nvme: Fix get-feature on big-endian systems#2888
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igaw merged 1 commit intolinux-nvme:masterfrom Aug 1, 2025
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The `parse_and_open()` function uses `OPT_BYTE` to parse the feature_id and sel options. This means it writes a single byte to the memory locations for `feature_id` and `sel` in the `feat_cfg` struct. However, these fields were declared as `enum`, which typically has the size of an `int`. On big-endian architectures, writing a single byte to the address of an `int` modifies the most significant byte, resulting in an incorrect value being read. This caused the `get-feature` command to fail. The command only worked on little-endian systems. Fix the issue by changing the type for `feature_id` and `sel` to `__u8`. This ensures the fields are treated as single bytes, guaranteeing correct behavior on all architectures. Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
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This bug made nvme/055 blktest fail on big endian archs like s390x |
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Thanks a lot! |
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The
parse_and_open()function usesOPT_BYTEto parse the feature_id and sel options. This means it writes a single byte to the memory locations forfeature_idandselin thefeat_cfgstruct.However, these fields were declared as
enum, which typically has the size of anint. On big-endian architectures, writing a single byte to the address of anintmodifies the most significant byte, resulting in an incorrect value being read. This caused theget-featurecommand to fail. The command only worked on little-endian systems.Fix the issue by changing the type for
feature_idandselto__u8. This ensures the fields are treated as single bytes, guaranteeing correct behavior on all architectures.