try_get_locked_pte(9)

🦋 try_get_locked_pte(9) — Kernel API Manual 🦋

okay bestie, so this one is in section 9 of the kernel API manual, and it's genuinely such a vibe once you get it. it's try_get_locked_pte, and it's basically get_locked_pte()'s chill, non-blocking little sibling. let's get into it 💅

✨ NAME ✨

try_get_locked_pte — literally just like get_locked_pte(), except it's atomic and it does a trylock instead of committing to the wait 🫶

🌸 SYNOPSIS 🌸

pte_t * try_get_locked_pte (struct mm_struct *mm , unsigned long vmaddr
, spinlock_t **ptl );

🎀 ARGUMENTS 🎀

• mm — the mm. that's it, that's the whole description, she's mysterious like that ✨
• vmaddr — the userspace virtual address whose pte we're trying to find 👀
• ptl — this gets set to the pointer to the lock that's used to lock the pte, but only in case of success. if it doesn't work out, don't count on it 💀

💖 DESCRIPTION 💖

so this function returns the pointer to the pte corresponding to addr in mm, super similarly to get_locked_pte. but here's where they differ, and it's kind of a big deal: unlike get_locked_pte, no attempt is made to allocate missing page tables. none. zero. not today 🙈

so if a missing or large entry is found, the function just returns NULL. no drama, no allocation, just nope. and if the ptl lock is contended? you get -EAGAIN back, because she's not about to sit around waiting 🔥

in case of success, *ptl will point to the locked pte lock for the returned pte — same behavior as get_locked_pte does, icon behavior honestly 👑

🔒 CONTEXT 🔒

you gotta hold mmap_lock or the vma lock, and it needs to be held for read or for write. non-negotiable bestie, don't skip this one 🫶

⭐ RETURN ⭐

• NULL if the pte cannot be reached.
• -EAGAIN if the pte can be reached, but it just cannot be locked 😭
• the pointer to the pte corresponding to addr in mm, if it can be reached and locked. slay 💅

🌈 SEE ALSO 🌈

kernel file ./arch/s390/mm/gmap_helpers.c, plus these absolute legends:

• gmap_helper_zap_one_page(9)
• gmap_helper_discard(9)
• gmap_helper_try_set_pte_unused(9)
• gmap_helper_disable_cow_sharing(9)

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and that's the whole page, bestie 🎀 brought to you by the fine folks over at ./arch/s390/mm, dated October 2026, from the try_get_locked_pte(9) files — go forth and trylock responsibly 🦋💜