diff options
Diffstat (limited to 'compat/backport-4.7.c')
| -rw-r--r-- | compat/backport-4.7.c | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/compat/backport-4.7.c b/compat/backport-4.7.c new file mode 100644 index 0000000..b064707 --- /dev/null +++ b/compat/backport-4.7.c @@ -0,0 +1,182 @@ +/* + * Copyright(c) 2016 Hauke Mehrtens <hauke@hauke-m.de> + * + * Backport functionality introduced in Linux 4.7. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/export.h> +#include <linux/list.h> +#include <linux/rcupdate.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/skbuff.h> +#include <net/netlink.h> + +/** + * __nla_reserve_64bit - reserve room for attribute on the skb and align it + * @skb: socket buffer to reserve room on + * @attrtype: attribute type + * @attrlen: length of attribute payload + * + * Adds a netlink attribute header to a socket buffer and reserves + * room for the payload but does not copy it. It also ensure that this + * attribute will be 64-bit aign. + * + * The caller is responsible to ensure that the skb provides enough + * tailroom for the attribute header and payload. + */ +struct nlattr *__nla_reserve_64bit(struct sk_buff *skb, int attrtype, + int attrlen, int padattr) +{ + if (nla_need_padding_for_64bit(skb)) + nla_align_64bit(skb, padattr); + + return __nla_reserve(skb, attrtype, attrlen); +} +EXPORT_SYMBOL_GPL(__nla_reserve_64bit); + +/** + * nla_reserve_64bit - reserve room for attribute on the skb and align it + * @skb: socket buffer to reserve room on + * @attrtype: attribute type + * @attrlen: length of attribute payload + * + * Adds a netlink attribute header to a socket buffer and reserves + * room for the payload but does not copy it. It also ensure that this + * attribute will be 64-bit aign. + * + * Returns NULL if the tailroom of the skb is insufficient to store + * the attribute header and payload. + */ +struct nlattr *nla_reserve_64bit(struct sk_buff *skb, int attrtype, int attrlen, + int padattr) +{ + size_t len; + + if (nla_need_padding_for_64bit(skb)) + len = nla_total_size_64bit(attrlen); + else + len = nla_total_size(attrlen); + if (unlikely(skb_tailroom(skb) < len)) + return NULL; + + return __nla_reserve_64bit(skb, attrtype, attrlen, padattr); +} +EXPORT_SYMBOL_GPL(nla_reserve_64bit); + +/** + * __nla_put_64bit - Add a netlink attribute to a socket buffer and align it + * @skb: socket buffer to add attribute to + * @attrtype: attribute type + * @attrlen: length of attribute payload + * @data: head of attribute payload + * + * The caller is responsible to ensure that the skb provides enough + * tailroom for the attribute header and payload. + */ +void __nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen, + const void *data, int padattr) +{ + struct nlattr *nla; + + nla = __nla_reserve_64bit(skb, attrtype, attrlen, padattr); + memcpy(nla_data(nla), data, attrlen); +} +EXPORT_SYMBOL_GPL(__nla_put_64bit); + +/** + * nla_put_64bit - Add a netlink attribute to a socket buffer and align it + * @skb: socket buffer to add attribute to + * @attrtype: attribute type + * @attrtype: attribute type + * @attrlen: length of attribute payload + * @data: head of attribute payload + * + * Returns -EMSGSIZE if the tailroom of the skb is insufficient to store + * the attribute header and payload. + */ +int nla_put_64bit(struct sk_buff *skb, int attrtype, int attrlen, + const void *data, int padattr) +{ + size_t len; + + if (nla_need_padding_for_64bit(skb)) + len = nla_total_size_64bit(attrlen); + else + len = nla_total_size(attrlen); + if (unlikely(skb_tailroom(skb) < len)) + return -EMSGSIZE; + + __nla_put_64bit(skb, attrtype, attrlen, data, padattr); + return 0; +} +EXPORT_SYMBOL_GPL(nla_put_64bit); + +/* + * Below 3.18 or if the kernel has devcoredump disabled, we copied the + * entire devcoredump, so no need to define these functions. + */ +#if LINUX_VERSION_IS_GEQ(3,18,0) && \ + !defined(CPTCFG_BPAUTO_BUILD_WANT_DEV_COREDUMP) +#include <linux/devcoredump.h> +#include <linux/scatterlist.h> + +static void devcd_free_sgtable(void *data) +{ + struct scatterlist *table = data; + 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); +} + +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); +} + +void dev_coredumpsg(struct device *dev, struct scatterlist *table, + size_t datalen, gfp_t gfp) +{ + dev_coredumpm(dev, THIS_MODULE, table, datalen, gfp, + devcd_read_from_sgtable, devcd_free_sgtable); +} +EXPORT_SYMBOL_GPL(dev_coredumpsg); +#endif /* >= 3.18.0 */ |