On Thu, Oct 20, 2016 at 02:03:48PM +1100, Alexey Kardashevskiy wrote:
> This changes mm_iommu_xxx helpers to take mm_struct as a parameter
> instead of getting it from @current which in some situations may
> not have a valid reference to mm.
>
> This changes helpers to receive @mm and moves all references to @current
> to the caller, including checks for !current and !current->mm;
> checks in mm_iommu_preregistered() are removed as there is no caller
> yet.
>
> This moves the mm_iommu_adjust_locked_vm() call to the caller as
> it receives mm_iommu_table_group_mem_t but it needs mm.
>
> This should cause no behavioral change.
>
> Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
Reviewed-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> ---
> arch/powerpc/include/asm/mmu_context.h | 16 ++++++------
> arch/powerpc/mm/mmu_context_iommu.c | 46 +++++++++++++---------------------
> drivers/vfio/vfio_iommu_spapr_tce.c | 14 ++++++++---
> 3 files changed, 36 insertions(+), 40 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
> index 424844b..b9e3f0a 100644
> --- a/arch/powerpc/include/asm/mmu_context.h
> +++ b/arch/powerpc/include/asm/mmu_context.h
> @@ -19,16 +19,18 @@ extern void destroy_context(struct mm_struct *mm);
> struct mm_iommu_table_group_mem_t;
>
> extern int isolate_lru_page(struct page *page); /* from internal.h */
> -extern bool mm_iommu_preregistered(void);
> -extern long mm_iommu_get(unsigned long ua, unsigned long entries,
> +extern bool mm_iommu_preregistered(struct mm_struct *mm);
> +extern long mm_iommu_get(struct mm_struct *mm,
> + unsigned long ua, unsigned long entries,
> struct mm_iommu_table_group_mem_t **pmem);
> -extern long mm_iommu_put(struct mm_iommu_table_group_mem_t *mem);
> +extern long mm_iommu_put(struct mm_struct *mm,
> + struct mm_iommu_table_group_mem_t *mem);
> extern void mm_iommu_init(struct mm_struct *mm);
> extern void mm_iommu_cleanup(struct mm_struct *mm);
> -extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup(unsigned long ua,
> - unsigned long size);
> -extern struct mm_iommu_table_group_mem_t *mm_iommu_find(unsigned long ua,
> - unsigned long entries);
> +extern struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm,
> + unsigned long ua, unsigned long size);
> +extern struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
> + unsigned long ua, unsigned long entries);
> extern long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem,
> unsigned long ua, unsigned long *hpa);
> extern long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem);
> diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c
> index ad2e575..4c6db09 100644
> --- a/arch/powerpc/mm/mmu_context_iommu.c
> +++ b/arch/powerpc/mm/mmu_context_iommu.c
> @@ -56,7 +56,7 @@ static long mm_iommu_adjust_locked_vm(struct mm_struct *mm,
> }
>
> pr_debug("[%d] RLIMIT_MEMLOCK HASH64 %c%ld %ld/%ld\n",
> - current->pid,
> + current ? current->pid : 0,
> incr ? '+' : '-',
> npages << PAGE_SHIFT,
> mm->locked_vm << PAGE_SHIFT,
> @@ -66,12 +66,9 @@ static long mm_iommu_adjust_locked_vm(struct mm_struct *mm,
> return ret;
> }
>
> -bool mm_iommu_preregistered(void)
> +bool mm_iommu_preregistered(struct mm_struct *mm)
> {
> - if (!current || !current->mm)
> - return false;
> -
> - return !list_empty(¤t->mm->context.iommu_group_mem_list);
> + return !list_empty(&mm->context.iommu_group_mem_list);
> }
> EXPORT_SYMBOL_GPL(mm_iommu_preregistered);
>
> @@ -124,19 +121,16 @@ static int mm_iommu_move_page_from_cma(struct page *page)
> return 0;
> }
>
> -long mm_iommu_get(unsigned long ua, unsigned long entries,
> +long mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long entries,
> struct mm_iommu_table_group_mem_t **pmem)
> {
> struct mm_iommu_table_group_mem_t *mem;
> long i, j, ret = 0, locked_entries = 0;
> struct page *page = NULL;
>
> - if (!current || !current->mm)
> - return -ESRCH; /* process exited */
> -
> mutex_lock(&mem_list_mutex);
>
> - list_for_each_entry_rcu(mem, ¤t->mm->context.iommu_group_mem_list,
> + list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list,
> next) {
> if ((mem->ua == ua) && (mem->entries == entries)) {
> ++mem->used;
> @@ -154,7 +148,7 @@ long mm_iommu_get(unsigned long ua, unsigned long entries,
>
> }
>
> - ret = mm_iommu_adjust_locked_vm(current->mm, entries, true);
> + ret = mm_iommu_adjust_locked_vm(mm, entries, true);
