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| author | Christoph Hellwig <hch@lst.de> | 2017-12-29 08:54:01 +0100 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2018-01-08 11:46:23 -0800 |
| commit | 832d7aa051106c927cae05ced29d3fd31459ed21 (patch) | |
| tree | 72b34c8b3ae395aedaf444246073791ab20ea3c1 /mm/gup.c | |
| parent | 0822acb86cf340cd45b3af6436cec7e3bb24ebd2 (diff) | |
| download | lwn-832d7aa051106c927cae05ced29d3fd31459ed21.tar.gz lwn-832d7aa051106c927cae05ced29d3fd31459ed21.zip | |
mm: optimize dev_pagemap reference counting around get_dev_pagemap
Change the calling convention so that get_dev_pagemap always consumes the
previous reference instead of doing this using an explicit earlier call to
put_dev_pagemap in the callers.
The callers will still need to put the final reference after finishing the
loop over the pages.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'mm/gup.c')
| -rw-r--r-- | mm/gup.c | 7 |
1 files changed, 5 insertions, 2 deletions
@@ -1410,7 +1410,6 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, VM_BUG_ON_PAGE(compound_head(page) != head, page); - put_dev_pagemap(pgmap); SetPageReferenced(page); pages[*nr] = page; (*nr)++; @@ -1420,6 +1419,8 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, ret = 1; pte_unmap: + if (pgmap) + put_dev_pagemap(pgmap); pte_unmap(ptem); return ret; } @@ -1459,10 +1460,12 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr, SetPageReferenced(page); pages[*nr] = page; get_page(page); - put_dev_pagemap(pgmap); (*nr)++; pfn++; } while (addr += PAGE_SIZE, addr != end); + + if (pgmap) + put_dev_pagemap(pgmap); return 1; } |