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authorDan Williams <dan.j.williams@intel.com>2016-01-15 16:56:49 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-15 17:56:32 -0800
commit5c2c2587b13235bf8b5c9027589f22eff68bdf49 (patch)
tree718d85e1921e2d408bb207261f3000a286815aaa /drivers/nvdimm
parent468ded03c07e0f2b5f05332bc255add47b1b0dee (diff)
mm, dax, pmem: introduce {get|put}_dev_pagemap() for dax-gup
get_dev_page() enables paths like get_user_pages() to pin a dynamically mapped pfn-range (devm_memremap_pages()) while the resulting struct page objects are in use. Unlike get_page() it may fail if the device is, or is in the process of being, disabled. While the initial lookup of the range may be an expensive list walk, the result is cached to speed up subsequent lookups which are likely to be in the same mapped range. devm_memremap_pages() now requires a reference counter to be specified at init time. For pmem this means moving request_queue allocation into pmem_alloc() so the existing queue usage counter can track "device pages". ZONE_DEVICE pages always have an elevated count and will never be on an lru reclaim list. That space in 'struct page' can be redirected for other uses, but for safety introduce a poison value that will always trip __list_add() to assert. This allows half of the struct list_head storage to be reclaimed with some assurance to back up the assumption that the page count never goes to zero and a list_add() is never attempted. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Logan Gunthorpe <logang@deltatee.com> Cc: Dave Hansen <dave@sr71.net> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/nvdimm')
-rw-r--r--drivers/nvdimm/pmem.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 328173d7e1ac..7edf31671dab 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -184,7 +184,7 @@ static struct pmem_device *pmem_alloc(struct device *dev,
pmem->pfn_flags = PFN_DEV;
if (pmem_should_map_pages(dev)) {
pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, res,
- NULL);
+ &q->q_usage_counter, NULL);
pmem->pfn_flags |= PFN_MAP;
} else
pmem->virt_addr = (void __pmem *) devm_memremap(dev,
@@ -365,6 +365,7 @@ static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
struct vmem_altmap *altmap;
struct nd_pfn_sb *pfn_sb;
struct pmem_device *pmem;
+ struct request_queue *q;
phys_addr_t offset;
int rc;
struct vmem_altmap __altmap = {
@@ -406,9 +407,10 @@ static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
/* establish pfn range for lookup, and switch to direct map */
pmem = dev_get_drvdata(dev);
+ q = pmem->pmem_queue;
devm_memunmap(dev, (void __force *) pmem->virt_addr);
pmem->virt_addr = (void __pmem *) devm_memremap_pages(dev, &nsio->res,
- altmap);
+ &q->q_usage_counter, altmap);
pmem->pfn_flags |= PFN_MAP;
if (IS_ERR(pmem->virt_addr)) {
rc = PTR_ERR(pmem->virt_addr);