Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 685 insertions, 0 deletions

diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
new file mode 100644
index 000000000..4262965c4
--- /dev/null
+++ b/drivers/misc/mei/interrupt.c
@@ -0,0 +1,685 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2003-2018, Intel Corporation. All rights reserved.
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ */
+
+#include <linux/export.h>
+#include <linux/kthread.h>
+#include <linux/interrupt.h>
+#include <linux/fs.h>
+#include <linux/jiffies.h>
+#include <linux/slab.h>
+#include <linux/pm_runtime.h>
+
+#include <linux/mei.h>
+
+#include "mei_dev.h"
+#include "hbm.h"
+#include "client.h"
+
+
+/**
+ * mei_irq_compl_handler - dispatch complete handlers
+ *	for the completed callbacks
+ *
+ * @dev: mei device
+ * @cmpl_list: list of completed cbs
+ */
+void mei_irq_compl_handler(struct mei_device *dev, struct list_head *cmpl_list)
+{
+	struct mei_cl_cb *cb, *next;
+	struct mei_cl *cl;
+
+	list_for_each_entry_safe(cb, next, cmpl_list, list) {
+		cl = cb->cl;
+		list_del_init(&cb->list);
+
+		cl_dbg(dev, cl, "completing call back.\n");
+		mei_cl_complete(cl, cb);
+	}
+}
+EXPORT_SYMBOL_GPL(mei_irq_compl_handler);
+
+/**
+ * mei_cl_hbm_equal - check if hbm is addressed to the client
+ *
+ * @cl: host client
+ * @mei_hdr: header of mei client message
+ *
+ * Return: true if matches, false otherwise
+ */
+static inline int mei_cl_hbm_equal(struct mei_cl *cl,
+			struct mei_msg_hdr *mei_hdr)
+{
+	return  mei_cl_host_addr(cl) == mei_hdr->host_addr &&
+		mei_cl_me_id(cl) == mei_hdr->me_addr;
+}
+
+/**
+ * mei_irq_discard_msg  - discard received message
+ *
+ * @dev: mei device
+ * @hdr: message header
+ * @discard_len: the length of the message to discard (excluding header)
+ */
+static void mei_irq_discard_msg(struct mei_device *dev, struct mei_msg_hdr *hdr,
+				size_t discard_len)
+{
+	if (hdr->dma_ring) {
+		mei_dma_ring_read(dev, NULL,
+				  hdr->extension[dev->rd_msg_hdr_count - 2]);
+		discard_len = 0;
+	}
+	/*
+	 * no need to check for size as it is guaranteed
+	 * that length fits into rd_msg_buf
+	 */
+	mei_read_slots(dev, dev->rd_msg_buf, discard_len);
+	dev_dbg(&dev->dev, "discarding message " MEI_HDR_FMT "\n",
+		MEI_HDR_PRM(hdr));
+}
+
+/**
+ * mei_cl_irq_read_msg - process client message
+ *
+ * @cl: reading client
+ * @mei_hdr: header of mei client message
+ * @meta: extend meta header
+ * @cmpl_list: completion list
+ *
+ * Return: always 0
+ */
+static int mei_cl_irq_read_msg(struct mei_cl *cl,
+			       struct mei_msg_hdr *mei_hdr,
+			       struct mei_ext_meta_hdr *meta,
+			       struct list_head *cmpl_list)
+{
+	struct mei_device *dev = cl->dev;
+	struct mei_cl_cb *cb;
+
+	struct mei_ext_hdr_vtag *vtag_hdr = NULL;
+	struct mei_ext_hdr_gsc_f2h *gsc_f2h = NULL;
+
+	size_t buf_sz;
+	u32 length;
+	u32 ext_len;
+
+	length = mei_hdr->length;
+	ext_len = 0;
+	if (mei_hdr->extended) {
+		ext_len = sizeof(*meta) + mei_slots2data(meta->size);
+		length -= ext_len;
+	}
+
+	cb = list_first_entry_or_null(&cl->rd_pending, struct mei_cl_cb, list);
+	if (!cb) {
+		if (!mei_cl_is_fixed_address(cl)) {
+			cl_err(dev, cl, "pending read cb not found\n");
+			goto discard;
