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https://github.com/XTXMarkets/ternfs.git
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6addbdee6a
Initial version really by Pawel, but many changes in between. Big outstanding issues: * span cache reclamation (unbounded memory otherwise...) * bad block service detection and workarounds * corrupted blocks detection and workaround Co-authored-by: Paweł Dziepak <pawel.dziepak@xtxmarkets.com>
25 lines
667 B
C
25 lines
667 B
C
#define ISCSI_POLY 0x82F63B78u
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// Return a(x) multiplied by b(x) modulo ISCSI_POLY, For speed, this requires
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// that a(x) not be zero.
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static u32 crc32c_mult_mod_p(u32 a, u32 b) {
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// m goes from x^0 to x^31
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u32 m = 1u << 31;
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u32 p = 0;
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for (;;) {
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// If a(x) contains x^n, add b(x)*x^n
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if (a & m) {
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p ^= b;
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// Exit when there are no higher bits in a(x)
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if ((a & (m - 1)) == 0) {
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break;
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}
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}
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// Go from x^n to x^(n+1)
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m >>= 1;
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// Go from b(x)*x^n to b(x)*x^(n+1)
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b = (b & 1) ? ((b >> 1) ^ ISCSI_POLY) : b >> 1;
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}
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return p;
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}
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