STRUCT SYNC_FILE(9)

💅 struct sync_file(9) — a Kernel API Manual moment 🎀

okay bestie, we're in the struct sync_file(9) girlie-verse today — this is the kernel API manual page for the little struct that lets you export a sync file to userspace ✨

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🌸 NAME 🌸

struct sync_file — sync file to export to the userspace 💫

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✨ SYNOPSIS ✨

struct sync_file {
    struct file             *file;
    char user_name[32];
  #ifdef CONFIG_DEBUG_FS;
    struct list_head        sync_file_list;
  #endif;
    wait_queue_head_t wq;
    unsigned long           flags;
    struct dma_fence        *fence;
    struct dma_fence_cb cb;
 };

no cap, that's the whole vibe right there 👑 copy it exactly, she's precise 💅

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🦋 Members 🦋

• file — the file representing this fence. lowkey the whole main character of the struct 🫶
• user_name — the name of the sync file, handed to us by userspace — but only for merged fences, bestie. otherwise it's generated through driver callbacks, and in that case the entire array is 0 💀 (yes, literally the whole thing, all zeroes)
• sync_file_list — membership in the global file list 📋 psst: this one's tucked inside the #ifdef CONFIG_DEBUG_FS; so she only shows up when debug fs is in the building 🎀
• wq — wait queue for fence signaling ⏳ this is where everybody waits around for the signal, iconic behavior honestly
• flags — flags for the sync_file 🚩
• fence — fence with the fences in the sync_file 🔥 (yes, fences plural, she contains multitudes)
• cb — fence callback information 📞 the callback deets live here

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🌈 Description 🌈

flags time, bestie: POLL_ENABLED — whether userspace is currently poll'ing or not 👀 that's it, that's the flag. simply asking "are you polling rn?"

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💜 SEE ALSO 💜

• Kernel file ./include/linux/sync_file.h — go read her, iykyk 📖

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and that's a wrap on this one, gorgeous 🌟 this came to you from ./include/linux, dated October 2026, and yes — it's still struct sync_file(9), always and forever 💖🎀🦋