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Commit 1e7de68c authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

[SCSI] target: Fix interrupt context bug with stats_lock and core_tmr_alloc_req 



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: default avatarNicholas Bellinger <nab@linux-iscsi.org>
Cc: stable@kernel.org
Signed-off-by: default avatarJames Bottomley <jbottomley@parallels.com>
parent 4a8fcc2c

drivers/target/target_core_device.c

+2 −2
Original line number Diff line number Diff line
@@ -150,13 +150,13 @@ int transport_get_lun_for_cmd( 


	{

	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);

	}



	/*

drivers/target/target_core_tmr.c

+4 −3
Original line number Diff line number Diff line
@@ -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",