In this 3rd version of the patch series, I have compressed the patches
of the previous patch series into one patch. This was suggested by Christoph Hellwig.
The suggestion was to remove the pte_lookup functions and use the g
et_user_pages* functions directly instead of the pte_lookup functions.
There is nothing different in this series compared to the previous
series, It essentially compresses the 3 patches of the original series
into one patch.
Bharath Vedartham (1):
sgi-gru: Remove *pte_lookup functions
drivers/misc/sgi-gru/grufault.c | 114 +++++++++-------------------------------
1 file changed, 25 insertions(+), 89 deletions(-)
--
2.7.4
The *pte_lookup functions can be removed and be easily replaced with
get_user_pages_fast functions. In the case of atomic lookup,
__get_user_pages_fast is used which does not fall back to slow
get_user_pages. get_user_pages_fast on the other hand tries to use
__get_user_pages_fast but fallbacks to slow get_user_pages if
__get_user_pages_fast fails.
Also unnecessary ifdefs to check for CONFIG_HUGETLB is removed as the
check is redundant.
Cc: Ira Weiny <[email protected]>
Cc: John Hubbard <[email protected]>
Cc: Jérôme Glisse <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Dimitri Sivanich <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: William Kucharski <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: [email protected]
Cc: [email protected]
Reviewed-by: Ira Weiny <[email protected]>
Reviewed-by: John Hubbard <[email protected]>
Reviewed-by: William Kucharski <[email protected]>
Signed-off-by: Bharath Vedartham <[email protected]>
---
This is a fold of the 3 patches in the previous patch series.
The review tags were given to the individual patches.
---
drivers/misc/sgi-gru/grufault.c | 114 +++++++++-------------------------------
1 file changed, 25 insertions(+), 89 deletions(-)
diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index 4b713a8..c1258ea 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -166,96 +166,20 @@ static void get_clear_fault_map(struct gru_state *gru,
}
/*
- * Atomic (interrupt context) & non-atomic (user context) functions to
- * convert a vaddr into a physical address. The size of the page
- * is returned in pageshift.
- * returns:
- * 0 - successful
- * < 0 - error code
- * 1 - (atomic only) try again in non-atomic context
- */
-static int non_atomic_pte_lookup(struct vm_area_struct *vma,
- unsigned long vaddr, int write,
- unsigned long *paddr, int *pageshift)
-{
- struct page *page;
-
-#ifdef CONFIG_HUGETLB_PAGE
- *pageshift = is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : PAGE_SHIFT;
-#else
- *pageshift = PAGE_SHIFT;
-#endif
- if (get_user_pages(vaddr, 1, write ? FOLL_WRITE : 0, &page, NULL) <= 0)
- return -EFAULT;
- *paddr = page_to_phys(page);
- put_page(page);
- return 0;
-}
-
-/*
- * atomic_pte_lookup
+ * mmap_sem is already helod on entry to this function. This guarantees
+ * existence of the page tables.
*
- * Convert a user virtual address to a physical address
* Only supports Intel large pages (2MB only) on x86_64.
- * ZZZ - hugepage support is incomplete
- *
- * NOTE: mmap_sem is already held on entry to this function. This
- * guarantees existence of the page tables.
+ * ZZZ - hugepage support is incomplete.
*/
-static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned long vaddr,
- int write, unsigned long *paddr, int *pageshift)
-{
- pgd_t *pgdp;
- p4d_t *p4dp;
- pud_t *pudp;
- pmd_t *pmdp;
- pte_t pte;
-
- pgdp = pgd_offset(vma->vm_mm, vaddr);
- if (unlikely(pgd_none(*pgdp)))
- goto err;
-
- p4dp = p4d_offset(pgdp, vaddr);
- if (unlikely(p4d_none(*p4dp)))
- goto err;
-
- pudp = pud_offset(p4dp, vaddr);
- if (unlikely(pud_none(*pudp)))
- goto err;
-
- pmdp = pmd_offset(pudp, vaddr);
- if (unlikely(pmd_none(*pmdp)))
- goto err;
-#ifdef CONFIG_X86_64
- if (unlikely(pmd_large(*pmdp)))
- pte = *(pte_t *) pmdp;
- else
-#endif
- pte = *pte_offset_kernel(pmdp, vaddr);
-
- if (unlikely(!pte_present(pte) ||
- (write && (!pte_write(pte) || !pte_dirty(pte)))))
- return 1;
-
- *paddr = pte_pfn(pte) << PAGE_SHIFT;
-#ifdef CONFIG_HUGETLB_PAGE
- *pageshift = is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : PAGE_SHIFT;
-#else
- *pageshift = PAGE_SHIFT;
-#endif
- return 0;
-
-err:
- return 1;
-}
-
static int gru_vtop(struct gru_thread_state *gts, unsigned long vaddr,
int write, int atomic, unsigned long *gpa, int *pageshift)
{
struct mm_struct *mm = gts->ts_mm;
struct vm_area_struct *vma;
unsigned long paddr;
- int ret, ps;
+ int ret;
+ struct page *page;
vma = find_vma(mm, vaddr);
if (!vma)
@@ -263,21 +187,33 @@ static int gru_vtop(struct gru_thread_state *gts, unsigned long vaddr,
/*
* Atomic lookup is faster & usually works even if called in non-atomic
- * context.
