/*
 * T10 Data Integrity Field CRC16 calculation
 *
 * Copyright (c) 2007 Oracle Corporation.  All rights reserved.
 * Written by Martin K. Petersen <martin.petersen@oracle.com>
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2. See the file COPYING for more details.
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/crc-t10dif.h>
#include <linux/err.h>
#include <linux/init.h>
#include <crypto/hash.h>
#include <linux/static_key.h>

static struct crypto_shash *crct10dif_tfm;
static struct static_key crct10dif_fallback __read_mostly;

__u16 crc_t10dif_update(__u16 crc, const unsigned char *buffer, size_t len)
{
	struct {
		struct shash_desc shash;
		char ctx[2];
	} desc;
	int err;

	if (static_key_false(&crct10dif_fallback))
		return crc_t10dif_generic(crc, buffer, len);

	desc.shash.tfm = crct10dif_tfm;
	desc.shash.flags = 0;
	*(__u16 *)desc.ctx = crc;

	err = crypto_shash_update(&desc.shash, buffer, len);
	BUG_ON(err);

	return *(__u16 *)desc.ctx;
}
EXPORT_SYMBOL(crc_t10dif_update);

__u16 crc_t10dif(const unsigned char *buffer, size_t len)
{
	return crc_t10dif_update(0, buffer, len);
}
EXPORT_SYMBOL(crc_t10dif);

static int __init crc_t10dif_mod_init(void)
{
	crct10dif_tfm = crypto_alloc_shash("crct10dif", 0, 0);
	if (IS_ERR(crct10dif_tfm)) {
		static_key_slow_inc(&crct10dif_fallback);
		crct10dif_tfm = NULL;
	}
	return 0;
}

static void __exit crc_t10dif_mod_fini(void)
{
	crypto_free_shash(crct10dif_tfm);
}

module_init(crc_t10dif_mod_init);
module_exit(crc_t10dif_mod_fini);

MODULE_DESCRIPTION("T10 DIF CRC calculation");
MODULE_LICENSE("GPL");
MODULE_SOFTDEP("pre: crct10dif");
7cbd59fb873b7ba20d60d1ddf3c'>refs</a><a href='/cgit.cgi/linux/net-next.git/log/drivers/usb/host/xhci-trace.c'>log</a><a href='/cgit.cgi/linux/net-next.git/tree/drivers/usb/host/xhci-trace.c?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>tree</a><a class='active' href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/host/xhci-trace.c?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>commit</a><a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/host/xhci-trace.c?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>diff</a></td><td class='form'><form class='right' method='get' action='/cgit.cgi/linux/net-next.git/log/drivers/usb/host/xhci-trace.c'>
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>drivers</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>usb</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/host?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>host</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/host/xhci-trace.c?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>xhci-trace.c</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Dan Williams &lt;dan.j.williams@intel.com&gt;</td><td class='right'>2016-12-06 17:03:35 -0800</td></tr>
<tr><th>committer</th><td>Dan Williams &lt;dan.j.williams@intel.com&gt;</td><td class='right'>2016-12-06 17:42:37 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/host/xhci-trace.c?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c</a> (<a href='/cgit.cgi/linux/net-next.git/patch/drivers/usb/host/xhci-trace.c?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>d71d337b3a5b9858907c6a4a0797ced074302590</a> /<a href='/cgit.cgi/linux/net-next.git/tree/drivers/usb/host/xhci-trace.c?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>drivers/usb/host/xhci-trace.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/host/xhci-trace.c?id=a7de92dac9f0dbf01deb56fe1d661d7baac097e1'>a7de92dac9f0dbf01deb56fe1d661d7baac097e1</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/host/xhci-trace.c?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c&amp;id2=a7de92dac9f0dbf01deb56fe1d661d7baac097e1'>diff</a>)</td></tr></table>
<div class='commit-subject'>device-dax: fix private mapping restriction, permit read-only</div><div class='commit-msg'>Hugh notes in response to commit 4cb19355ea19 "device-dax: fail all
private mapping attempts":

  "I think that is more restrictive than you intended: haven't tried, but I
  believe it rejects a PROT_READ, MAP_SHARED, O_RDONLY fd mmap, leaving no
  way to mmap /dev/dax without write permission to it."

Indeed it does restrict read-only mappings, switch to checking
VM_MAYSHARE, not VM_SHARED.

Cc: &lt;stable@vger.kernel.org&gt;
Cc: Dave Hansen &lt;dave.hansen@linux.intel.com&gt;
Cc: Pawel Lebioda &lt;pawel.lebioda@intel.com&gt;
Fixes: 4cb19355ea19 ("device-dax: fail all private mapping attempts")
Reported-by: Hugh Dickins &lt;hughd@google.com&gt;
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=325896ffdf90f7cbd59fb873b7ba20d60d1ddf3c'>Diffstat</a> (limited to 'drivers/usb/host/xhci-trace.c')</div><table summary='diffstat' class='diffstat'>