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Subject[PATCH 21/26] ib: Convert ipath_get_user_pages() to get_user_pages_unlocked()
Date
Convert ipath_get_user_pages() to use get_user_pages_unlocked(). This
shortens the section where we hold mmap_sem for writing and also removes
the knowledge about get_user_pages() locking from ipath driver. We also
fix a bug in testing pinned number of pages when changing the code.

CC: Mike Marciniszyn <infinipath@intel.com>
CC: Roland Dreier <roland@kernel.org>
CC: linux-rdma@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
---
drivers/infiniband/hw/ipath/ipath_user_pages.c | 62 +++++++++++---------------
1 file changed, 27 insertions(+), 35 deletions(-)

diff --git a/drivers/infiniband/hw/ipath/ipath_user_pages.c b/drivers/infiniband/hw/ipath/ipath_user_pages.c
index dc66c4506916..a89af9654112 100644
--- a/drivers/infiniband/hw/ipath/ipath_user_pages.c
+++ b/drivers/infiniband/hw/ipath/ipath_user_pages.c
@@ -52,40 +52,58 @@ static void __ipath_release_user_pages(struct page **p, size_t num_pages,
}
}

-/* call with current->mm->mmap_sem held */
-static int __ipath_get_user_pages(unsigned long start_page, size_t num_pages,
- struct page **p, struct vm_area_struct **vma)
+/**
+ * ipath_get_user_pages - lock user pages into memory
+ * @start_page: the start page
+ * @num_pages: the number of pages
+ * @p: the output page structures
+ *
+ * This function takes a given start page (page aligned user virtual
+ * address) and pins it and the following specified number of pages. For
+ * now, num_pages is always 1, but that will probably change at some point
+ * (because caller is doing expected sends on a single virtually contiguous
+ * buffer, so we can do all pages at once).
+ */
+int ipath_get_user_pages(unsigned long start_page, size_t num_pages,
+ struct page **p)
{
unsigned long lock_limit;
size_t got;
int ret;

+ down_write(&current->mm->mmap_sem);
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;

- if (num_pages > lock_limit) {
+ if (current->mm->pinned_vm + num_pages > lock_limit &&
+ !capable(CAP_IPC_LOCK)) {
+ up_write(&current->mm->mmap_sem);
ret = -ENOMEM;
goto bail;
}
+ current->mm->pinned_vm += num_pages;
+ up_write(&current->mm->mmap_sem);

ipath_cdbg(VERBOSE, "pin %lx pages from vaddr %lx\n",
(unsigned long) num_pages, start_page);

for (got = 0; got < num_pages; got += ret) {
- ret = get_user_pages(current, current->mm,
- start_page + got * PAGE_SIZE,
- num_pages - got, 1, 1,
- p + got, vma);
+ ret = get_user_pages_unlocked(current, current->mm,
+ start_page + got * PAGE_SIZE,
+ num_pages - got, 1, 1,
+ p + got);
if (ret < 0)
goto bail_release;
}

- current->mm->pinned_vm += num_pages;

ret = 0;
goto bail;

bail_release:
__ipath_release_user_pages(p, got, 0);
+ down_write(&current->mm->mmap_sem);
+ current->mm->pinned_vm -= num_pages;
+ up_write(&current->mm->mmap_sem);
bail:
return ret;
}
@@ -146,32 +164,6 @@ dma_addr_t ipath_map_single(struct pci_dev *hwdev, void *ptr, size_t size,
return phys;
}

-/**
- * ipath_get_user_pages - lock user pages into memory
- * @start_page: the start page
- * @num_pages: the number of pages
- * @p: the output page structures
- *
- * This function takes a given start page (page aligned user virtual
- * address) and pins it and the following specified number of pages. For
- * now, num_pages is always 1, but that will probably change at some point
- * (because caller is doing expected sends on a single virtually contiguous
- * buffer, so we can do all pages at once).
- */
-int ipath_get_user_pages(unsigned long start_page, size_t num_pages,
- struct page **p)
-{
- int ret;
-
- down_write(&current->mm->mmap_sem);
-
- ret = __ipath_get_user_pages(start_page, num_pages, p, NULL);
-
- up_write(&current->mm->mmap_sem);
-
- return ret;
-}
-
void ipath_release_user_pages(struct page **p, size_t num_pages)
{
down_write(&current->mm->mmap_sem);
--
1.8.1.4


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