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Commit 9713d9e6 authored by Karsten Keil's avatar Karsten Keil Committed by Linus Torvalds
Browse files

i4l: fix random freezes with AVM B1 drivers 



This fix the same issue which was debbuged for the C4 controller for the B1
versions.

The capilib_ function modify or traverse a linked list without locking.

This patch extends the existing locking to the calls of these function to
prevent access to a list which is in the middle of a modification.

Signed-off-by: default avatarKarsten Keil <kkeil@suse.de>
C: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0c42ea3f

drivers/isdn/hardware/avm/b1.c

+13 −15
Original line number Diff line number Diff line
@@ -321,12 +321,15 @@ void b1_reset_ctr(struct capi_ctr *ctrl) 
	avmctrl_info *cinfo = (avmctrl_info *)(ctrl->driverdata);

	avmcard *card = cinfo->card;

	unsigned int port = card->port;

	unsigned long flags;



	b1_reset(port);

	b1_reset(port);



	memset(cinfo->version, 0, sizeof(cinfo->version));

	spin_lock_irqsave(&card->lock, flags);

	capilib_release(&cinfo->ncci_head);

	spin_unlock_irqrestore(&card->lock, flags);

	capi_ctr_reseted(ctrl);

}
@@ -361,9 +364,8 @@ void b1_release_appl(struct capi_ctr *ctrl, u16 appl) 
	unsigned int port = card->port;

	unsigned long flags;



	capilib_release_appl(&cinfo->ncci_head, appl);



	spin_lock_irqsave(&card->lock, flags);

	capilib_release_appl(&cinfo->ncci_head, appl);

	b1_put_byte(port, SEND_RELEASE);

	b1_put_word(port, appl);

	spin_unlock_irqrestore(&card->lock, flags);
@@ -380,27 +382,27 @@ u16 b1_send_message(struct capi_ctr *ctrl, struct sk_buff *skb) 
	u8 subcmd = CAPIMSG_SUBCOMMAND(skb->data);

	u16 dlen, retval;



	spin_lock_irqsave(&card->lock, flags);

	if (CAPICMD(cmd, subcmd) == CAPI_DATA_B3_REQ) {

		retval = capilib_data_b3_req(&cinfo->ncci_head,

					     CAPIMSG_APPID(skb->data),

					     CAPIMSG_NCCI(skb->data),

					     CAPIMSG_MSGID(skb->data));

		if (retval != CAPI_NOERROR) 

		if (retval != CAPI_NOERROR) {

			spin_unlock_irqrestore(&card->lock, flags);

			return retval;

		}



		dlen = CAPIMSG_DATALEN(skb->data);



	 	spin_lock_irqsave(&card->lock, flags);

		b1_put_byte(port, SEND_DATA_B3_REQ);

		b1_put_slice(port, skb->data, len);

		b1_put_slice(port, skb->data + len, dlen);

		spin_unlock_irqrestore(&card->lock, flags);

	} else {

	 	spin_lock_irqsave(&card->lock, flags);

		b1_put_byte(port, SEND_MESSAGE);

		b1_put_slice(port, skb->data, len);

		spin_unlock_irqrestore(&card->lock, flags);

	}

	spin_unlock_irqrestore(&card->lock, flags);



	dev_kfree_skb_any(skb);

	return CAPI_NOERROR;
@@ -534,17 +536,17 @@ irqreturn_t b1_interrupt(int interrupt, void *devptr) 


		ApplId = (unsigned) b1_get_word(card->port);

		MsgLen = b1_get_slice(card->port, card->msgbuf);

		spin_unlock_irqrestore(&card->lock, flags);

		if (!(skb = alloc_skb(MsgLen, GFP_ATOMIC))) {

			printk(KERN_ERR "%s: incoming packet dropped\n",

					card->name);

			spin_unlock_irqrestore(&card->lock, flags);

		} else {

			memcpy(skb_put(skb, MsgLen), card->msgbuf, MsgLen);

			if (CAPIMSG_CMD(skb->data) == CAPI_DATA_B3_CONF)

				capilib_data_b3_conf(&cinfo->ncci_head, ApplId,

						     CAPIMSG_NCCI(skb->data),

						     CAPIMSG_MSGID(skb->data));



			spin_unlock_irqrestore(&card->lock, flags);

			capi_ctr_handle_message(ctrl, ApplId, skb);

		}

		break;
@@ -554,21 +556,17 @@ irqreturn_t b1_interrupt(int interrupt, void *devptr) 
		ApplId = b1_get_word(card->port);

		NCCI = b1_get_word(card->port);

		WindowSize = b1_get_word(card->port);

		spin_unlock_irqrestore(&card->lock, flags);



		capilib_new_ncci(&cinfo->ncci_head, ApplId, NCCI, WindowSize);



		spin_unlock_irqrestore(&card->lock, flags);

		break;



	case RECEIVE_FREE_NCCI:



		ApplId = b1_get_word(card->port);

		NCCI = b1_get_word(card->port);

		spin_unlock_irqrestore(&card->lock, flags);



		if (NCCI != 0xffffffff)

			capilib_free_ncci(&cinfo->ncci_head, ApplId, NCCI);

	       

		spin_unlock_irqrestore(&card->lock, flags);

		break;



	case RECEIVE_START: