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Date: Mon, 28 Sep 2015 11:59:31 +0300
From: Dan Carpenter <dan.carpenter@...cle.com>
To: Chandra S Gorentla <csgorentla@...il.com>
Cc: gregkh@...uxfoundation.org, rachel.kim@...el.com,
dean.lee@...el.com, chris.park@...el.com,
devel@...verdev.osuosl.org, linux-wireless@...r.kernel.org,
johnny.kim@...el.com, linux-kernel@...r.kernel.org,
sudipm.mukherjee@...il.com
Subject: Re: [PATCH] drivers: staging: wilc1000: Replace message queue with
standard Linux lists
On Sun, Sep 27, 2015 at 07:43:18PM +0530, Chandra S Gorentla wrote:
> The message queue is replaced with standard Linux linked list. A check for
> return value of receive method is added.
>
> Signed-off-by: Chandra S Gorentla <csgorentla@...il.com>
> ---
> drivers/staging/wilc1000/host_interface.c | 7 +++-
> drivers/staging/wilc1000/wilc_msgqueue.c | 62 ++++++++++++++-----------------
> drivers/staging/wilc1000/wilc_platform.h | 5 ++-
> 3 files changed, 36 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/staging/wilc1000/host_interface.c b/drivers/staging/wilc1000/host_interface.c
> index 62f4a8a..8d0776f 100644
> --- a/drivers/staging/wilc1000/host_interface.c
> +++ b/drivers/staging/wilc1000/host_interface.c
> @@ -4304,11 +4304,16 @@ static int hostIFthread(void *pvArg)
> u32 u32Ret;
> struct host_if_msg msg;
> tstrWILC_WFIDrv *pstrWFIDrv;
> + int recv_ret;
Name it "ret".
int ret;
>
> memset(&msg, 0, sizeof(struct host_if_msg));
>
> while (1) {
> - wilc_mq_recv(&gMsgQHostIF, &msg, sizeof(struct host_if_msg), &u32Ret);
> + recv_ret = wilc_mq_recv(&gMsgQHostIF, &msg,
> + sizeof(struct host_if_msg), &u32Ret);
> + if (recv_ret)
> + continue;
This looks like a forever loop.
> +
> pstrWFIDrv = (tstrWILC_WFIDrv *)msg.drvHandler;
> if (msg.id == HOST_IF_MSG_EXIT) {
> PRINT_D(GENERIC_DBG, "THREAD: Exiting HostIfThread\n");
> diff --git a/drivers/staging/wilc1000/wilc_msgqueue.c b/drivers/staging/wilc1000/wilc_msgqueue.c
> index 869736a..67617d5 100644
> --- a/drivers/staging/wilc1000/wilc_msgqueue.c
> +++ b/drivers/staging/wilc1000/wilc_msgqueue.c
> @@ -12,9 +12,15 @@
> */
> int wilc_mq_create(WILC_MsgQueueHandle *pHandle)
> {
> + pHandle->msg_cache = kmem_cache_create("wilc_message_queue",
> + sizeof(Message),
> + 0, SLAB_POISON, NULL);
> + if (!pHandle->msg_cache)
> + return -ENOMEM;
This is a separate thing from using list macros. Or maybe it's not but
that isn't explained in the changelog. Do one thing per patch so it's
easier to review.
