Re: [PATCH 07/19] infiniband: set FOLL_PIN, FOLL_LONGTERM via pin_longterm_pages*()

From: John Hubbard
Date: Thu Oct 31 2019 - 19:49:20 EST

On 10/31/19 4:25 PM, Ira Weiny wrote:
> On Wed, Oct 30, 2019 at 03:49:18PM -0700, John Hubbard wrote:
>> Convert infiniband to use the new wrapper calls, and stop
>> explicitly setting FOLL_LONGTERM at the call sites.
>>
>> The new pin_longterm_*() calls replace get_user_pages*()
>> calls, and set both FOLL_LONGTERM and a new FOLL_PIN
>> flag. The FOLL_PIN flag requires that the caller must
>> return the pages via put_user_page*() calls, but
>> infiniband was already doing that as part of an earlier
>> commit.
>>
>
> NOTE: I'm not 100% convinced that mixing the flags and new calls like this is
> good. I think we are going to need a lot more documentation on which flags are
> "user" accessible vs not...

I'm open to suggestion there. I'm too close to it now to see what's missing,
though...maybe after you take a peek at Documentation/ let's see if it's
still the case...


thanks,

John Hubbard
NVIDIA

>
> Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
>
>> Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
>> ---
>> drivers/infiniband/core/umem.c | 5 ++---
>> drivers/infiniband/core/umem_odp.c | 10 +++++-----
>> drivers/infiniband/hw/hfi1/user_pages.c | 4 ++--
>> drivers/infiniband/hw/mthca/mthca_memfree.c | 3 +--
>> drivers/infiniband/hw/qib/qib_user_pages.c | 8 ++++----
>> drivers/infiniband/hw/qib/qib_user_sdma.c | 2 +-
>> drivers/infiniband/hw/usnic/usnic_uiom.c | 9 ++++-----
>> drivers/infiniband/sw/siw/siw_mem.c | 5 ++---
>> 8 files changed, 21 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
>> index 24244a2f68cc..c5a78d3e674b 100644
>> --- a/drivers/infiniband/core/umem.c
>> +++ b/drivers/infiniband/core/umem.c
>> @@ -272,11 +272,10 @@ struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr,
>>
>> while (npages) {
>> down_read(&mm->mmap_sem);
>> - ret = get_user_pages(cur_base,
>> + ret = pin_longterm_pages(cur_base,
>> min_t(unsigned long, npages,
>> PAGE_SIZE / sizeof (struct page *)),
>> - gup_flags | FOLL_LONGTERM,
>> - page_list, NULL);
>> + gup_flags, page_list, NULL);
>> if (ret < 0) {
>> up_read(&mm->mmap_sem);
>> goto umem_release;
>> diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
>> index 163ff7ba92b7..a38b67b83db5 100644
>> --- a/drivers/infiniband/core/umem_odp.c
>> +++ b/drivers/infiniband/core/umem_odp.c
>> @@ -534,7 +534,7 @@ static int ib_umem_odp_map_dma_single_page(
>> } else if (umem_odp->page_list[page_index] == page) {
>> umem_odp->dma_list[page_index] |= access_mask;
>> } else {
>> - pr_err("error: got different pages in IB device and from get_user_pages. IB device page: %p, gup page: %p\n",
>> + pr_err("error: got different pages in IB device and from pin_longterm_pages. IB device page: %p, gup page: %p\n",
>> umem_odp->page_list[page_index], page);
>> /* Better remove the mapping now, to prevent any further
>> * damage. */
>> @@ -639,11 +639,11 @@ int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt,
>> /*
>> * Note: this might result in redundent page getting. We can
>> * avoid this by checking dma_list to be 0 before calling
>> - * get_user_pages. However, this make the code much more
>> - * complex (and doesn't gain us much performance in most use
>> - * cases).
>> + * pin_longterm_pages. However, this makes the code much
>> + * more complex (and doesn't gain us much performance in most
>> + * use cases).
>> */
>> - npages = get_user_pages_remote(owning_process, owning_mm,
>> + npages = pin_longterm_pages_remote(owning_process, owning_mm,
>> user_virt, gup_num_pages,
>> flags, local_page_list, NULL, NULL);
>> up_read(&owning_mm->mmap_sem);
