walk_page_mapping(9)

🦋 walk_page_mapping(9) — Kernel API Manual 🦋

okay bestie, welcome to walk_page_mapping(9) — the Kernel API Manual page that's literally all about strolling through every memory area mapped into a struct address_space. It's giving very thorough walk energy, ngl. 💅

🌸 NAME 🌸

walk_page_mapping — walk all memory areas mapped into a struct address_space.

✨ SYNOPSIS ✨

int walk_page_mapping (struct address_space *mapping , pgoff_t
       first_index , pgoff_t nr , const struct mm_walk_ops *ops , void *private
       );

🎀 ARGUMENTS 🎀

• mapping — pointer to the struct address_space. That's the main character of this walk, periodt.
• first_index — first page offset in the address_space.
• nr — number of incremental page offsets to cover. Basically how much of the index range we're visiting.
• ops — operation to call during the walk.
• private — private data for callbacks' usage.

💅 DESCRIPTION 💅

This function walks all memory areas mapped into a struct address_space. The walk is limited to only the given page-size index range, but if the index boundaries cross a huge page-table entry, that entry will be included. So yes, bestie, it can spill a little past the edge when a huge page-table entry is involved — that's intentional, not a glitch. 🫶

Also see walk_page_range for additional information.

Locking tea ☕: this function can't require that the struct mm_struct::mmap_lock is held, since mapping may be mapped by multiple processes. Instead, mapping->i_mmap_rwsem must be held. This might have implications in the callbacks, and it's up to the caller to ensure that the struct mm_struct::mmap_lock is not needed.

Also this means that a caller can't rely on the struct vm_area_struct::vm_flags to be constant across a call, except for immutable flags. Callers requiring this shouldn't use this function. No cap — if you need those flags to stay put, this is not the function for you. 💀

⭐ RETURN ⭐

• 0 on success
• negative error code on failure
• positive number on caller defined premature termination

🌈 SEE ALSO 🌈

• Kernel file ./mm/pagewalk.c
• walk_page_range(9)
• walk_kernel_page_table_range(9)
• walk_page_range_debug(9)
• folio_walk_start(9)

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mwah 💋 that's the whole page, bestie — source/version ./mm, dated October 2026. walk_page_mapping(9) out! 🎀✨