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| author | Matthew Wilcox (Oracle) <[email protected]> | 2019-07-04 03:21:25 +0000 |
|---|---|---|
| committer | Dan Williams <[email protected]> | 2019-07-17 02:30:59 +0000 |
| commit | 23c84eb7837514e16d79ed6d849b13745e0ce688 (patch) | |
| tree | 001b98406a81d04bb1327949a46a42a71b6c5eb2 /drivers/pci/controller/pci-host-common.c | |
| parent | device-dax: Add a 'resource' attribute (diff) | |
| download | kernel-23c84eb7837514e16d79ed6d849b13745e0ce688.tar.gz kernel-23c84eb7837514e16d79ed6d849b13745e0ce688.zip | |
dax: Fix missed wakeup with PMD faults
RocksDB can hang indefinitely when using a DAX file. This is due to
a bug in the XArray conversion when handling a PMD fault and finding a
PTE entry. We use the wrong index in the hash and end up waiting on
the wrong waitqueue.
There's actually no need to wait; if we find a PTE entry while looking
for a PMD entry, we can return immediately as we know we should fall
back to a PTE fault (which may not conflict with the lock held).
We reuse the XA_RETRY_ENTRY to signal a conflicting entry was found.
This value can never be found in an XArray while holding its lock, so
it does not create an ambiguity.
Cc: <[email protected]>
Link: http://lkml.kernel.org/r/CAPcyv4hwHpX-MkUEqxwdTj7wCCZCN4RV-L4jsnuwLGyL_UEG4A@mail.gmail.com
Fixes: b15cd800682f ("dax: Convert page fault handlers to XArray")
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Tested-by: Dan Williams <[email protected]>
Reported-by: Robert Barror <[email protected]>
Reported-by: Seema Pandit <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
Diffstat (limited to 'drivers/pci/controller/pci-host-common.c')
0 files changed, 0 insertions, 0 deletions