>> diff --git a/drivers/infiniband/hw/hfi1/user_pages.c b/drivers/infiniband/hw/hfi1/user_pages.c
>> index 469acb961fbd..9b55b0a73e29 100644
>> --- a/drivers/infiniband/hw/hfi1/user_pages.c
>> +++ b/drivers/infiniband/hw/hfi1/user_pages.c
>> @@ -104,9 +104,9 @@ int hfi1_acquire_user_pages(struct mm_struct *mm, unsigned long vaddr, size_t np
>> bool writable, struct page **pages)
>> {
>> int ret;
>> - unsigned int gup_flags = FOLL_LONGTERM | (writable ? FOLL_WRITE : 0);
>> + unsigned int gup_flags = (writable ? FOLL_WRITE : 0);
>>
>> - ret = get_user_pages_fast(vaddr, npages, gup_flags, pages);
>> + ret = pin_longterm_pages_fast(vaddr, npages, gup_flags, pages);
>> if (ret < 0)
>> return ret;
>>
>> diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c
>> index edccfd6e178f..beec7e4b8a96 100644
>> --- a/drivers/infiniband/hw/mthca/mthca_memfree.c
>> +++ b/drivers/infiniband/hw/mthca/mthca_memfree.c
>> @@ -472,8 +472,7 @@ int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
>> goto out;
>> }
>>
>> - ret = get_user_pages_fast(uaddr & PAGE_MASK, 1,
>> - FOLL_WRITE | FOLL_LONGTERM, pages);
>> + ret = pin_longterm_pages_fast(uaddr & PAGE_MASK, 1, FOLL_WRITE, pages);
>> if (ret < 0)
>> goto out;
>>
>> diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c
>> index 6bf764e41891..684a14e14d9b 100644
>> --- a/drivers/infiniband/hw/qib/qib_user_pages.c
>> +++ b/drivers/infiniband/hw/qib/qib_user_pages.c
>> @@ -108,10 +108,10 @@ int qib_get_user_pages(unsigned long start_page, size_t num_pages,
>>
>> down_read(&current->mm->mmap_sem);
>> for (got = 0; got < num_pages; got += ret) {
>> - ret = get_user_pages(start_page + got * PAGE_SIZE,
>> - num_pages - got,
>> - FOLL_LONGTERM | FOLL_WRITE | FOLL_FORCE,
>> - p + got, NULL);
>> + ret = pin_longterm_pages(start_page + got * PAGE_SIZE,
>> + num_pages - got,
>> + FOLL_WRITE | FOLL_FORCE,
>> + p + got, NULL);
>> if (ret < 0) {
>> up_read(&current->mm->mmap_sem);
>> goto bail_release;
>> diff --git a/drivers/infiniband/hw/qib/qib_user_sdma.c b/drivers/infiniband/hw/qib/qib_user_sdma.c
>> index 05190edc2611..fd86a9d19370 100644
>> --- a/drivers/infiniband/hw/qib/qib_user_sdma.c
>> +++ b/drivers/infiniband/hw/qib/qib_user_sdma.c
>> @@ -670,7 +670,7 @@ static int qib_user_sdma_pin_pages(const struct qib_devdata *dd,
>> else
>> j = npages;
>>
>> - ret = get_user_pages_fast(addr, j, FOLL_LONGTERM, pages);
>> + ret = pin_longterm_pages_fast(addr, j, 0, pages);
>> if (ret != j) {
>> i = 0;
>> j = ret;
>> diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c
>> index 62e6ffa9ad78..6b90ca1c3771 100644
>> --- a/drivers/infiniband/hw/usnic/usnic_uiom.c
>> +++ b/drivers/infiniband/hw/usnic/usnic_uiom.c
>> @@ -141,11 +141,10 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable,
>> ret = 0;
>>
>> while (npages) {
>> - ret = get_user_pages(cur_base,
>> - min_t(unsigned long, npages,
>> - PAGE_SIZE / sizeof(struct page *)),
>> - gup_flags | FOLL_LONGTERM,
>> - page_list, NULL);
>> + ret = pin_longterm_pages(cur_base,
>> + min_t(unsigned long, npages,
>> + PAGE_SIZE / sizeof(struct page *)),
>> + gup_flags, page_list, NULL);
>>
>> if (ret < 0)
>> goto out;
>> diff --git a/drivers/infiniband/sw/siw/siw_mem.c b/drivers/infiniband/sw/siw/siw_mem.c
>> index e99983f07663..20e663d7ada8 100644
>> --- a/drivers/infiniband/sw/siw/siw_mem.c
>> +++ b/drivers/infiniband/sw/siw/siw_mem.c
>> @@ -426,9 +426,8 @@ struct siw_umem *siw_umem_get(u64 start, u64 len, bool writable)
>> while (nents) {
>> struct page **plist = &umem->page_chunk[i].plist[got];
>>
>> - rv = get_user_pages(first_page_va, nents,
>> - foll_flags | FOLL_LONGTERM,
>> - plist, NULL);
>> + rv = pin_longterm_pages(first_page_va, nents,
>> + foll_flags, plist, NULL);
>> if (rv < 0)
>> goto out_sem_up;
>>
>> --
>> 2.23.0
>>