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Subject[patch 06/26] sbp2: fix spinlock recursion
sbp2util_mark_command_completed takes a lock which was already taken by
sbp2scsi_complete_all_commands. This is a regression in Linux 2.6.15.
Reported by Kristian Harms at
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=187394

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/ieee1394/sbp2.c | 32 +++++++++++++++-----------------
1 file changed, 15 insertions(+), 17 deletions(-)

--- linux-2.6.16.1.orig/drivers/ieee1394/sbp2.c
+++ linux-2.6.16.1/drivers/ieee1394/sbp2.c
@@ -495,22 +495,17 @@ static struct sbp2_command_info *sbp2uti
/*
* This function finds the sbp2_command for a given outstanding SCpnt.
* Only looks at the inuse list.
+ * Must be called with scsi_id->sbp2_command_orb_lock held.
*/
-static struct sbp2_command_info *sbp2util_find_command_for_SCpnt(struct scsi_id_instance_data *scsi_id, void *SCpnt)
+static struct sbp2_command_info *sbp2util_find_command_for_SCpnt(
+ struct scsi_id_instance_data *scsi_id, void *SCpnt)
{
struct sbp2_command_info *command;
- unsigned long flags;

- spin_lock_irqsave(&scsi_id->sbp2_command_orb_lock, flags);
- if (!list_empty(&scsi_id->sbp2_command_orb_inuse)) {
- list_for_each_entry(command, &scsi_id->sbp2_command_orb_inuse, list) {
- if (command->Current_SCpnt == SCpnt) {
- spin_unlock_irqrestore(&scsi_id->sbp2_command_orb_lock, flags);
+ if (!list_empty(&scsi_id->sbp2_command_orb_inuse))
+ list_for_each_entry(command, &scsi_id->sbp2_command_orb_inuse, list)
+ if (command->Current_SCpnt == SCpnt)
return command;
- }
- }
- }
- spin_unlock_irqrestore(&scsi_id->sbp2_command_orb_lock, flags);
return NULL;
}

@@ -579,17 +574,15 @@ static void sbp2util_free_command_dma(st

/*
* This function moves a command to the completed orb list.
+ * Must be called with scsi_id->sbp2_command_orb_lock held.
*/
-static void sbp2util_mark_command_completed(struct scsi_id_instance_data *scsi_id,
- struct sbp2_command_info *command)
+static void sbp2util_mark_command_completed(
+ struct scsi_id_instance_data *scsi_id,
+ struct sbp2_command_info *command)
{
- unsigned long flags;
-
- spin_lock_irqsave(&scsi_id->sbp2_command_orb_lock, flags);
list_del(&command->list);
sbp2util_free_command_dma(command);
list_add_tail(&command->list, &scsi_id->sbp2_command_orb_completed);
- spin_unlock_irqrestore(&scsi_id->sbp2_command_orb_lock, flags);
}

/*
@@ -2177,7 +2170,9 @@ static int sbp2_handle_status_write(stru
* Matched status with command, now grab scsi command pointers and check status
*/
SCpnt = command->Current_SCpnt;
+ spin_lock_irqsave(&scsi_id->sbp2_command_orb_lock, flags);
sbp2util_mark_command_completed(scsi_id, command);
+ spin_unlock_irqrestore(&scsi_id->sbp2_command_orb_lock, flags);

if (SCpnt) {

@@ -2513,6 +2508,7 @@ static int sbp2scsi_abort(struct scsi_cm
(struct scsi_id_instance_data *)SCpnt->device->host->hostdata[0];
struct sbp2scsi_host_info *hi = scsi_id->hi;
struct sbp2_command_info *command;
+ unsigned long flags;

SBP2_ERR("aborting sbp2 command");
scsi_print_command(SCpnt);
@@ -2523,6 +2519,7 @@ static int sbp2scsi_abort(struct scsi_cm
* Right now, just return any matching command structures
* to the free pool.
*/
+ spin_lock_irqsave(&scsi_id->sbp2_command_orb_lock, flags);
command = sbp2util_find_command_for_SCpnt(scsi_id, SCpnt);
if (command) {
SBP2_DEBUG("Found command to abort");
@@ -2540,6 +2537,7 @@ static int sbp2scsi_abort(struct scsi_cm
command->Current_done(command->Current_SCpnt);
}
}
+ spin_unlock_irqrestore(&scsi_id->sbp2_command_orb_lock, flags);

/*
* Initiate a fetch agent reset.
--
-
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