target: Fix interrupt context bug with stats_lock and core_tmr_alloc_req

commit 53ab6709b4d35b1924240854d794482fd7d33d4a upstream.

This patch fixes two bugs wrt to the interrupt context usage of target
core with HW target mode drivers.  It first converts the usage of struct
se_device->stats_lock in transport_get_lun_for_cmd() and core_tmr_lun_reset()
to properly use spin_lock_irq() to address an BUG with CONFIG_LOCKDEP_SUPPORT=y
enabled.

This patch also adds a 'in_interrupt()' check to allow GFP_ATOMIC usage from
core_tmr_alloc_req() to fix a 'sleeping in interrupt context' BUG with HW
target fabrics that require this logic to function.

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: James Bottomley <jbottomley@parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 5da051a07fa30a0103fa95f00d2d757b881ac82b..0e0257bf5b78d00af25d15dd0bbb364b33328cb7 100644 (file)
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -151,13 +151,13 @@ out:
 
        {
        struct se_device *dev = se_lun->lun_se_dev;
-       spin_lock(&dev->stats_lock);
+       spin_lock_irq(&dev->stats_lock);
        dev->num_cmds++;
        if (se_cmd->data_direction == DMA_TO_DEVICE)
                dev->write_bytes += se_cmd->data_length;
        else if (se_cmd->data_direction == DMA_FROM_DEVICE)
                dev->read_bytes += se_cmd->data_length;
-       spin_unlock(&dev->stats_lock);
+       spin_unlock_irq(&dev->stats_lock);
        }
 
        /*

diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index 4a109835e4203995bf8c4ea0784639321d7013f5..59b8b9c5ad72a272e1c228474f6b241b6a70913b 100644 (file)
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -55,7 +55,8 @@ struct se_tmr_req *core_tmr_alloc_req(
 {
        struct se_tmr_req *tmr;
 
-       tmr = kmem_cache_zalloc(se_tmr_req_cache, GFP_KERNEL);
+       tmr = kmem_cache_zalloc(se_tmr_req_cache, (in_interrupt()) ?
+                                       GFP_ATOMIC : GFP_KERNEL);
        if (!(tmr)) {
                printk(KERN_ERR "Unable to allocate struct se_tmr_req\n");
                return ERR_PTR(-ENOMEM);
@@ -398,9 +399,9 @@ int core_tmr_lun_reset(
                printk(KERN_INFO "LUN_RESET: SCSI-2 Released reservation\n");
        }
 
-       spin_lock(&dev->stats_lock);
+       spin_lock_irq(&dev->stats_lock);
        dev->num_resets++;
-       spin_unlock(&dev->stats_lock);
+       spin_unlock_irq(&dev->stats_lock);
 
        DEBUG_LR("LUN_RESET: %s for [%s] Complete\n",
                        (preempt_and_abort_list) ? "Preempt" : "TMR",