+		}
+		cb = mei_cl_alloc_cb(cl, mei_cl_mtu(cl), MEI_FOP_READ, cl->fp);
+		if (!cb)
+			goto discard;
+		list_add_tail(&cb->list, &cl->rd_pending);
+	}
+
+	if (mei_hdr->extended) {
+		struct mei_ext_hdr *ext = mei_ext_begin(meta);
+		do {
+			switch (ext->type) {
+			case MEI_EXT_HDR_VTAG:
+				vtag_hdr = (struct mei_ext_hdr_vtag *)ext;
+				break;
+			case MEI_EXT_HDR_GSC:
+				gsc_f2h = (struct mei_ext_hdr_gsc_f2h *)ext;
+				cb->ext_hdr = (struct mei_ext_hdr *) kzalloc_obj(*gsc_f2h);
+				if (!cb->ext_hdr) {
+					cb->status = -ENOMEM;
+					goto discard;
+				}
+				break;
+			case MEI_EXT_HDR_NONE:
+				fallthrough;
+			default:
+				cl_err(dev, cl, "unknown extended header\n");
+				cb->status = -EPROTO;
+				break;
+			}
+
+			ext = mei_ext_next(ext);
+		} while (!mei_ext_last(meta, ext));
+
+		if (!vtag_hdr && !gsc_f2h) {
+			cl_dbg(dev, cl, "no vtag or gsc found in extended header.\n");
+			cb->status = -EPROTO;
+			goto discard;
+		}
+	}
+
+	if (vtag_hdr) {
+		cl_dbg(dev, cl, "vtag: %d\n", vtag_hdr->vtag);
+		if (cb->vtag && cb->vtag != vtag_hdr->vtag) {
+			cl_err(dev, cl, "mismatched tag: %d != %d\n",
+			       cb->vtag, vtag_hdr->vtag);
+			cb->status = -EPROTO;
+			goto discard;
+		}
+		cb->vtag = vtag_hdr->vtag;
+	}
+
+	if (gsc_f2h) {
+		u32 ext_hdr_len = mei_ext_hdr_len(&gsc_f2h->hdr);
+
+		if (!dev->hbm_f_gsc_supported) {
+			cl_err(dev, cl, "gsc extended header is not supported\n");
+			cb->status = -EPROTO;
+			goto discard;
+		}
+
+		if (length) {
+			cl_err(dev, cl, "no data allowed in cb with gsc\n");
+			cb->status = -EPROTO;
+			goto discard;
+		}
+		if (ext_hdr_len > sizeof(*gsc_f2h)) {
+			cl_err(dev, cl, "gsc extended header is too big %u\n", ext_hdr_len);
+			cb->status = -EPROTO;
+			goto discard;
+		}
+		memcpy(cb->ext_hdr, gsc_f2h, ext_hdr_len);
+	}
+
+	if (!mei_cl_is_connected(cl)) {
+		cl_dbg(dev, cl, "not connected\n");
+		cb->status = -ENODEV;
+		goto discard;
+	}
+
+	if (mei_hdr->dma_ring)
+		length = mei_hdr->extension[mei_data2slots(ext_len)];
+
+	buf_sz = length + cb->buf_idx;
+	/* catch for integer overflow */
+	if (buf_sz < cb->buf_idx) {
+		cl_err(dev, cl, "message is too big len %d idx %zu\n",
+		       length, cb->buf_idx);
+		cb->status = -EMSGSIZE;
+		goto discard;
+	}
+
+	if (cb->buf.size < buf_sz) {
+		cl_dbg(dev, cl, "message overflow. size %zu len %d idx %zu\n",
+			cb->buf.size, length, cb->buf_idx);
+		cb->status = -EMSGSIZE;
+		goto discard;
+	}
+
+	if (mei_hdr->dma_ring) {
+		mei_dma_ring_read(dev, cb->buf.data + cb->buf_idx, length);
+		/*  for DMA read 0 length to generate interrupt to the device */
+		mei_read_slots(dev, cb->buf.data + cb->buf_idx, 0);
+	} else {
+		mei_read_slots(dev, cb->buf.data + cb->buf_idx, length);
+	}
+
+	cb->buf_idx += length;
+
+	if (mei_hdr->msg_complete) {
+		cl_dbg(dev, cl, "completed read length = %zu\n", cb->buf_idx);
+		list_move_tail(&cb->list, cmpl_list);
+	} else {
+		pm_request_autosuspend(dev->parent);
+	}
+
+	return 0;
+
+discard:
+	if (cb)
+		list_move_tail(&cb->list, cmpl_list);
+	mei_irq_discard_msg(dev, mei_hdr, length);
+	return 0;
+}
+
+/**
+ * mei_cl_irq_disconnect_rsp - send disconnection response message
+ *
+ * @cl: client
+ * @cb: callback block.
