[PATCH 4/5] mm: gup: use get_user_pages_unlocked

[Andrea Arcangeli]

This allows those get_user_pages calls to pass FAULT_FLAG_ALLOW_RETRY
to the page fault in order to release the mmap_sem during the I/O.

Signed-off-by: Andrea Arcangeli <aarca...@redhat.com>
---
 drivers/iommu/amd_iommu_v2.c       | 6 ++----
 drivers/media/pci/ivtv/ivtv-udma.c | 6 ++----
 drivers/scsi/st.c                  | 7 ++-----
 drivers/video/fbdev/pvr2fb.c       | 6 ++----
 mm/process_vm_access.c             | 7 ++-----
 net/ceph/pagevec.c                 | 6 ++----
 6 files changed, 12 insertions(+), 26 deletions(-)

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 90d734b..4cd8a87 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -521,10 +521,8 @@ static void do_fault(struct work_struct *work)
 
        write = !!(fault->flags & PPR_FAULT_WRITE);
 
-       down_read(&fault->state->mm->mmap_sem);
-       npages = get_user_pages(NULL, fault->state->mm,
-                               fault->address, 1, write, 0, &page, NULL);
-       up_read(&fault->state->mm->mmap_sem);
+       npages = get_user_pages_unlocked(NULL, fault->state->mm,
+                                        fault->address, 1, write, 0, &page);
 
        if (npages == 1) {
                put_page(page);
diff --git a/drivers/media/pci/ivtv/ivtv-udma.c 
b/drivers/media/pci/ivtv/ivtv-udma.c
index 7338cb2..96d866b 100644
--- a/drivers/media/pci/ivtv/ivtv-udma.c
+++ b/drivers/media/pci/ivtv/ivtv-udma.c
@@ -124,10 +124,8 @@ int ivtv_udma_setup(struct ivtv *itv, unsigned long 
ivtv_dest_addr,
        }
 
        /* Get user pages for DMA Xfer */
-       down_read(&current->mm->mmap_sem);
-       err = get_user_pages(current, current->mm,
-                       user_dma.uaddr, user_dma.page_count, 0, 1, dma->map, 
NULL);
-       up_read(&current->mm->mmap_sem);
+       err = get_user_pages_unlocked(current, current->mm,
+                       user_dma.uaddr, user_dma.page_count, 0, 1, dma->map);
 
        if (user_dma.page_count != err) {
                IVTV_DEBUG_WARN("failed to map user pages, returned %d instead 
of %d\n",
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 4daa372..a98e00b 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -4538,18 +4538,15 @@ static int sgl_map_user_pages(struct st_buffer *STbp,
                return -ENOMEM;
 
         /* Try to fault in all of the necessary pages */
-       down_read(&current->mm->mmap_sem);
         /* rw==READ means read from drive, write into memory area */
-       res = get_user_pages(
+       res = get_user_pages_unlocked(
                current,
                current->mm,
                uaddr,
                nr_pages,
                rw == READ,
                0, /* don't force */
-               pages,
-               NULL);
-       up_read(&current->mm->mmap_sem);
+               pages);
 
        /* Errors and no page mapped should return here */
        if (res < nr_pages)
diff --git a/drivers/video/fbdev/pvr2fb.c b/drivers/video/fbdev/pvr2fb.c
index 7c74f58..0e24eb9 100644
--- a/drivers/video/fbdev/pvr2fb.c
+++ b/drivers/video/fbdev/pvr2fb.c
@@ -686,10 +686,8 @@ static ssize_t pvr2fb_write(struct fb_info *info, const 
char *buf,
        if (!pages)
                return -ENOMEM;
 
-       down_read(&current->mm->mmap_sem);
-       ret = get_user_pages(current, current->mm, (unsigned long)buf,
-                            nr_pages, WRITE, 0, pages, NULL);
-       up_read(&current->mm->mmap_sem);
+       ret = get_user_pages_unlocked(current, current->mm, (unsigned long)buf,
+                                     nr_pages, WRITE, 0, pages);
 
        if (ret < nr_pages) {
                nr_pages = ret;
diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 5077afc..b159769 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -99,11 +99,8 @@ static int process_vm_rw_single_vec(unsigned long addr,
                size_t bytes;
 
                /* Get the pages we're interested in */
-               down_read(&mm->mmap_sem);
-               pages = get_user_pages(task, mm, pa, pages,
-                                     vm_write, 0, process_pages, NULL);
-               up_read(&mm->mmap_sem);
-
+               pages = get_user_pages_unlocked(task, mm, pa, pages,
+                                               vm_write, 0, process_pages);
                if (pages <= 0)
                        return -EFAULT;
 
diff --git a/net/ceph/pagevec.c b/net/ceph/pagevec.c
index 5550130..096d914 100644
--- a/net/ceph/pagevec.c
+++ b/net/ceph/pagevec.c
@@ -23,17 +23,15 @@ struct page **ceph_get_direct_page_vector(const void __user 
*data,
        if (!pages)
                return ERR_PTR(-ENOMEM);
 
-       down_read(&current->mm->mmap_sem);
        while (got < num_pages) {
-               rc = get_user_pages(current, current->mm,
+               rc = get_user_pages_unlocked(current, current->mm,
                    (unsigned long)data + ((unsigned long)got * PAGE_SIZE),
-                   num_pages - got, write_page, 0, pages + got, NULL);
+                   num_pages - got, write_page, 0, pages + got);
                if (rc < 0)
                        break;
                BUG_ON(rc == 0);
                got += rc;
        }
-       up_read(&current->mm->mmap_sem);
        if (rc < 0)
                goto fail;
        return pages;
--
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