> +
> spin_lock_init(&pHandle->strCriticalSection);
> sema_init(&pHandle->hSem, 0);
> - pHandle->pstrMessageList = NULL;
> + INIT_LIST_HEAD(&pHandle->msg_list_head);
> pHandle->u32ReceiversCount = 0;
> pHandle->bExiting = false;
> return 0;
> @@ -28,6 +34,7 @@ int wilc_mq_create(WILC_MsgQueueHandle *pHandle)
> */
> int wilc_mq_destroy(WILC_MsgQueueHandle *pHandle)
> {
> + Message *msg;
> pHandle->bExiting = true;
>
> /* Release any waiting receiver thread. */
> @@ -36,13 +43,16 @@ int wilc_mq_destroy(WILC_MsgQueueHandle *pHandle)
> pHandle->u32ReceiversCount--;
> }
>
> - while (pHandle->pstrMessageList) {
> - Message *pstrMessge = pHandle->pstrMessageList->pstrNext;
> -
> - kfree(pHandle->pstrMessageList);
> - pHandle->pstrMessageList = pstrMessge;
> + while (!list_empty(&pHandle->msg_list_head)) {
> + msg = list_first_entry(&pHandle->msg_list_head,
> + Message, link);
> + list_del(&msg->link);
> + kfree(msg->pvBuffer);
> + kmem_cache_free(pHandle->msg_cache, msg);
> }
>
> + kmem_cache_destroy(pHandle->msg_cache);
> +
> return 0;
> }
>
> @@ -74,41 +84,28 @@ int wilc_mq_send(WILC_MsgQueueHandle *pHandle,
> spin_lock_irqsave(&pHandle->strCriticalSection, flags);
>
> /* construct a new message */
> - pstrMessage = kmalloc(sizeof(Message), GFP_ATOMIC);
> - if (!pstrMessage)
> + pstrMessage = kmem_cache_zalloc(pHandle->msg_cache, GFP_ATOMIC);
> + if (!pstrMessage) {
> + spin_unlock_irqrestore(&pHandle->strCriticalSection, flags);
> return -ENOMEM;
> + }
Do the allocation outside the lock so it doesn't have to be atomic.
> pstrMessage->u32Length = u32SendBufferSize;
> - pstrMessage->pstrNext = NULL;
> pstrMessage->pvBuffer = kmalloc(u32SendBufferSize, GFP_ATOMIC);
> if (!pstrMessage->pvBuffer) {
> + kmem_cache_free(pHandle->msg_cache, pstrMessage);
> result = -ENOMEM;
> goto ERRORHANDLER;
This goto is meaningless now that it doesn't handle any errors. Just do
a direct return. Except, wait, aren't we holding a couple locks? This
looks buggy.
> }
> memcpy(pstrMessage->pvBuffer, pvSendBuffer, u32SendBufferSize);
>
> /* add it to the message queue */
> - if (!pHandle->pstrMessageList) {
> - pHandle->pstrMessageList = pstrMessage;
> - } else {
> - Message *pstrTailMsg = pHandle->pstrMessageList;
> -
> - while (pstrTailMsg->pstrNext)
> - pstrTailMsg = pstrTailMsg->pstrNext;
> -
> - pstrTailMsg->pstrNext = pstrMessage;
> - }
> + list_add_tail(&pstrMessage->link, &pHandle->msg_list_head);
>
> spin_unlock_irqrestore(&pHandle->strCriticalSection, flags);
>
> up(&pHandle->hSem);
>
> ERRORHANDLER:
> - /* error occured, free any allocations */
> - if (pstrMessage) {
> - kfree(pstrMessage->pvBuffer);
> - kfree(pstrMessage);
> - }
> -
> return result;
> }
>
> @@ -144,11 +141,6 @@ int wilc_mq_recv(WILC_MsgQueueHandle *pHandle,
> down(&pHandle->hSem);
>
> /* other non-timeout scenarios */
> - if (result) {
> - PRINT_ER("Non-timeout\n");
> - return result;
> - }
> -
This is correct, but not related to list macros. Do it in a separate
patch.
> if (pHandle->bExiting) {
> PRINT_ER("pHandle fail\n");
> return -EFAULT;
> @@ -156,12 +148,13 @@ int wilc_mq_recv(WILC_MsgQueueHandle *pHandle,
>
> spin_lock_irqsave(&pHandle->strCriticalSection, flags);
>
> - pstrMessage = pHandle->pstrMessageList;
> - if (!pstrMessage) {
> + if (list_empty(&pHandle->msg_list_head)) {
> spin_unlock_irqrestore(&pHandle->strCriticalSection, flags);
> PRINT_ER("pstrMessage is null\n");
This printk is outdated now.
> return -EFAULT;
> }
> +
regards,
dan carpenter
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