From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- drivers/scsi/arm/msgqueue.c | 168 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 168 insertions(+) create mode 100644 drivers/scsi/arm/msgqueue.c (limited to 'drivers/scsi/arm/msgqueue.c') diff --git a/drivers/scsi/arm/msgqueue.c b/drivers/scsi/arm/msgqueue.c new file mode 100644 index 000000000..581158313 --- /dev/null +++ b/drivers/scsi/arm/msgqueue.c @@ -0,0 +1,168 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/drivers/acorn/scsi/msgqueue.c + * + * Copyright (C) 1997-1998 Russell King + * + * message queue handling + */ +#include +#include +#include +#include + +#include "msgqueue.h" + +/* + * Function: struct msgqueue_entry *mqe_alloc(MsgQueue_t *msgq) + * Purpose : Allocate a message queue entry + * Params : msgq - message queue to claim entry for + * Returns : message queue entry or NULL. + */ +static struct msgqueue_entry *mqe_alloc(MsgQueue_t *msgq) +{ + struct msgqueue_entry *mq; + + if ((mq = msgq->free) != NULL) + msgq->free = mq->next; + + return mq; +} + +/* + * Function: void mqe_free(MsgQueue_t *msgq, struct msgqueue_entry *mq) + * Purpose : free a message queue entry + * Params : msgq - message queue to free entry from + * mq - message queue entry to free + */ +static void mqe_free(MsgQueue_t *msgq, struct msgqueue_entry *mq) +{ + if (mq) { + mq->next = msgq->free; + msgq->free = mq; + } +} + +/* + * Function: void msgqueue_initialise(MsgQueue_t *msgq) + * Purpose : initialise a message queue + * Params : msgq - queue to initialise + */ +void msgqueue_initialise(MsgQueue_t *msgq) +{ + int i; + + msgq->qe = NULL; + msgq->free = &msgq->entries[0]; + + for (i = 0; i < NR_MESSAGES; i++) + msgq->entries[i].next = &msgq->entries[i + 1]; + + msgq->entries[NR_MESSAGES - 1].next = NULL; +} + + +/* + * Function: void msgqueue_free(MsgQueue_t *msgq) + * Purpose : free a queue + * Params : msgq - queue to free + */ +void msgqueue_free(MsgQueue_t *msgq) +{ +} + +/* + * Function: int msgqueue_msglength(MsgQueue_t *msgq) + * Purpose : calculate the total length of all messages on the message queue + * Params : msgq - queue to examine + * Returns : number of bytes of messages in queue + */ +int msgqueue_msglength(MsgQueue_t *msgq) +{ + struct msgqueue_entry *mq = msgq->qe; + int length = 0; + + for (mq = msgq->qe; mq; mq = mq->next) + length += mq->msg.length; + + return length; +} + +/* + * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno) + * Purpose : return a message + * Params : msgq - queue to obtain message from + * : msgno - message number + * Returns : pointer to message string, or NULL + */ +struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno) +{ + struct msgqueue_entry *mq; + + for (mq = msgq->qe; mq && msgno; mq = mq->next, msgno--); + + return mq ? &mq->msg : NULL; +} + +/* + * Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...) + * Purpose : add a message onto a message queue + * Params : msgq - queue to add message on + * length - length of message + * ... - message bytes + * Returns : != 0 if successful + */ +int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...) +{ + struct msgqueue_entry *mq = mqe_alloc(msgq); + va_list ap; + + if (mq) { + struct msgqueue_entry **mqp; + int i; + + va_start(ap, length); + for (i = 0; i < length; i++) + mq->msg.msg[i] = va_arg(ap, unsigned int); + va_end(ap); + + mq->msg.length = length; + mq->msg.fifo = 0; + mq->next = NULL; + + mqp = &msgq->qe; + while (*mqp) + mqp = &(*mqp)->next; + + *mqp = mq; + } + + return mq != NULL; +} + +/* + * Function: void msgqueue_flush(MsgQueue_t *msgq) + * Purpose : flush all messages from message queue + * Params : msgq - queue to flush + */ +void msgqueue_flush(MsgQueue_t *msgq) +{ + struct msgqueue_entry *mq, *mqnext; + + for (mq = msgq->qe; mq; mq = mqnext) { + mqnext = mq->next; + mqe_free(msgq, mq); + } + msgq->qe = NULL; +} + +EXPORT_SYMBOL(msgqueue_initialise); +EXPORT_SYMBOL(msgqueue_free); +EXPORT_SYMBOL(msgqueue_msglength); +EXPORT_SYMBOL(msgqueue_getmsg); +EXPORT_SYMBOL(msgqueue_addmsg); +EXPORT_SYMBOL(msgqueue_flush); + +MODULE_AUTHOR("Russell King"); +MODULE_DESCRIPTION("SCSI message queue handling"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1