+ * context. get_user_pages_fast does atomic lookup before falling back to
+ * slow gup.
*/
rmb(); /* Must/check ms_range_active before loading PTEs */
- ret = atomic_pte_lookup(vma, vaddr, write, &paddr, &ps);
- if (ret) {
- if (atomic)
+ if (atomic) {
+ ret = __get_user_pages_fast(vaddr, 1, write, &page);
+ if (!ret)
goto upm;
- if (non_atomic_pte_lookup(vma, vaddr, write, &paddr, &ps))
+ } else {
+ ret = get_user_pages_fast(vaddr, 1, write, &page);
+ if (!ret)
goto inval;
}
+
+ paddr = page_to_phys(page);
+ put_user_page(page);
+
+ if (unlikely(is_vm_hugetlb_page(vma)))
+ *pageshift = HPAGE_SHIFT;
+ else
+ *pageshift = PAGE_SHIFT;
+
if (is_gru_paddr(paddr))
goto inval;
- paddr = paddr & ~((1UL << ps) - 1);
- *gpa = uv_soc_phys_ram_to_gpa(paddr);
- *pageshift = ps;
+ paddr = paddr & ~((1UL << *pageshift) - 1);
+ *gpa = uv_soc_phys_ram_to_gpa(paddr);
+
return VTOP_SUCCESS;
inval:
--
2.7.4
On Sat, Jul 27, 2019 at 05:22:28PM +0800, Hillf Danton wrote:
>
> On Fri, 26 Jul 2019 12:42:26 -0700 (PDT) Bharath Vedartham wrote:
> >
> > static int gru_vtop(struct gru_thread_state *gts, unsigned long vaddr,
> > int write, int atomic, unsigned long *gpa, int *pageshift)
> > {
> > struct mm_struct *mm = gts->ts_mm;
> > struct vm_area_struct *vma;
> > unsigned long paddr;
> > - int ret, ps;
> > + int ret;
> > + struct page *page;
> >
> > vma = find_vma(mm, vaddr);
> > if (!vma)
> > @@ -263,21 +187,33 @@ static int gru_vtop(struct gru_thread_state *gts, unsigned long vaddr,
> >
> > /*
> > * Atomic lookup is faster & usually works even if called in non-atomic
> > - * context.
> > + * context. get_user_pages_fast does atomic lookup before falling back to
> > + * slow gup.
> > */
> > rmb(); /* Must/check ms_range_active before loading PTEs */
> > - ret = atomic_pte_lookup(vma, vaddr, write, &paddr, &ps);
> > - if (ret) {
> > - if (atomic)
> > + if (atomic) {
> > + ret = __get_user_pages_fast(vaddr, 1, write, &page);
> > + if (!ret)
> > goto upm;
> > - if (non_atomic_pte_lookup(vma, vaddr, write, &paddr, &ps))
> > + } else {
> > + ret = get_user_pages_fast(vaddr, 1, write, &page);
> > + if (!ret)
> > goto inval;
> > }
> > +
> > + paddr = page_to_phys(page);
>
> You may drop find_vma() above if PageHuge(page) makes sense here.
I don't think it does. Hugepage support is still incomplete for this
driver.
Thank you
Bharath
> > + put_user_page(page);
> > +
> > + if (unlikely(is_vm_hugetlb_page(vma)))
> > + *pageshift = HPAGE_SHIFT;
> > + else
> > + *pageshift = PAGE_SHIFT;
> > +
> > if (is_gru_paddr(paddr))
> > goto inval;
> > - paddr = paddr & ~((1UL << ps) - 1);
> > - *gpa = uv_soc_phys_ram_to_gpa(paddr);
> > - *pageshift = ps;
> > + paddr = paddr & ~((1UL << *pageshift) - 1);
> > + *gpa = uv_soc_phys_ram_to_gpa(paddr);
> > +
> > return VTOP_SUCCESS;
> >
> > inval:
> > --
> > 2.7.4
>
On Sat, Jul 27, 2019 at 01:12:00AM +0530, Bharath Vedartham wrote:
> + ret = get_user_pages_fast(vaddr, 1, write, &page);
I think you want to pass "write ? FOLL_WRITE : 0" here, as
get_user_pages_fast takes a gup_flags argument, not a boolean
write flag.
On Mon, Jul 29, 2019 at 08:48:42AM +0200, Christoph Hellwig wrote:
> On Sat, Jul 27, 2019 at 01:12:00AM +0530, Bharath Vedartham wrote:
> > + ret = get_user_pages_fast(vaddr, 1, write, &page);
>
> I think you want to pass "write ? FOLL_WRITE : 0" here, as
> get_user_pages_fast takes a gup_flags argument, not a boolean
> write flag.
You are right there! I ll send another version correcting this.
Thank you
Bharath