+ * @cmpl_list: complete list.
+ *
+ * Return: 0, OK; otherwise, error.
+ */
+static int mei_cl_irq_disconnect_rsp(struct mei_cl *cl, struct mei_cl_cb *cb,
+				     struct list_head *cmpl_list)
+{
+	struct mei_device *dev = cl->dev;
+	u32 msg_slots;
+	int slots;
+	int ret;
+
+	msg_slots = mei_hbm2slots(sizeof(struct hbm_client_connect_response));
+	slots = mei_hbuf_empty_slots(dev);
+	if (slots < 0)
+		return -EOVERFLOW;
+
+	if ((u32)slots < msg_slots)
+		return -EMSGSIZE;
+
+	ret = mei_hbm_cl_disconnect_rsp(dev, cl);
+	list_move_tail(&cb->list, cmpl_list);
+
+	return ret;
+}
+
+/**
+ * mei_cl_irq_read - processes client read related operation from the
+ *	interrupt thread context - request for flow control credits
+ *
+ * @cl: client
+ * @cb: callback block.
+ * @cmpl_list: complete list.
+ *
+ * Return: 0, OK; otherwise, error.
+ */
+static int mei_cl_irq_read(struct mei_cl *cl, struct mei_cl_cb *cb,
+			   struct list_head *cmpl_list)
+{
+	struct mei_device *dev = cl->dev;
+	u32 msg_slots;
+	int slots;
+	int ret;
+
+	if (!list_empty(&cl->rd_pending))
+		return 0;
+
+	msg_slots = mei_hbm2slots(sizeof(struct hbm_flow_control));
+	slots = mei_hbuf_empty_slots(dev);
+	if (slots < 0)
+		return -EOVERFLOW;
+
+	if ((u32)slots < msg_slots)
+		return -EMSGSIZE;
+
+	ret = mei_hbm_cl_flow_control_req(dev, cl);
+	if (ret) {
+		cl->status = ret;
+		cb->buf_idx = 0;
+		list_move_tail(&cb->list, cmpl_list);
+		return ret;
+	}
+
+	pm_request_autosuspend(dev->parent);
+
+	list_move_tail(&cb->list, &cl->rd_pending);
+
+	return 0;
+}
+
+static inline bool hdr_is_hbm(struct mei_msg_hdr *mei_hdr)
+{
+	return mei_hdr->host_addr == 0 && mei_hdr->me_addr == 0;
+}
+
+static inline bool hdr_is_fixed(struct mei_msg_hdr *mei_hdr)
+{
+	return mei_hdr->host_addr == 0 && mei_hdr->me_addr != 0;
+}
+
+static inline int hdr_is_valid(u32 msg_hdr)
+{
+	struct mei_msg_hdr *mei_hdr;
+	u32 expected_len = 0;
+
+	mei_hdr = (struct mei_msg_hdr *)&msg_hdr;
+	if (!msg_hdr || mei_hdr->reserved)
+		return -EBADMSG;
+
+	if (mei_hdr->dma_ring)
+		expected_len += MEI_SLOT_SIZE;
+	if (mei_hdr->extended)
+		expected_len += MEI_SLOT_SIZE;
+	if (mei_hdr->length < expected_len)
+		return -EBADMSG;
+
+	return 0;
+}
+
+/**
+ * mei_irq_read_handler - bottom half read routine after ISR to
+ * handle the read processing.
