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[char-misc-next v2 1/9] mei: drop redundant krealloc and checks in irq read

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From: Alexander Usyskin <alexander.usyskin@intel.com>

The read callback is always prepared with MTU-sized buffer and the FW
can't send more than the MTU in one message.
Checking for buffer existence and krealloc to increase receive buffer
size are redundant and may be safely discarded.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
V2: resend
 drivers/misc/mei/interrupt.c | 36 +++++++++++-------------------------
 1 file changed, 11 insertions(+), 25 deletions(-)

diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index 44ba90140725..36382d782e20 100644
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -102,18 +102,17 @@ int mei_cl_irq_read_msg(struct mei_cl *cl,
 {
 	struct mei_device *dev = cl->dev;
 	struct mei_cl_cb *cb;
-	unsigned char *buffer = NULL;
 	size_t buf_sz;
 
 	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 out;
+			goto discard;
 		}
 		cb = mei_cl_alloc_cb(cl, mei_cl_mtu(cl), MEI_FOP_READ, cl->fp);
 		if (!cb)
-			goto out;
+			goto discard;
 		list_add_tail(&cb->list, &cl->rd_pending);
 	}
 
@@ -121,14 +120,7 @@ int mei_cl_irq_read_msg(struct mei_cl *cl,
 		cl_dbg(dev, cl, "not connected\n");
 		list_move_tail(&cb->list, &complete_list->list);
 		cb->status = -ENODEV;
-		goto out;
-	}
-
-	if (cb->buf.size == 0 || cb->buf.data == NULL) {
-		cl_err(dev, cl, "response buffer is not allocated.\n");
-		list_move_tail(&cb->list, &complete_list->list);
-		cb->status = -ENOMEM;
-		goto out;
+		goto discard;
 	}
 
 	buf_sz = mei_hdr->length + cb->buf_idx;
@@ -139,25 +131,19 @@ int mei_cl_irq_read_msg(struct mei_cl *cl,
 
 		list_move_tail(&cb->list, &complete_list->list);
 		cb->status = -EMSGSIZE;
-		goto out;
+		goto discard;
 	}
 
 	if (cb->buf.size < buf_sz) {
 		cl_dbg(dev, cl, "message overflow. size %zu len %d idx %zu\n",
 			cb->buf.size, mei_hdr->length, cb->buf_idx);
-		buffer = krealloc(cb->buf.data, buf_sz, GFP_KERNEL);
 
-		if (!buffer) {
-			cb->status = -ENOMEM;
-			list_move_tail(&cb->list, &complete_list->list);
-			goto out;
-		}
-		cb->buf.data = buffer;
-		cb->buf.size = buf_sz;
+		list_move_tail(&cb->list, &complete_list->list);
+		cb->status = -EMSGSIZE;
+		goto discard;
 	}
 
-	buffer = cb->buf.data + cb->buf_idx;
-	mei_read_slots(dev, buffer, mei_hdr->length);
+	mei_read_slots(dev, cb->buf.data + cb->buf_idx, mei_hdr->length);
 
 	cb->buf_idx += mei_hdr->length;
 
@@ -169,10 +155,10 @@ int mei_cl_irq_read_msg(struct mei_cl *cl,
 		pm_request_autosuspend(dev->dev);
 	}
 
-out:
-	if (!buffer)
-		mei_irq_discard_msg(dev, mei_hdr);
+	return 0;
 
+discard:
+	mei_irq_discard_msg(dev, mei_hdr);
 	return 0;
 }
 
-- 
2.7.4

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Thread

[char-misc-next v2 0/9] mei: rx enhancements Tomas Winkler <tomas.winkler@intel.com> - 2016-07-26 00:10 +0200
  [char-misc-next v2 7/9] mei: amthif: drop mei_amthif_read Tomas Winkler <tomas.winkler@intel.com> - 2016-07-26 00:10 +0200
  [char-misc-next v2 6/9] mei: enqueue consecutive reads Tomas Winkler <tomas.winkler@intel.com> - 2016-07-26 00:10 +0200
  [char-misc-next v2 8/9] mei: drop unused file transaction states Tomas Winkler <tomas.winkler@intel.com> - 2016-07-26 00:10 +0200
  [char-misc-next v2 4/9] mei: use consistent naming for TX control flow credits Tomas Winkler <tomas.winkler@intel.com> - 2016-07-26 00:10 +0200
  [char-misc-next v2 9/9] mei: amthif: fix deadlock in initialization during a reset Tomas Winkler <tomas.winkler@intel.com> - 2016-07-26 00:10 +0200
  [char-misc-next v2 3/9] mei: rx flow control counter Tomas Winkler <tomas.winkler@intel.com> - 2016-07-26 00:10 +0200
  [char-misc-next v2 1/9] mei: drop redundant krealloc and checks in irq read Tomas Winkler <tomas.winkler@intel.com> - 2016-07-26 00:20 +0200
  [char-misc-next v2 2/9] mei: prepare read cb for fixed address clients on the receive path only. Tomas Winkler <tomas.winkler@intel.com> - 2016-07-26 00:20 +0200

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