devm_request_resource(9)

💅 devm_request_resource(9) 💅

okay so bestie, we're in the <pink>Kernel API Manual</pink> today and this one is a certified baddie of resource management. it's called devm_request_resource(9) and honestly? it's giving "I handle it so you don't have to." ✨

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🌸 NAME 🌸

devm_request_resource — request and reserve an I/O or memory resource 🎀

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✨ SYNOPSIS ✨

int devm_request_resource (struct device *dev , struct resource *root ,
struct resource *new );

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🦋 ARGUMENTS 🦋

• dev — the device you're requesting this resource for. it's literally the main character here 🫶
• root — the root of the resource tree you're requesting the resource from
• new — the descriptor of the resource you want to request. like, the actual thing you're asking for 💅

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💖 DESCRIPTION 💖

okay so picture this: this function is the <hotpink>device-managed</hotpink> version of request_resource. the way that means you usually do NOT need to release resources requested by this function explicitly — because that whole thing gets taken care of automatically when the device is unbound from its driver. automatic cleanup? we love to see it 😭👑

but — and listen, this is the important part — if for some reason you do need to release the resource explicitly (say, because of ordering issues, iykyk), drivers must call devm_release_resource and not the regular release_resource. do not mix those up, bestie, fr fr. 🚨

and when a conflict is detected between any existing resources and the newly requested resource, an error message will be printed. so you'll know. 💀

it returns 0 on success, or a negative error code on failure. periodt. ⭐

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🔥 SEE ALSO 🔥

Kernel file ./kernel/resource.c — go check it out, it's iconic:

request_resource_conflict(9), request_resource(9), release_resource(9), find_next_res(9), walk_iomem_res_desc(9), region_intersects(9), find_resource_space(9), reallocate_resource(9), allocate_resource(9), lookup_resource(9), insert_resource_conflict(9), insert_resource(9), insert_resource_expand_to_fit(9), remove_resource(9), adjust_resource(9), resource_alignment(9), __request_region(9), __release_region(9), release_mem_region_adjustable(9), merge_system_ram_resource(9), devm_release_resource(9), devm_request_free_mem_region(9), alloc_free_mem_region(9) 🌈

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that's the whole thing, bestie, no cap 🧚 this gem lives in the ./kernel source directory and this particular edition is dated <purple>October 2026</purple>. mwah, go reserve some resources responsibly 💜🍓