deletions(-)
diff --git a/drivers/base/devcoredump.c b/drivers/base/devcoredump.c
index 1bd120a0b084..240374fd1838 100644
--- a/drivers/base/devcoredump.c
+++ b/drivers/base/devcoredump.c
@@ -4,6 +4,7 @@
* GPL LICENSE SUMMARY
*
* Copyright(c) 2014 Intel Mobile Communications GmbH
+ * 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
@@ -41,12 +42,12 @@ static bool devcd_disabled;
struct devcd_entry {
struct device devcd_dev;
- const void *data;
+ void *data;
size_t datalen;
struct module *owner;
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);
struct delayed_work del_wk;
struct device *failing_dev;
};
@@ -174,7 +175,7 @@ static struct class devcd_class = {
};
static ssize_t devcd_readv(char *buffer, loff_t offset, size_t count,
- const void *data, size_t datalen)
+ void *data, size_t datalen)
{
if (offset > datalen)
return -EINVAL;
@@ -188,6 +189,11 @@ static ssize_t devcd_readv(char *buffer, loff_t offset, size_t count,
return count;
}
+static void devcd_freev(void *data)
+{
+ vfree(data);
+}
+
/**
* dev_coredumpv - create device coredump with vmalloc data
* @dev: the struct device for the crashed device
@@ -198,10 +204,10 @@ static ssize_t devcd_readv(char *buffer, loff_t offset, size_t count,
* This function takes ownership of the vmalloc'ed data and will free
* it when it is no longer used. See dev_coredumpm() for more information.
*/
-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)
{
- dev_coredumpm(dev, NULL, data, datalen, gfp, devcd_readv, vfree);
+ dev_coredumpm(dev, NULL, data, datalen, gfp, devcd_readv, devcd_freev);
}
EXPORT_SYMBOL_GPL(dev_coredumpv);
@@ -213,6 +219,44 @@ static int devcd_match_failing(struct device *dev, const void *failing)
}
/**
+ * devcd_free_sgtable - free all the memory of the given scatterlist table
+ * (i.e. both pages and scatterlist instances)
+ * NOTE: if two tables allocated with devcd_alloc_sgtable and then chained
+ * using the sg_chain function then that function should be called only once
+ * on the chained table
+ * @table: pointer to sg_table to free
+ */
+static void devcd_free_sgtable(void *data)
+{
+ _devcd_free_sgtable(data);
+}
+
+/**
+ * devcd_read_from_table - copy data from sg_table to a given buffer
+ * and return the number of bytes read
+ * @buffer: the buffer to copy the data to it
+ * @buf_len: the length of the buffer
+ * @data: the scatterlist table to copy from
+ * @offset: start copy from @offset@ bytes from the head of the data
+ * in the given scatterlist
+ * @data_len: the length of the data in the sg_table
+ */
+static ssize_t devcd_read_from_sgtable(char *buffer, loff_t offset,
+ size_t buf_len, void *data,
+ size_t data_len)
+{
+ struct scatterlist *table = data;
+
+ if (offset > data_len)
+ return -EINVAL;
+
+ if (offset + buf_len > data_len)
+ buf_len = data_len - offset;
+ return sg_pcopy_to_buffer(table, sg_nents(table), buffer, buf_len,
+ offset);
+}
+
+/**
* dev_coredumpm - create device coredump with read/free methods
* @dev: the struct device for the crashed device
* @owner: the module that contains the read/free functions, use %THIS_MODULE
@@ -228,10 +272,10 @@ static int devcd_match_failing(struct device *dev, const void *failing)
* function will be called to free the data.
*/
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))
{
static atomic_t devcd_count = ATOMIC_INIT(0);
struct devcd_entry *devcd;
@@ -291,6 +335,27 @@ void dev_coredumpm(struct device *dev, struct module *owner,
}
EXPORT_SYMBOL_GPL(dev_coredumpm);
+/**
+ * dev_coredumpmsg - create device coredump that uses scatterlist as data
+ * parameter
+ * @dev: the struct device for the crashed device
+ * @table: the dump data
+ * @datalen: length of the data
+ * @gfp: allocation flags
+ *
+ * Creates a new device coredump for the given device. If a previous one hasn't
+ * been read yet, the new coredump is discarded. The data lifetime is determined
+ * by the device coredump framework and when it is no longer needed
+ * it will free the data.
+ */
+void dev_coredumpsg(struct device *dev, struct scatterlist *table,
+ size_t datalen, gfp_t gfp)
+{
+ dev_coredumpm(dev, NULL, table, datalen, gfp, devcd_read_from_sgtable,
+ devcd_free_sgtable);
+}
+EXPORT_SYMBOL_GPL(dev_coredumpsg);
+
static int __init devcoredump_init(void)
{
return class_register(&devcd_class);
diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
index e88afac51c5d..b0f83e20e1c2 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
@@ -940,7 +940,7 @@ static void iwl_mvm_cleanup_iterator(void *data, u8 *mac,
}
static ssize_t iwl_mvm_read_coredump(char *buffer, loff_t offset, size_t count,
- const void *data, size_t datalen)
+ void *data, size_t datalen)
{
const struct iwl_mvm_dump_ptrs *dump_ptrs = data;
ssize_t bytes_read;
@@ -973,7 +973,7 @@ static ssize_t iwl_mvm_read_coredump(char *buffer, loff_t offset, size_t count,
return bytes_read + bytes_read_trans;
}
-static void iwl_mvm_free_coredump(const void *data)
+static void iwl_mvm_free_coredump(void *data)
{
const struct iwl_mvm_dump_ptrs *fw_error_dump = data;
diff --git a/include/linux/devcoredump.h b/include/linux/devcoredump.h
index c0a360e99f64..269521f143ac 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_coredumpv(struct device *dev, const void *data,
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 */
--
2.6.2
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