[SCSI] megaraid_sas: switch fw_outstanding to an atomic_t
This patch( originally submitted by Christoph Hellwig) removes
instance_lock and changes fw_outstanding variable data type to
atomic_t.
Signed-off-by: Sumant Patro <Sumant.Patro@lsil.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/Documentation/scsi/ChangeLog.megaraid_sas b/Documentation/scsi/ChangeLog.megaraid_sas
index 2dafa63..0a85a7e 100644
--- a/Documentation/scsi/ChangeLog.megaraid_sas
+++ b/Documentation/scsi/ChangeLog.megaraid_sas
@@ -1,3 +1,16 @@
+
+1 Release Date : Wed Feb 03 14:31:44 PST 2006 - Sumant Patro <Sumant.Patro@lsil.com>
+2 Current Version : 00.00.02.04
+3 Older Version : 00.00.02.04
+
+i. Remove superflous instance_lock
+
+ gets rid of the otherwise superflous instance_lock and avoids an unsave
+ unsynchronized access in the error handler.
+
+ - Christoph Hellwig <hch@lst.de>
+
+
1 Release Date : Wed Feb 03 14:31:44 PST 2006 - Sumant Patro <Sumant.Patro@lsil.com>
2 Current Version : 00.00.02.04
3 Older Version : 00.00.02.04
diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index 3972946..0c9516f 100644
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -741,7 +741,6 @@
megasas_queue_command(struct scsi_cmnd *scmd, void (*done) (struct scsi_cmnd *))
{
u32 frame_count;
- unsigned long flags;
struct megasas_cmd *cmd;
struct megasas_instance *instance;
@@ -776,9 +775,7 @@
/*
* Issue the command to the FW
*/
- spin_lock_irqsave(&instance->instance_lock, flags);
- instance->fw_outstanding++;
- spin_unlock_irqrestore(&instance->instance_lock, flags);
+ atomic_inc(&instance->fw_outstanding);
instance->instancet->fire_cmd(cmd->frame_phys_addr ,cmd->frame_count-1,instance->reg_set);
@@ -826,19 +823,20 @@
for (i = 0; i < wait_time; i++) {
- if (!instance->fw_outstanding)
+ int outstanding = atomic_read(&instance->fw_outstanding);
+
+ if (!outstanding)
break;
if (!(i % MEGASAS_RESET_NOTICE_INTERVAL)) {
printk(KERN_NOTICE "megasas: [%2d]waiting for %d "
- "commands to complete\n", i,
- instance->fw_outstanding);
+ "commands to complete\n",i,outstanding);
}
msleep(1000);
}
- if (instance->fw_outstanding) {
+ if (atomic_read(&instance->fw_outstanding)) {
instance->hw_crit_error = 1;
return FAILED;
}
@@ -1050,7 +1048,6 @@
{
int exception = 0;
struct megasas_header *hdr = &cmd->frame->hdr;
- unsigned long flags;
if (cmd->scmd) {
cmd->scmd->SCp.ptr = (char *)0;
@@ -1082,9 +1079,7 @@
if (exception) {
- spin_lock_irqsave(&instance->instance_lock, flags);
- instance->fw_outstanding--;
- spin_unlock_irqrestore(&instance->instance_lock, flags);
+ atomic_dec(&instance->fw_outstanding);
megasas_unmap_sgbuf(instance, cmd);
cmd->scmd->scsi_done(cmd->scmd);
@@ -1132,9 +1127,7 @@
break;
}
- spin_lock_irqsave(&instance->instance_lock, flags);
- instance->fw_outstanding--;
- spin_unlock_irqrestore(&instance->instance_lock, flags);
+ atomic_dec(&instance->fw_outstanding);
megasas_unmap_sgbuf(instance, cmd);
cmd->scmd->scsi_done(cmd->scmd);
@@ -2171,11 +2164,12 @@
*/
INIT_LIST_HEAD(&instance->cmd_pool);
+ atomic_set(&instance->fw_outstanding,0);
+
init_waitqueue_head(&instance->int_cmd_wait_q);
init_waitqueue_head(&instance->abort_cmd_wait_q);
spin_lock_init(&instance->cmd_pool_lock);
- spin_lock_init(&instance->instance_lock);
sema_init(&instance->aen_mutex, 1);
sema_init(&instance->ioctl_sem, MEGASAS_INT_CMDS);
diff --git a/drivers/scsi/megaraid/megaraid_sas.h b/drivers/scsi/megaraid/megaraid_sas.h
index 89639f0..927d6ff 100644
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -1077,9 +1077,8 @@
struct pci_dev *pdev;
u32 unique_id;
- u32 fw_outstanding;
+ atomic_t fw_outstanding;
u32 hw_crit_error;
- spinlock_t instance_lock;
struct megasas_instance_template *instancet;
};