+ *
+ * @dev: the device structure
+ * @cmpl_list: An instance of our list structure
+ * @slots: slots to read.
+ *
+ * Return: 0 on success, <0 on failure.
+ */
+int mei_irq_read_handler(struct mei_device *dev,
+			 struct list_head *cmpl_list, s32 *slots)
+{
+	struct mei_msg_hdr *mei_hdr;
+	struct mei_ext_meta_hdr *meta_hdr = NULL;
+	struct mei_cl *cl;
+	int ret;
+	u32 hdr_size_left;
+	u32 hdr_size_ext;
+	int i;
+	int ext_hdr_end;
+
+	if (!dev->rd_msg_hdr[0]) {
+		dev->rd_msg_hdr[0] = mei_read_hdr(dev);
+		dev->rd_msg_hdr_count = 1;
+		(*slots)--;
+		dev_dbg(&dev->dev, "slots =%08x.\n", *slots);
+
+		ret = hdr_is_valid(dev->rd_msg_hdr[0]);
+		if (ret) {
+			dev_err(&dev->dev, "corrupted message header 0x%08X\n",
+				dev->rd_msg_hdr[0]);
+			goto end;
+		}
+	}
+
+	mei_hdr = (struct mei_msg_hdr *)dev->rd_msg_hdr;
+	dev_dbg(&dev->dev, MEI_HDR_FMT, MEI_HDR_PRM(mei_hdr));
+
+	if (mei_slots2data(*slots) < mei_hdr->length) {
+		dev_err(&dev->dev, "less data available than length=%08x.\n",
+				*slots);
+		/* we can't read the message */
+		ret = -ENODATA;
+		goto end;
+	}
+
+	ext_hdr_end = 1;
+	hdr_size_left = mei_hdr->length;
+
+	if (mei_hdr->extended) {
+		if (!dev->rd_msg_hdr[1]) {
+			dev->rd_msg_hdr[1] = mei_read_hdr(dev);
+			dev->rd_msg_hdr_count++;
+			(*slots)--;
+			dev_dbg(&dev->dev, "extended header is %08x\n", dev->rd_msg_hdr[1]);
+		}
+		meta_hdr = ((struct mei_ext_meta_hdr *)&dev->rd_msg_hdr[1]);
+		if (check_add_overflow((u32)sizeof(*meta_hdr),
+				       mei_slots2data(meta_hdr->size),
+				       &hdr_size_ext)) {
+			dev_err(&dev->dev, "extended message size too big %d\n",
+				meta_hdr->size);
+			return -EBADMSG;
+		}
+		if (hdr_size_left < hdr_size_ext) {
+			dev_err(&dev->dev, "corrupted message header len %d\n",
+				mei_hdr->length);
+			return -EBADMSG;
+		}
+		hdr_size_left -= hdr_size_ext;
+
+		ext_hdr_end = meta_hdr->size + 2;
+		for (i = dev->rd_msg_hdr_count; i < ext_hdr_end; i++) {
+			dev->rd_msg_hdr[i] = mei_read_hdr(dev);
+			dev_dbg(&dev->dev, "extended header %d is %08x\n", i,
+				dev->rd_msg_hdr[i]);
+			dev->rd_msg_hdr_count++;
+			(*slots)--;
+		}
+	}
+
+	if (mei_hdr->dma_ring) {
+		if (hdr_size_left != sizeof(dev->rd_msg_hdr[ext_hdr_end])) {
+			dev_err(&dev->dev, "corrupted message header len %d\n",
+				mei_hdr->length);
+			return -EBADMSG;
+		}
+
+		dev->rd_msg_hdr[ext_hdr_end] = mei_read_hdr(dev);
+		dev->rd_msg_hdr_count++;
+		(*slots)--;
+		mei_hdr->length -= sizeof(dev->rd_msg_hdr[ext_hdr_end]);
+	}
+
+	/*  HBM message */
+	if (hdr_is_hbm(mei_hdr)) {
+		ret = mei_hbm_dispatch(dev, mei_hdr);
+		if (ret) {
+			dev_dbg(&dev->dev, "mei_hbm_dispatch failed ret = %d\n", ret);
+			goto end;
+		}
+		goto reset_slots;
+	}
+
+	/* find recipient cl */
