Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read()

Commit a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")
added the proper mb(), but removed the test "prev_write_sz < pending_sz"
when making the signal decision.

As a result, the guest can signal the host unnecessarily,
and then the host can throttle the guest because the host
thinks the guest is buggy or malicious; finally the user
running stress test can perceive intermittent freeze of
the guest.

This patch brings back the test, and properly handles the
in-place consumption APIs used by NetVSC (see get_next_pkt_raw(),
put_pkt_raw() and commit_rd_index()).

Fixes: a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in
hv_need_to_signal_on_read()")

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Reported-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
Tested-by: Rolf Neugebauer <rolf.neugebauer@docker.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

path: root/include/crypto/cast6.h

#ifndef _CRYPTO_CAST6_H
#define _CRYPTO_CAST6_H

#include <linux/types.h>
#include <linux/crypto.h>
#include <crypto/cast_common.h>

#define CAST6_BLOCK_SIZE 16
#define CAST6_MIN_KEY_SIZE 16
#define CAST6_MAX_KEY_SIZE 32

struct cast6_ctx {
	u32 Km[12][4];
	u8 Kr[12][4];
};

int __cast6_setkey(struct cast6_ctx *ctx, const u8 *key,
		   unsigned int keylen, u32 *flags);
int cast6_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen);

void __cast6_encrypt(struct cast6_ctx *ctx, u8 *dst, const u8 *src);
void __cast6_decrypt(struct cast6_ctx *ctx, u8 *dst, const u8 *src);

#endif