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Commit 7f2251b1 authored by Jack Steiner's avatar Jack Steiner Committed by Linus Torvalds
Browse files

gru: handle failures to mmu_notifier_register 



Under some conditions, mmu_notifier_register() will fail to register a
mmu_notifier.  Fix the GRU driver to correctly handle these failures.

Signed-off-by: default avatarJack Steiner <steiner@sgi.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6c9620c6

drivers/misc/sgi-gru/grufault.c

+3 −3
Original line number Diff line number Diff line
@@ -96,7 +96,7 @@ static struct gru_thread_state *gru_alloc_locked_gts(unsigned long vaddr) 
	vma = gru_find_vma(vaddr);

	if (vma)

		gts = gru_alloc_thread_state(vma, TSID(vaddr, vma));

	if (gts) {

	if (!IS_ERR(gts)) {

		mutex_lock(&gts->ts_ctxlock);

		downgrade_write(&mm->mmap_sem);

	} else {
@@ -747,8 +747,8 @@ int gru_set_context_option(unsigned long arg) 
	gru_dbg(grudev, "op %d, gseg 0x%lx, value1 0x%lx\n", req.op, req.gseg, req.val1);



	gts = gru_alloc_locked_gts(req.gseg);

	if (!gts)

		return -EINVAL;

	if (IS_ERR(gts))

		return PTR_ERR(gts);



	switch (req.op) {

	case sco_blade_chiplet:

drivers/misc/sgi-gru/grumain.c

+11 −7
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/sched.h>

#include <linux/device.h>

#include <linux/list.h>

#include <linux/err.h>

#include <asm/uv/uv_hub.h>

#include "gru.h"

#include "grutables.h"
@@ -286,6 +287,7 @@ static void gru_unload_mm_tracker(struct gru_state *gru, 
void gts_drop(struct gru_thread_state *gts)

{

	if (gts && atomic_dec_return(&gts->ts_refcnt) == 0) {

		if (gts->ts_gms)

			gru_drop_mmu_notifier(gts->ts_gms);

		kfree(gts);

		STAT(gts_free);
@@ -313,13 +315,14 @@ struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma, 
		int cbr_au_count, int dsr_au_count, int options, int tsid)

{

	struct gru_thread_state *gts;

	struct gru_mm_struct *gms;

	int bytes;



	bytes = DSR_BYTES(dsr_au_count) + CBR_BYTES(cbr_au_count);

	bytes += sizeof(struct gru_thread_state);

	gts = kmalloc(bytes, GFP_KERNEL);

	if (!gts)

		return NULL;

		return ERR_PTR(-ENOMEM);



	STAT(gts_alloc);

	memset(gts, 0, sizeof(struct gru_thread_state)); /* zero out header */
@@ -338,9 +341,10 @@ struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma, 
	if (vma) {

		gts->ts_mm = current->mm;

		gts->ts_vma = vma;

		gts->ts_gms = gru_register_mmu_notifier();

		if (!gts->ts_gms)

		gms = gru_register_mmu_notifier();

		if (IS_ERR(gms))

			goto err;

		gts->ts_gms = gms;

	}



	gru_dbg(grudev, "alloc gts %p\n", gts);
@@ -348,7 +352,7 @@ struct gru_thread_state *gru_alloc_gts(struct vm_area_struct *vma, 


err:

	gts_drop(gts);

	return NULL;

	return ERR_CAST(gms);

}



/*
@@ -396,8 +400,8 @@ struct gru_thread_state *gru_alloc_thread_state(struct vm_area_struct *vma, 


	gts = gru_alloc_gts(vma, vdata->vd_cbr_au_count, vdata->vd_dsr_au_count,

			    vdata->vd_user_options, tsid);

	if (!gts)

		return NULL;

	if (IS_ERR(gts))

		return gts;



	spin_lock(&vdata->vd_lock);

	ngts = gru_find_current_gts_nolock(vdata, tsid);

drivers/misc/sgi-gru/grutlbpurge.c

+7 −1
Original line number Diff line number Diff line
@@ -299,6 +299,7 @@ struct gru_mm_struct *gru_register_mmu_notifier(void) 
{

	struct gru_mm_struct *gms;

	struct mmu_notifier *mn;

	int err;



	mn = mmu_find_ops(current->mm, &gru_mmuops);

	if (mn) {
@@ -311,12 +312,17 @@ struct gru_mm_struct *gru_register_mmu_notifier(void) 
			gms->ms_notifier.ops = &gru_mmuops;

			atomic_set(&gms->ms_refcnt, 1);

			init_waitqueue_head(&gms->ms_wait_queue);

			__mmu_notifier_register(&gms->ms_notifier, current->mm);

			err = __mmu_notifier_register(&gms->ms_notifier, current->mm);

			if (err)

				goto error;

		}

	}

	gru_dbg(grudev, "gms %p, refcnt %d\n", gms,

		atomic_read(&gms->ms_refcnt));

	return gms;

error:

	kfree(gms);

	return ERR_PTR(err);

}



void gru_drop_mmu_notifier(struct gru_mm_struct *gms)