+	list_for_each_entry(cl, &dev->file_list, link) {
+		if (mei_cl_hbm_equal(cl, mei_hdr)) {
+			cl_dbg(dev, cl, "got a message\n");
+			ret = mei_cl_irq_read_msg(cl, mei_hdr, meta_hdr, cmpl_list);
+			goto reset_slots;
+		}
+	}
+
+	/* if no recipient cl was found we assume corrupted header */
+	/* A message for not connected fixed address clients
+	 * should be silently discarded
+	 * On power down client may be force cleaned,
+	 * silently discard such messages
+	 */
+	if (hdr_is_fixed(mei_hdr) ||
+	    dev->dev_state == MEI_DEV_POWER_DOWN) {
+		mei_irq_discard_msg(dev, mei_hdr, mei_hdr->length);
+		ret = 0;
+		goto reset_slots;
+	}
+	dev_err(&dev->dev, "no destination client found 0x%08X\n", dev->rd_msg_hdr[0]);
+	ret = -EBADMSG;
+	goto end;
+
+reset_slots:
+	/* reset the number of slots and header */
+	memset(dev->rd_msg_hdr, 0, sizeof(dev->rd_msg_hdr));
+	dev->rd_msg_hdr_count = 0;
+	*slots = mei_count_full_read_slots(dev);
+	if (*slots == -EOVERFLOW) {
+		/* overflow - reset */
+		dev_err(&dev->dev, "resetting due to slots overflow.\n");
+		/* set the event since message has been read */
+		ret = -ERANGE;
+		goto end;
+	}
+end:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(mei_irq_read_handler);
+
+
+/**
+ * mei_irq_write_handler -  dispatch write requests
+ *  after irq received
+ *
+ * @dev: the device structure
+ * @cmpl_list: An instance of our list structure
+ *
+ * Return: 0 on success, <0 on failure.
+ */
+int mei_irq_write_handler(struct mei_device *dev, struct list_head *cmpl_list)
+{
+
+	struct mei_cl *cl;
+	struct mei_cl_cb *cb, *next;
+	s32 slots;
+	int ret;
+
+
+	if (!mei_hbuf_acquire(dev))
+		return 0;
+
+	slots = mei_hbuf_empty_slots(dev);
+	if (slots < 0)
+		return -EOVERFLOW;
+
+	if (slots == 0)
+		return -EMSGSIZE;
+
+	/* complete all waiting for write CB */
+	dev_dbg(&dev->dev, "complete all waiting for write cb.\n");
+
+	list_for_each_entry_safe(cb, next, &dev->write_waiting_list, list) {
+		cl = cb->cl;
+
+		cl->status = 0;
+		cl_dbg(dev, cl, "MEI WRITE COMPLETE\n");
+		cl->writing_state = MEI_WRITE_COMPLETE;
+		list_move_tail(&cb->list, cmpl_list);
+	}
+
+	/* complete control write list CB */
+	dev_dbg(&dev->dev, "complete control write list cb.\n");
+	list_for_each_entry_safe(cb, next, &dev->ctrl_wr_list, list) {
+		cl = cb->cl;
+		switch (cb->fop_type) {
+		case MEI_FOP_DISCONNECT:
+			/* send disconnect message */
+			ret = mei_cl_irq_disconnect(cl, cb, cmpl_list);
+			if (ret)
+				return ret;
+
+			break;
+		case MEI_FOP_READ:
+			/* send flow control message */
+			ret = mei_cl_irq_read(cl, cb, cmpl_list);
+			if (ret)
+				return ret;
+
+			break;
+		case MEI_FOP_CONNECT:
+			/* connect message */
+			ret = mei_cl_irq_connect(cl, cb, cmpl_list);
+			if (ret)
+				return ret;
+
+			break;
