sysfs: minimize heap allocations of sysfs paths #797
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11a0918 ("nvme: allow to overwrite base sysfs path") added support for changing the sysfs path via an environment variable. Unfortunately, it added a heap allocation every time a sysfs path was requested. Modify the callers to not free the paths, which allows a string constant to be returned if the path isn't overridden, avoiding an allocation. Cache the path in a static variable so that if it is overridden, the heap-allocated string only needs to be constructed once and afterwards can be reused. Create a file sysfs.c to consolidate this logic instead of spreading them across 3 files. Also introduce a helper to factor out the duplicated code. Fixes: 11a0918 ("nvme: allow to overwrite base sysfs path") Signed-off-by: Caleb Sander Mateos <[email protected]>
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11a0918 ("nvme: allow to overwrite base sysfs path") added support for changing the sysfs path via an environment variable. Unfortunately, it added a heap allocation
every time a sysfs path was requested.
Modify the callers to not free the paths, which allows a string constant to be returned if the path isn't overridden, avoiding an allocation. Cache the path in a static variable so that if it is overridden, the heap-allocated string only needs to be constructed once and afterwards can be reused.
Create a file sysfs.c to consolidate this logic
instead of spreading them across 3 files.
Also introduce a helper to factor out the duplicated code.