STRUCT SRP_MAP_STATE(9)

💅 struct srp_map_state(9) 💅

okay so this is a page from the Kernel API Manual and it's all about struct srp_map_state — literally the per-request DMA memory mapping state. yes bestie, we're in the infiniband/srp trenches today 🫶

✨ NAME ✨

struct srp_map_state — per-request DMA memory mapping state. that's it, that's the vibe 🎀

🌸 SYNOPSIS 🌸

struct srp_map_state {
    union {
      struct {
        struct srp_fr_desc **next;
        struct srp_fr_desc **end;
      } fr;
      struct {
        void **next;
        void **end;
      } gen;
    };
    struct srp_direct_buf  *desc;
    union {
      u64 *pages;
      struct scatterlist      *sg;
    };
    dma_addr_t base_dma_addr;
    u32 dma_len;
    u32 total_len;
    unsigned int            npages;
    unsigned int            nmdesc;
    unsigned int            ndesc;
 };

no cap, that's the whole struct. two anonymous unions, a desc, a pages/sg union, and a bunch of counters. it's giving "bookkeeping queen" 👑

🦋 Members 🦋

• {unnamed_union} — anonymous. yes literally, it has no name, it's that mysterious 💀
• desc — pointer to the element of the SRP buffer descriptor array that is being filled in rn. main character pointer energy ✨
• {unnamed_union} — anonymous again. another one. we love a mysterious union 🫶
• pages — array with DMA addresses of pages being considered for memory registration. like a little guest list of pages 📋
• base_dma_addr — DMA address of the first page that has not yet been mapped. the "next up" page, lowkey 🎯
• dma_len — number of bytes that will be registered with the next FR memory registration call. the upcoming batch size, fr fr 💫
• total_len — total number of bytes in the sg-list being mapped. the whole entire thing 🌈
• npages — number of page addresses in the pages[] array. count 'em 👀
• nmdesc — number of FR memory descriptors used for mapping. more counting, we stay busy 🧚
• ndesc — number of SRP buffer descriptors that have been filled in. and that's the last counter, periodt 💅

⭐ SEE ALSO ⭐

• Kernel file ./drivers/infiniband/ulp/srp/ib_srp.h — the source file, go read it iykyk 📖
• struct srp_rdma_ch(9)
• struct srp_target_port(9)
• struct srp_fr_desc(9)
• struct srp_fr_pool(9)

go click through those, they're all part of the same friend group honestly 💜

aaaand that's the page!! source is ./drivers/infiniband/ulp/srp, dated October 2026 — mwah, thanks for reading bestie, slay 🎀💖🔥