Nuke single use function PRT_fix_BN() and just use the ATA/ATAPI LBA -> CHS

conversion formula

LBA = (C × HPC + H) × SPT + (S − 1)

instead of the equivalent tortuous arithmetic used in PRT_fix_BN().

No intentional functional change.

diff --git a/sbin/fdisk/cmd.c b/sbin/fdisk/cmd.c
index 71f7496..98aab7a 100644 (file)
--- a/sbin/fdisk/cmd.c
+++ b/sbin/fdisk/cmd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: cmd.c,v 1.149 2022/01/22 15:39:00 krw Exp $   */
+/*     $OpenBSD: cmd.c,v 1.150 2022/01/27 16:26:32 krw Exp $   */
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -191,6 +191,7 @@ int
 edit(const int pn, struct mbr *mbr)
 {
        struct prt              *pp;
+       uint64_t                 track;
        unsigned char            oldid;
 
        pp = &mbr->mbr_prt[pn];
@@ -224,8 +225,13 @@ edit(const int pn, struct mbr *mbr)
                    (pp->prt_scyl == pp->prt_ecyl && pp->prt_shead ==
                    pp->prt_ehead) ? pp->prt_ssect : 1, disk.dk_sectors);
 
-               /* Fix up off/size values */
-               PRT_fix_BN(pp, pn);
+               /* The ATA/ATAPI spec says LBA = (C × HPC + H) × SPT + (S − 1) */
+               track = (uint64_t)pp->prt_scyl * disk.dk_heads + pp->prt_shead;
+               pp->prt_bs = track * disk.dk_sectors + (pp->prt_ssect - 1);
+               track = (uint64_t)pp->prt_ecyl * disk.dk_heads + pp->prt_ehead;
+               pp->prt_ns = track * disk.dk_sectors + (pp->prt_esect - 1) -
+                   pp->prt_bs + 1;
+
                /* Fix up CHS values for LBA */
                PRT_fix_CHS(pp);
        } else {

diff --git a/sbin/fdisk/part.c b/sbin/fdisk/part.c
index 4a7dfa6..b02b6a6 100644 (file)
--- a/sbin/fdisk/part.c
+++ b/sbin/fdisk/part.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: part.c,v 1.112 2022/01/21 17:29:24 krw Exp $  */
+/*     $OpenBSD: part.c,v 1.113 2022/01/27 16:26:32 krw Exp $  */
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -377,38 +377,6 @@ PRT_print_part(const int num, const struct prt *prt, const char *units)
            prt->prt_bs, size, ut->ut_abbr, ascii_id(prt->prt_id));
 }
 
-void
-PRT_fix_BN(struct prt *prt, const int pn)
-{
-       uint32_t                spt, tpc, spc;
-       uint32_t                start = 0;
-       uint32_t                end = 0;
-
-       if (prt->prt_id == DOSPTYP_UNUSED) {
-               memset(prt, 0, sizeof(*prt));
-               return;
-       }
-
-       spt = disk.dk_sectors;
-       tpc = disk.dk_heads;
-       spc = spt * tpc;
-
-       start += prt->prt_scyl * spc;
-       start += prt->prt_shead * spt;
-       start += prt->prt_ssect - 1;
-
-       end += prt->prt_ecyl * spc;
-       end += prt->prt_ehead * spt;
-       end += prt->prt_esect - 1;
-
-       /* XXX - Should handle this... */
-       if (start > end)
-               warnx("Start of partition #%d after end!", pn);
-
-       prt->prt_bs = start;
-       prt->prt_ns = (end - start) + 1;
-}
-
 void
 PRT_fix_CHS(struct prt *prt)
 {

diff --git a/sbin/fdisk/part.h b/sbin/fdisk/part.h
index 97e88d4..e7db6c0 100644 (file)
--- a/sbin/fdisk/part.h
+++ b/sbin/fdisk/part.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: part.h,v 1.32 2022/01/21 17:29:24 krw Exp $   */
+/*     $OpenBSD: part.h,v 1.33 2022/01/27 16:26:32 krw Exp $   */
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -38,8 +38,5 @@ int            PRT_uuid_to_type(const struct uuid *);
 struct uuid    *PRT_type_to_uuid(const int);
 int             PRT_protected_guid(const struct uuid *);
 
-/* This does CHS -> bs/ns */
-void PRT_fix_BN(struct prt *, const int);
-
 /* This does bs/ns -> CHS */
 void PRT_fix_CHS(struct prt *);