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Revision 16b34aa44b257155d9392a19e08e4ce139bc2789 authored by Ronnie Sahlberg on 08 March 2019, 02:58:21 UTC, committed by Steve French on 15 March 2019, 00:32:35 UTC 
cifs: prevent starvation in wait_for_free_credits for multi-credit requests
 
Reserve the last MAX_COMPOUND credits for any request asking for >1 credit.
This is to prevent future compound requests from becoming starved while waiting
for potentially many requests is there is a large number of concurrent
singe-credit requests.

However, we need to protect from servers that are very slow to hand out
new credits on new sessions so we only do this IFF there are 2*MAX_COMPOUND
(arbitrary) credits already in flight.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
1 parent b227d21
Raw File
ashldi3.c 
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see the file COPYING, or write
 * to the Free Software Foundation, Inc.
 */

#include <linux/export.h>

#include <linux/libgcc.h>

long long notrace __ashldi3(long long u, word_type b)
{
	DWunion uu, w;
	word_type bm;

	if (b == 0)
		return u;

	uu.ll = u;
	bm = 32 - b;

	if (bm <= 0) {
		w.s.low = 0;
		w.s.high = (unsigned int) uu.s.low << -bm;
	} else {
		const unsigned int carries = (unsigned int) uu.s.low >> bm;

		w.s.low = (unsigned int) uu.s.low << b;
		w.s.high = ((unsigned int) uu.s.high << b) | carries;
	}

	return w.ll;
}
EXPORT_SYMBOL(__ashldi3);
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