Messages in this thread | | | Date | Mon, 28 Mar 2022 11:15:30 +1100 | Subject | Re: [RESEND PATCH v7 7/8] kernfs: Replace per-fs rwsem with hashed rwsems. | From | Imran Khan <> |
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Hello Al,
On 22/3/22 1:40 pm, Al Viro wrote: [...] > > Sorry, misread that thing - the reason it copies the damn thing at all is > the use of strsep(). Yecch... Rule of the thumb regarding strsep() use, > be it in kernel or in the userland: don't. It's almost never the right > primitive to use. > > Lookups should use qstr; it has both the length and place for hash. > Switch kernfs_find_ns() to that (and lift the calculation of length > into the callers that do not have it - note that kernfs_iop_lookup() > does) and you don't need the strsep() shite (or copying) anymore. >
Regarding using qstr in kernfs_find_ns, do you mean that I should remove ->name and ->hash with a ->qstr in kernfs_node and further modify kernfs_name_compare to make use of qstr.name and qstr.hash.
Also the suggestion about removing buffer copying from kernfs_walk_ns is not clear to me because kernfs_walk_ns invokes kernfs_find_ns with individual path components so we need some mechanism to separate path components.
Sorry if I have missed or misunderstood something in your suggestion.
Thanks, -- Imran
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