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authorDan Williams <dan.j.williams@intel.com>2018-12-28 00:34:57 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 12:11:47 -0800
commita95c90f1e2c253b280385ecf3d4ebfe476926b28 (patch)
tree447d70bd05a99ccfe9c4ca158c9e1b35dda80489 /drivers/dax
parent06489cfbd915ff36c8e36df27f1c2dc60f97ca56 (diff)
downloadlinux-a95c90f1e2c253b280385ecf3d4ebfe476926b28.tar.bz2
mm, devm_memremap_pages: fix shutdown handling
The last step before devm_memremap_pages() returns success is to allocate a release action, devm_memremap_pages_release(), to tear the entire setup down. However, the result from devm_add_action() is not checked. Checking the error from devm_add_action() is not enough. The api currently relies on the fact that the percpu_ref it is using is killed by the time the devm_memremap_pages_release() is run. Rather than continue this awkward situation, offload the responsibility of killing the percpu_ref to devm_memremap_pages_release() directly. This allows devm_memremap_pages() to do the right thing relative to init failures and shutdown. Without this change we could fail to register the teardown of devm_memremap_pages(). The likelihood of hitting this failure is tiny as small memory allocations almost always succeed. However, the impact of the failure is large given any future reconfiguration, or disable/enable, of an nvdimm namespace will fail forever as subsequent calls to devm_memremap_pages() will fail to setup the pgmap_radix since there will be stale entries for the physical address range. An argument could be made to require that the ->kill() operation be set in the @pgmap arg rather than passed in separately. However, it helps code readability, tracking the lifetime of a given instance, to be able to grep the kill routine directly at the devm_memremap_pages() call site. Link: http://lkml.kernel.org/r/154275558526.76910.7535251937849268605.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...") Reviewed-by: "Jérôme Glisse" <jglisse@redhat.com> Reported-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/dax')
-rw-r--r--drivers/dax/pmem.c14
1 files changed, 3 insertions, 11 deletions
diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index 99e2aace8078..2c1f459c0c63 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -48,9 +48,8 @@ static void dax_pmem_percpu_exit(void *data)
percpu_ref_exit(ref);
}
-static void dax_pmem_percpu_kill(void *data)
+static void dax_pmem_percpu_kill(struct percpu_ref *ref)
{
- struct percpu_ref *ref = data;
struct dax_pmem *dax_pmem = to_dax_pmem(ref);
dev_dbg(dax_pmem->dev, "trace\n");
@@ -112,17 +111,10 @@ static int dax_pmem_probe(struct device *dev)
}
dax_pmem->pgmap.ref = &dax_pmem->ref;
+ dax_pmem->pgmap.kill = dax_pmem_percpu_kill;
addr = devm_memremap_pages(dev, &dax_pmem->pgmap);
- if (IS_ERR(addr)) {
- devm_remove_action(dev, dax_pmem_percpu_exit, &dax_pmem->ref);
- percpu_ref_exit(&dax_pmem->ref);
+ if (IS_ERR(addr))
return PTR_ERR(addr);
- }
-
- rc = devm_add_action_or_reset(dev, dax_pmem_percpu_kill,
- &dax_pmem->ref);
- if (rc)
- return rc;
/* adjust the dax_region resource to the start of data */
memcpy(&res, &dax_pmem->pgmap.res, sizeof(res));