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Commit a3ae39c0 authored by Andreas Herrmann's avatar Andreas Herrmann Committed by Linus Torvalds
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[PATCH] s390: qdio memory allocations 



Avoid memory allocation with GFP_KERNEL in qdio_establish/qdio_shutdown.  Use
memory pool instead.  (Otherwise this can lead to an I/O stall where qdio
waits for a free page and zfcp waits for end of error recovery in low memory
situations.)

Signed-off-by: default avatarAndreas Herrmann <aherrman@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 28f22378

drivers/s390/cio/qdio.c

+24 −6
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include <linux/kernel.h>

#include <linux/proc_fs.h>

#include <linux/timer.h>

#include <linux/mempool.h>



#include <asm/ccwdev.h>

#include <asm/io.h>
@@ -80,6 +81,8 @@ static int indicator_used[INDICATORS_PER_CACHELINE]; 
static __u32 * volatile indicators;

static __u32 volatile spare_indicator;

static atomic_t spare_indicator_usecount;

#define QDIO_MEMPOOL_SCSSC_ELEMENTS 2

static mempool_t *qdio_mempool_scssc;



static debug_info_t *qdio_dbf_setup;

static debug_info_t *qdio_dbf_sbal;
@@ -2304,7 +2307,7 @@ qdio_get_ssqd_information(struct qdio_irq *irq_ptr) 


	QDIO_DBF_TEXT0(0,setup,"getssqd");

	qdioac = 0;

	ssqd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);

	ssqd_area = mempool_alloc(qdio_mempool_scssc, GFP_ATOMIC);

	if (!ssqd_area) {

	        QDIO_PRINT_WARN("Could not get memory for chsc. Using all " \

				"SIGAs for sch x%x.\n", irq_ptr->schid.sch_no);
@@ -2364,7 +2367,7 @@ qdio_get_ssqd_information(struct qdio_irq *irq_ptr) 
out:

	qdio_check_subchannel_qebsm(irq_ptr, qdioac,

				    ssqd_area->sch_token);

	free_page ((unsigned long) ssqd_area);

	mempool_free(ssqd_area, qdio_mempool_scssc);

	irq_ptr->qdioac = qdioac;

}
@@ -2458,7 +2461,7 @@ tiqdio_set_subchannel_ind(struct qdio_irq *irq_ptr, int reset_to_zero) 
			virt_to_phys((volatile void *)irq_ptr->dev_st_chg_ind);

	}



	scssc_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);

	scssc_area = mempool_alloc(qdio_mempool_scssc, GFP_ATOMIC);

	if (!scssc_area) {

		QDIO_PRINT_WARN("No memory for setting indicators on " \

				"subchannel 0.%x.%x.\n",
@@ -2514,7 +2517,7 @@ tiqdio_set_subchannel_ind(struct qdio_irq *irq_ptr, int reset_to_zero) 
	QDIO_DBF_HEX2(0,setup,&real_addr_dev_st_chg_ind,sizeof(unsigned long));

	result = 0;

out:

	free_page ((unsigned long) scssc_area);

	mempool_free(scssc_area, qdio_mempool_scssc);

	return result;



}
@@ -2543,7 +2546,7 @@ tiqdio_set_delay_target(struct qdio_irq *irq_ptr, unsigned long delay_target) 
	if (!irq_ptr->is_thinint_irq)

		return -ENODEV;



	scsscf_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);

	scsscf_area = mempool_alloc(qdio_mempool_scssc, GFP_ATOMIC);

	if (!scsscf_area) {

		QDIO_PRINT_WARN("No memory for setting delay target on " \

				"subchannel 0.%x.%x.\n",
@@ -2581,7 +2584,7 @@ tiqdio_set_delay_target(struct qdio_irq *irq_ptr, unsigned long delay_target) 
	QDIO_DBF_HEX2(0,trace,&delay_target,sizeof(unsigned long));

	result = 0; /* not critical */

out:

	free_page ((unsigned long) scsscf_area);

	mempool_free(scsscf_area, qdio_mempool_scssc);

	return result;

}
@@ -3780,6 +3783,16 @@ oom: 
	return -ENOMEM;

}



static void *qdio_mempool_alloc(gfp_t gfp_mask, void *size)

{

	return (void *) get_zeroed_page(gfp_mask|GFP_DMA);

}



static void qdio_mempool_free(void *element, void *size)

{

	free_page((unsigned long) element);

}



static int __init

init_QDIO(void)

{
@@ -3809,6 +3822,10 @@ init_QDIO(void) 


	qdio_add_procfs_entry();



	qdio_mempool_scssc = mempool_create(QDIO_MEMPOOL_SCSSC_ELEMENTS,

					    qdio_mempool_alloc,

					    qdio_mempool_free, NULL);



	if (tiqdio_check_chsc_availability())

		QDIO_PRINT_ERR("Not all CHSCs supported. Continuing.\n");
@@ -3824,6 +3841,7 @@ cleanup_QDIO(void) 
	qdio_remove_procfs_entry();

	qdio_release_qdio_memory();

	qdio_unregister_dbf_views();

	mempool_destroy(qdio_mempool_scssc);



  	printk("qdio: %s: module removed\n",version);

}