rpms/kernel/devel linux-2.6-firewire-fix-unknown-write.patch, NONE, 1.1

[Kristian Høgsberg (krh)]

Author: krh

Update of /cvs/pkgs/rpms/kernel/devel
In directory cvs-int.fedora.redhat.com:/tmp/cvs-serv21397

Added Files:
	linux-2.6-firewire-fix-unknown-write.patch 
Log Message:
* Fri Aug 24 2007 Kristian Høgsberg <krh at redhat.com>
- Add patch for the "status write for unknown orb" firewire-sbp2 error.


linux-2.6-firewire-fix-unknown-write.patch:

--- NEW FILE linux-2.6-firewire-fix-unknown-write.patch ---
>From 1f9180034f8572f5cc40fb5eb9cd80780f7dc883 Mon Sep 17 00:00:00 2001
From: =?utf-8?q?Kristian=20H=C3=B8gsberg?= <krh at redhat.com>
Date: Fri, 24 Aug 2007 18:40:57 -0400
Subject: [PATCH] Add ref-counting for sbp2 orbs.
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit

This handles the case where we get the status write before getting the
complete_transaction callback.  In this case, we just assume that the
initial orb pointer transaction succeeded and finish the orb.  To
prevent the transaction callback from touching freed memory, we
ref-count the orb structures.

Signed-off-by: Kristian Høgsberg <krh at redhat.com>
---
 drivers/firewire/fw-sbp2.c |   49 +++++++++++++++++++++++++++++++++++--------
 1 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c
index 3e4a369..25d7b1a 100644
--- a/drivers/firewire/fw-sbp2.c
+++ b/drivers/firewire/fw-sbp2.c
@@ -159,6 +159,7 @@ struct sbp2_pointer {
 
 struct sbp2_orb {
 	struct fw_transaction t;
+	struct kref kref;
 	dma_addr_t request_bus;
 	int rcode;
 	struct sbp2_pointer pointer;
@@ -280,6 +281,14 @@ static const struct {
 };
 
 static void
+free_orb(struct kref *kref)
+{
+	struct sbp2_orb *orb = container_of(kref, struct sbp2_orb, kref);
+
+	kfree(orb);
+}
+
+static void
 sbp2_status_write(struct fw_card *card, struct fw_request *request,
 		  int tcode, int destination, int source,
 		  int generation, int speed,
@@ -312,8 +321,8 @@ sbp2_status_write(struct fw_card *card, struct fw_request *request,
 	spin_lock_irqsave(&card->lock, flags);
 	list_for_each_entry(orb, &sd->orb_list, link) {
 		if (STATUS_GET_ORB_HIGH(status) == 0 &&
-		    STATUS_GET_ORB_LOW(status) == orb->request_bus &&
-		    orb->rcode == RCODE_COMPLETE) {
+		    STATUS_GET_ORB_LOW(status) == orb->request_bus) {
+			orb->rcode = RCODE_COMPLETE;
 			list_del(&orb->link);
 			break;
 		}
@@ -325,6 +334,8 @@ sbp2_status_write(struct fw_card *card, struct fw_request *request,
 	else
 		fw_error("status write for unknown orb\n");
 
+	kref_put(&orb->kref, free_orb);
+
 	fw_send_response(card, request, RCODE_COMPLETE);
 }
 
@@ -335,13 +346,27 @@ complete_transaction(struct fw_card *card, int rcode,
 	struct sbp2_orb *orb = data;
 	unsigned long flags;
 
-	orb->rcode = rcode;
-	if (rcode != RCODE_COMPLETE) {
-		spin_lock_irqsave(&card->lock, flags);
+	/*
+	 * This is a little tricky.  We can get the status write for
+	 * the orb before we get this callback.  The status write
+	 * handler above will assume the orb pointer transaction was
+	 * successful and set the rcode to RCODE_COMPLETE for the orb.
+	 * So this callback only sets the rcode if it hasn't already
+	 * been set and only does the cleanup if the transaction
+	 * failed and we didn't already get a status write.
+	 */
+	spin_lock_irqsave(&card->lock, flags);
+
+	if (orb->rcode == -1)
+		orb->rcode = rcode;
+	if (orb->rcode != RCODE_COMPLETE) {
 		list_del(&orb->link);
-		spin_unlock_irqrestore(&card->lock, flags);
 		orb->callback(orb, NULL);
 	}
+
+	spin_unlock_irqrestore(&card->lock, flags);
+
+	kref_put(&orb->kref, free_orb);
 }
 
 static void
@@ -360,6 +385,10 @@ sbp2_send_orb(struct sbp2_orb *orb, struct fw_unit *unit,
 	list_add_tail(&orb->link, &sd->orb_list);
 	spin_unlock_irqrestore(&device->card->lock, flags);
 
+	/* Take a ref for the orb list and for the transaction callback. */
+	kref_get(&orb->kref);
+	kref_get(&orb->kref);
+
 	fw_send_request(device->card, &orb->t, TCODE_WRITE_BLOCK_REQUEST,
 			node_id, generation, device->max_speed, offset,
 			&orb->pointer, sizeof(orb->pointer),
@@ -416,6 +445,7 @@ sbp2_send_management_orb(struct fw_unit *unit, int node_id, int generation,
 	if (orb == NULL)
 		return -ENOMEM;
 
+	kref_init(&orb->base.kref);
 	orb->response_bus =
 		dma_map_single(device->card->device, &orb->response,
 			       sizeof(orb->response), DMA_FROM_DEVICE);
@@ -490,7 +520,7 @@ sbp2_send_management_orb(struct fw_unit *unit, int node_id, int generation,
 	if (response)
 		fw_memcpy_from_be32(response,
 				    orb->response, sizeof(orb->response));
-	kfree(orb);
+	kref_put(&orb->base.kref, free_orb);
 
 	return retval;
 }
@@ -886,7 +916,6 @@ complete_command_orb(struct sbp2_orb *base_orb, struct sbp2_status *status)
 
 	orb->cmd->result = result;
 	orb->done(orb->cmd);
-	kfree(orb);
 }
 
 static int sbp2_command_orb_map_scatterlist(struct sbp2_command_orb *orb)
@@ -1004,6 +1033,7 @@ static int sbp2_scsi_queuecommand(struct scsi_cmnd *cmd, scsi_done_fn_t done)
 
 	/* Initialize rcode to something not RCODE_COMPLETE. */
 	orb->base.rcode = -1;
+	kref_init(&orb->base.kref);
 
 	orb->unit = unit;
 	orb->done = done;
@@ -1048,10 +1078,11 @@ static int sbp2_scsi_queuecommand(struct scsi_cmnd *cmd, scsi_done_fn_t done)
 	sbp2_send_orb(&orb->base, unit, sd->node_id, sd->generation,
 		      sd->command_block_agent_address + SBP2_ORB_POINTER);
 
+	kref_put(&orb->base.kref, free_orb);
 	return 0;
 
  fail_mapping:
-	kfree(orb);
+	kref_put(&orb->base.kref, free_orb);
  fail_alloc:
 	return SCSI_MLQUEUE_HOST_BUSY;
 }
-- 
1.5.2.GIT