STRUCT CXL_REGION_PARAMS(9)

💅 struct cxl_region_params(9) 💅

okay bestie so this is a page from the Kernel API Manual (section 9, kernel API gang 🌸) and it's literally all about struct cxl_region_params — the little vibe-holder for region settings ✨

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🎀 NAME 🎀

struct cxl_region_params — region settings, that's it, that's the whole thing 💖

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✨ SYNOPSIS ✨

struct cxl_region_params {
    enum cxl_config_state state;
    uuid_t uuid;
    int interleave_ways;
    int interleave_granularity;
    struct resource *res;
    struct cxl_endpoint_decoder *targets[CXL_DECODER_MAX_INTERLEAVE];
    int nr_targets;
    resource_size_t cache_size;
 };

no cap, that's the whole struct, copied exactly, i don't play about accuracy 🫶

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🦋 Members 🦋

• state — this one lets the driver lockdown any further parameter changes 👑 like it's the bouncer at the club, nobody gets in after this
• uuid — the unique id for persistent regions, its literal main character identifier 💫
• interleave_ways — the number of endpoints in the region, i.e. how many besties are sharing the stripe
• interleave_granularity — the capacity each endpoint contributes to a stripe, so like how much each one's bringing to the picnic basket 🧺
• res — the allocated iomem capacity for this region, the actual resources, the bag 💰
• targets — the active ordered targets in the current decoder configuration — ordered, okay, the order matters, don't come at me 🙈
• nr_targets — number of targets, simply the count, that's it, lowkey the easiest member here
• cache_size — the extended linear cache size if it exists, otherwise zero 🍓 (yes, zero, not "undefined", not "we'll see" — zero)

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💜 Description 💜

okay so the important bit: state transitions are protected by cxl_rwsem.region 🔒

like, if you're touching state, that's the lock, respect the lock, the lock is iconic and you do not cross it periodt 💅

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🌈 SEE ALSO 🌈

Kernel file ./drivers/cxl/cxl.h — and then the whole extended friend group, fr fr:

• cxl objects(9)
• struct cxl_decoder(9)
• struct cxl_endpoint_decoder(9)
• struct cxl_switch_decoder(9)
• struct cxl_rd_ops(9)
• struct cxl_root_decoder(9)
• struct cxl_region(9)
• struct cxl_port(9)
• struct cxl_root(9)
• struct cxl_dport(9)
• struct cxl_ep(9)
• struct cxl_region_ref(9)
• struct cxl_endpoint_dvsec_info(9)

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bestie reminder 💀: those SEE ALSO names are literal struct names and page refs — type them exactly, don't get cute with them, i'm begging 🙏

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aaaand that's the page!! this gem lives in ./drivers/cxl and it's dated October 2026 ⭐ signed, sealed, slayed, and shipped with love from your fave kernel-obsessed bestie 🎀💖🧚‍♀️