+		case MEI_FOP_DISCONNECT_RSP:
+			/* send disconnect resp */
+			ret = mei_cl_irq_disconnect_rsp(cl, cb, cmpl_list);
+			if (ret)
+				return ret;
+			break;
+
+		case MEI_FOP_NOTIFY_START:
+		case MEI_FOP_NOTIFY_STOP:
+			ret = mei_cl_irq_notify(cl, cb, cmpl_list);
+			if (ret)
+				return ret;
+			break;
+		case MEI_FOP_DMA_MAP:
+			ret = mei_cl_irq_dma_map(cl, cb, cmpl_list);
+			if (ret)
+				return ret;
+			break;
+		case MEI_FOP_DMA_UNMAP:
+			ret = mei_cl_irq_dma_unmap(cl, cb, cmpl_list);
+			if (ret)
+				return ret;
+			break;
+		default:
+			BUG();
+		}
+
+	}
+	/* complete  write list CB */
+	dev_dbg(&dev->dev, "complete write list cb.\n");
+	list_for_each_entry_safe(cb, next, &dev->write_list, list) {
+		cl = cb->cl;
+		ret = mei_cl_irq_write(cl, cb, cmpl_list);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mei_irq_write_handler);
+
+
+/**
+ * mei_connect_timeout  - connect/disconnect timeouts
+ *
+ * @cl: host client
+ */
+static void mei_connect_timeout(struct mei_cl *cl)
+{
+	struct mei_device *dev = cl->dev;
+
+	if (cl->state == MEI_FILE_CONNECTING) {
+		if (dev->hbm_f_dot_supported) {
+			cl->state = MEI_FILE_DISCONNECT_REQUIRED;
+			wake_up(&cl->wait);
+			return;
+		}
+	}
+	mei_reset(dev);
+}
+
+#define MEI_STALL_TIMER_FREQ (2 * HZ)
+/**
+ * mei_schedule_stall_timer - re-arm stall_timer work
+ *
+ * @dev: the device structure
+ *
+ * Schedule stall timer
+ */
+void mei_schedule_stall_timer(struct mei_device *dev)
+{
+	schedule_delayed_work(&dev->timer_work, MEI_STALL_TIMER_FREQ);
+}
+
+/**
+ * mei_timer - timer function.
+ *
+ * @work: pointer to the work_struct structure
+ *
+ */
+void mei_timer(struct work_struct *work)
+{
+	struct mei_cl *cl;
+	struct mei_device *dev = container_of(work,
+					struct mei_device, timer_work.work);
+	bool reschedule_timer = false;
+
+	mutex_lock(&dev->device_lock);
+
+	/* Catch interrupt stalls during HBM init handshake */
+	if (dev->dev_state == MEI_DEV_INIT_CLIENTS &&
+	    dev->hbm_state != MEI_HBM_IDLE) {
+
+		if (dev->init_clients_timer) {
+			if (--dev->init_clients_timer == 0) {
+				dev_err(&dev->dev, "timer: init clients timeout hbm_state = %d.\n",
+					dev->hbm_state);
+				mei_reset(dev);
+				goto out;
+			}
+			reschedule_timer = true;
+		}
+	}
+
+	if (dev->dev_state != MEI_DEV_ENABLED)
+		goto out;
+
+	/*** connect/disconnect timeouts ***/
+	list_for_each_entry(cl, &dev->file_list, link) {
+		if (cl->timer_count) {
+			if (--cl->timer_count == 0) {
+				dev_err(&dev->dev, "timer: connect/disconnect timeout.\n");
+				mei_connect_timeout(cl);
+				goto out;
+			}
+			reschedule_timer = true;
+		}
+	}
+
+out:
+	if (dev->dev_state != MEI_DEV_DISABLED && reschedule_timer)
+		mei_schedule_stall_timer(dev);
+
+	mutex_unlock(&dev->device_lock);
+}