mei_cl_fp_by_vtag(9)

💅 mei_cl_fp_by_vtag — the Kernel API Manual, but make it make sense

okay so bestie, you know how the kernel has a whole little MEI client situation going on? this page is mei_cl_fp_by_vtag(9) from the Kernel API Manual, and honestly it's a tiny little function with main character energy. it's literally just "give me the file pointer that matches this vtag." that's the whole vibe. one job. slays.

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✨ NAME ✨

mei_cl_fp_by_vtag — obtain the file pointer by vtag 🎀

like… that's it. that's the function. it obtains the file pointer. by vtag. no cap.

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🌸 SYNOPSIS 🌸

const struct file * mei_cl_fp_by_vtag (const struct mei_cl *cl , u8 vtag
);

look at that signature. const struct file * coming back at you, taking a const struct mei_cl *cl and a u8 vtag. it's giving "small, focused, knows what it wants." we love a function with boundaries 💖

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🦋 ARGUMENTS 🦋

• cl — the host client 💫 this is your const struct mei_cl *, the one whose vtag list we're gonna go rummaging through
• vtag — the virtual tag ⭐ a u8, and it's the thing we're hunting for in that list

two args. both const-friendly-ish. both iconic. periodt.

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🔥 RETURN 🔥

• a file pointer — on success 👑 (const struct file *, exactly like the synopsis promised)
• ERR_PTR(-ENOENT) — if vtag is not found in the client vtag list 💀

so like, real talk: this isn't a "returns NULL on failure" situation. it's an ERR_PTR(-ENOENT) situation. if you're out here checking for NULL only, the vtag was not found and you're gonna have a bad time 😭 check with IS_ERR() like a good little kernel dev, okay? 🫶

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🌈 SEE ALSO 🌈

okay so this is the part where I introduce you to the entire extended friend group. the kernel file is ./drivers/misc/mei/client.c, and here's everyone who's also in the group chat:

• mei_me_cl_init(9), mei_me_cl_get(9), mei_me_cl_release(9), mei_me_cl_put(9)
• __mei_me_cl_del(9), mei_me_cl_del(9), mei_me_cl_add(9)
• __mei_me_cl_by_uuid(9), mei_me_cl_by_uuid(9), mei_me_cl_by_id(9)
• __mei_me_cl_by_uuid_id(9), mei_me_cl_by_uuid_id(9)
• mei_me_cl_rm_by_uuid(9), mei_me_cl_rm_all(9)
• mei_io_cb_free(9), mei_tx_cb_enqueue(9), mei_tx_cb_dequeue(9), mei_cl_set_read_by_fp(9)
• mei_io_cb_init(9), mei_io_list_flush_cl(9), mei_io_tx_list_free_cl(9), mei_io_rd_list_free_fp(9)
• mei_cl_free_pending(9), mei_cl_alloc_cb(9), mei_cl_enqueue_ctrl_wr_cb(9), mei_cl_read_cb(9)
• mei_cl_flush_queues(9), mei_cl_init(9), mei_cl_allocate(9), mei_cl_link(9), mei_cl_unlink(9)
• mei_hbuf_acquire(9), mei_cl_wake_all(9), mei_cl_set_disconnected(9)
• mei_cl_irq_disconnect(9), __mei_cl_disconnect(9), mei_cl_disconnect(9)
• mei_cl_is_other_connecting(9), mei_cl_send_connect(9), mei_cl_irq_connect(9), mei_cl_connect(9)
• mei_cl_alloc_linked(9), mei_cl_tx_flow_ctrl_creds(9), mei_cl_tx_flow_ctrl_creds_reduce(9)
• mei_cl_vtag_alloc(9), mei_cl_reset_read_by_vtag(9), mei_cl_read_vtag_add_fc(9), mei_cl_vt_support_check(9)
• mei_cl_add_rd_completed(9), mei_cl_del_rd_completed(9)
• mei_cl_notify_fop2req(9), mei_cl_notify_req2fop(9), mei_cl_irq_notify(9)
• mei_cl_notify_request(9), mei_cl_notify(9), mei_cl_notify_get(9)
• mei_cl_read_start(9), mei_msg_hdr_init(9), mei_cl_irq_write(9), mei_cl_write(9), mei_cl_complete(9)
• mei_cl_all_disconnect(9), mei_cl_irq_dma_map(9), mei_cl_irq_dma_unmap(9)
• mei_cl_dma_alloc_and_map(9), mei_cl_dma_unmap(9)

no fr, that's the whole roster. every single one. iykyk 💅

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and that's the page bestie 🧚 from ./drivers/misc/mei, dated October 2026, filed under mei_cl_fp_by_vtag(9) — go find your file pointer, you've got this 💜✨