> if (ret)
> goto unlock_exit;
>
> @@ -215,11 +209,11 @@ long mm_iommu_get(unsigned long ua, unsigned long entries,
> mem->entries = entries;
> *pmem = mem;
>
> - list_add_rcu(&mem->next, ¤t->mm->context.iommu_group_mem_list);
> + list_add_rcu(&mem->next, &mm->context.iommu_group_mem_list);
>
> unlock_exit:
> if (locked_entries && ret)
> - mm_iommu_adjust_locked_vm(current->mm, locked_entries, false);
> + mm_iommu_adjust_locked_vm(mm, locked_entries, false);
>
> mutex_unlock(&mem_list_mutex);
>
> @@ -264,17 +258,13 @@ static void mm_iommu_free(struct rcu_head *head)
> static void mm_iommu_release(struct mm_iommu_table_group_mem_t *mem)
> {
> list_del_rcu(&mem->next);
> - mm_iommu_adjust_locked_vm(current->mm, mem->entries, false);
> call_rcu(&mem->rcu, mm_iommu_free);
> }
>
> -long mm_iommu_put(struct mm_iommu_table_group_mem_t *mem)
> +long mm_iommu_put(struct mm_struct *mm, struct mm_iommu_table_group_mem_t *mem)
> {
> long ret = 0;
>
> - if (!current || !current->mm)
> - return -ESRCH; /* process exited */
> -
> mutex_lock(&mem_list_mutex);
>
> if (mem->used == 0) {
> @@ -297,6 +287,8 @@ long mm_iommu_put(struct mm_iommu_table_group_mem_t *mem)
> /* @mapped became 0 so now mappings are disabled, release the region */
> mm_iommu_release(mem);
>
> + mm_iommu_adjust_locked_vm(mm, mem->entries, false);
> +
> unlock_exit:
> mutex_unlock(&mem_list_mutex);
>
> @@ -304,14 +296,12 @@ long mm_iommu_put(struct mm_iommu_table_group_mem_t *mem)
> }
> EXPORT_SYMBOL_GPL(mm_iommu_put);
>
> -struct mm_iommu_table_group_mem_t *mm_iommu_lookup(unsigned long ua,
> - unsigned long size)
> +struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm,
> + unsigned long ua, unsigned long size)
> {
> struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
>
> - list_for_each_entry_rcu(mem,
> - ¤t->mm->context.iommu_group_mem_list,
> - next) {
> + list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) {
> if ((mem->ua <= ua) &&
> (ua + size <= mem->ua +
> (mem->entries << PAGE_SHIFT))) {
> @@ -324,14 +314,12 @@ struct mm_iommu_table_group_mem_t *mm_iommu_lookup(unsigned long ua,
> }
> EXPORT_SYMBOL_GPL(mm_iommu_lookup);
>
> -struct mm_iommu_table_group_mem_t *mm_iommu_find(unsigned long ua,
> - unsigned long entries)
> +struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm,
> + unsigned long ua, unsigned long entries)
> {
> struct mm_iommu_table_group_mem_t *mem, *ret = NULL;
>
> - list_for_each_entry_rcu(mem,
> - ¤t->mm->context.iommu_group_mem_list,
> - next) {
> + list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) {
> if ((mem->ua == ua) && (mem->entries == entries)) {
> ret = mem;
> break;
> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
> index 80378dd..d0c38b2 100644
> --- a/drivers/vfio/vfio_iommu_spapr_tce.c
> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c
> @@ -107,14 +107,17 @@ static long tce_iommu_unregister_pages(struct tce_container *container,
> {
> struct mm_iommu_table_group_mem_t *mem;
>
> + if (!current || !current->mm)
> + return -ESRCH; /* process exited */
> +
> if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK))
> return -EINVAL;
>
> - mem = mm_iommu_find(vaddr, size >> PAGE_SHIFT);
> + mem = mm_iommu_find(current->mm, vaddr, size >> PAGE_SHIFT);
> if (!mem)
> return -ENOENT;
>
> - return mm_iommu_put(mem);
> + return mm_iommu_put(current->mm, mem);
> }
>
> static long tce_iommu_register_pages(struct tce_container *container,
> @@ -124,11 +127,14 @@ static long tce_iommu_register_pages(struct tce_container *container,
> struct mm_iommu_table_group_mem_t *mem = NULL;
> unsigned long entries = size >> PAGE_SHIFT;
>
> + if (!current || !current->mm)
> + return -ESRCH; /* process exited */
> +
> if ((vaddr & ~PAGE_MASK) || (size & ~PAGE_MASK) ||
> ((vaddr + size) < vaddr))
> return -EINVAL;
>
> - ret = mm_iommu_get(vaddr, entries, &mem);
> + ret = mm_iommu_get(current->mm, vaddr, entries, &mem);
> if (ret)
> return ret;
>
> @@ -375,7 +381,7 @@ static int tce_iommu_prereg_ua_to_hpa(unsigned long tce, unsigned long size,
> long ret = 0;
> struct mm_iommu_table_group_mem_t *mem;
>
> - mem = mm_iommu_lookup(tce, size);
> + mem = mm_iommu_lookup(current->mm, tce, size);
> if (!mem)
> return -EINVAL;
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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