Hi Coly, Thanks for this new version!
On Thu, Dec 02, 2021 at 08:52:40PM +0800, Coly Li wrote: > This patch adds several helper routines to improve badblock ranges > handling. These helper routines will be used later in the improved > version of badblocks_set()/badblocks_clear()/badblocks_check(). > > - Helpers prev_by_hint() and prev_badblocks() are used to find the bad > range from bad table which the searching range starts at or after. > > - The following helpers are to decide the relative layout between the > manipulating range and existing bad block range from bad table. > - can_merge_behind() > Return 'true' if the manipulating range can backward merge with the > bad block range. > - can_merge_front() > Return 'true' if the manipulating range can forward merge with the > bad block range. > - can_combine_front() > Return 'true' if two adjacent bad block ranges before the > manipulating range can be merged. > - overlap_front() > Return 'true' if the manipulating range exactly overlaps with the > bad block range in front of its range. > - overlap_behind() > Return 'true' if the manipulating range exactly overlaps with the > bad block range behind its range. > - can_front_overwrite() > Return 'true' if the manipulating range can forward overwrite the > bad block range in front of its range. > > - The following helpers are to add the manipulating range into the bad > block table. Different routine is called with the specific relative > layout between the maniplating range and other bad block range in the > bad block table. > - behind_merge() > Merge the maniplating range with the bad block range behind its > range, and return the number of merged length in unit of sector. > - front_merge() > Merge the maniplating range with the bad block range in front of > its range, and return the number of merged length in unit of sector. > - front_combine() > Combine the two adjacent bad block ranges before the manipulating > range into a larger one. > - front_overwrite() > Overwrite partial of whole bad block range which is in front of the > manipulating range. The overwrite may split existing bad block range > and generate more bad block ranges into the bad block table. > - insert_at() > Insert the manipulating range at a specific location in the bad > block table. > > All the above helpers are used in later patches to improve the bad block > ranges handling for badblocks_set()/badblocks_clear()/badblocks_check(). > > Signed-off-by: Coly Li <[email protected]> > Cc: Dan Williams <[email protected]> > Cc: Geliang Tang <[email protected]> > Cc: Hannes Reinecke <[email protected]> > Cc: Jens Axboe <[email protected]> > Cc: NeilBrown <[email protected]> > Cc: Vishal L Verma <[email protected]> > --- > block/badblocks.c | 374 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 374 insertions(+) > > diff --git a/block/badblocks.c b/block/badblocks.c > index d39056630d9c..e216c6791b4b 100644 > --- a/block/badblocks.c > +++ b/block/badblocks.c > @@ -16,6 +16,380 @@ > #include <linux/types.h> > #include <linux/slab.h> > > +/* > + * Find the range starts at-or-before 's' from bad table. The search > + * starts from index 'hint' and stops at index 'hint_end' from the bad > + * table. > + */ > +static int prev_by_hint(struct badblocks *bb, sector_t s, int hint) > +{ > + int hint_end = hint + 2; > + u64 *p = bb->page; > + int ret = -1; > + > + while ((hint < hint_end) && ((hint + 1) <= bb->count) && > + (BB_OFFSET(p[hint]) <= s)) { > + if ((hint + 1) == bb->count || BB_OFFSET(p[hint + 1]) > s) { > + ret = hint; > + break; > + } > + hint++; > + } > + > + return ret; > +} > + > +/* > + * Find the range starts at-or-before bad->start. If 'hint' is provided > + * (hint >= 0) then search in the bad table from hint firstly. It is > + * very probably the wanted bad range can be found from the hint index, > + * then the unnecessary while-loop iteration can be avoided. > + */ > +static int prev_badblocks(struct badblocks *bb, struct badblocks_context > *bad, > + int hint) > +{ > + sector_t s = bad->start; > + int ret = -1; > + int lo, hi; > + u64 *p; > + > + if (!bb->count) > + goto out; > + > + if (hint >= 0) { > + ret = prev_by_hint(bb, s, hint); > + if (ret >= 0) > + goto out; > + } > + > + lo = 0; > + hi = bb->count; > + p = bb->page; > + > + while (hi - lo > 1) { > + int mid = (lo + hi)/2; > + sector_t a = BB_OFFSET(p[mid]); > + > + if (a <= s) > + lo = mid; > + else > + hi = mid; > + } > + > + if (BB_OFFSET(p[lo]) <= s) > + ret = lo; > +out: > + return ret; > +} > + > +/* > + * Return 'true' if the range indicated by 'bad' can be backward merged > + * with the bad range (from the bad table) index by 'behind'. > + */ > +static bool can_merge_behind(struct badblocks *bb, struct badblocks_context > *bad, > + int behind) > +{ > + sector_t sectors = bad->len; > + sector_t s = bad->start; > + int ack = bad->ack; The local variables 'sectors' and 'ack' only be used once in this fuction, how about using 'bad->len' and 'bad->ack' directly. > + u64 *p = bb->page; > + > + if ((s <= BB_OFFSET(p[behind])) && > + ((s + sectors) >= BB_OFFSET(p[behind])) && > + ((BB_END(p[behind]) - s) <= BB_MAX_LEN) && > + BB_ACK(p[behind]) == ack) > + return true; > + return false; > +} > + > +/* > + * Do backward merge for range indicated by 'bad' and the bad range > + * (from the bad table) indexed by 'behind'. The return value is merged > + * sectors from bad->len. > + */ > +static int behind_merge(struct badblocks *bb, struct badblocks_context *bad, > + int behind) > +{ > + sector_t sectors = bad->len; > + sector_t s = bad->start; > + int ack = bad->ack; The local variable 'ack' can be dropped too. > + u64 *p = bb->page; > + int merged = 0; > + > + WARN_ON(s > BB_OFFSET(p[behind])); > + WARN_ON((s + sectors) < BB_OFFSET(p[behind])); > + > + if (s < BB_OFFSET(p[behind])) { > + WARN_ON((BB_LEN(p[behind]) + merged) >= BB_MAX_LEN); > + > + merged = min_t(sector_t, sectors, BB_OFFSET(p[behind]) - s); > + p[behind] = BB_MAKE(s, BB_LEN(p[behind]) + merged, ack); > + } else { > + merged = min_t(sector_t, sectors, BB_LEN(p[behind])); > + } > + > + WARN_ON(merged == 0); > + > + return merged; > +} > + > +/* > + * Return 'true' if the range indicated by 'bad' can be forward > + * merged with the bad range (from the bad table) indexed by 'prev'. > + */ > +static bool can_merge_front(struct badblocks *bb, int prev, > + struct badblocks_context *bad) > +{ > + sector_t s = bad->start; > + int ack = bad->ack; The local variable 'ack' here can be dropped too. > + u64 *p = bb->page; > + > + if (BB_ACK(p[prev]) == ack && > + (s < BB_END(p[prev]) || > + (s == BB_END(p[prev]) && (BB_LEN(p[prev]) < BB_MAX_LEN)))) > + return true; > + return false; > +} > + > +/* > + * Do forward merge for range indicated by 'bad' and the bad range > + * (from bad table) indexed by 'prev'. The return value is sectors > + * merged from bad->len. > + */ > +static int front_merge(struct badblocks *bb, int prev, struct > badblocks_context *bad) > +{ > + sector_t sectors = bad->len; > + sector_t s = bad->start; > + int ack = bad->ack; The local variable 'ack' here can be dropped too. > + u64 *p = bb->page; > + int merged = 0; > + > + WARN_ON(s > BB_END(p[prev])); > + > + if (s < BB_END(p[prev])) { > + merged = min_t(sector_t, sectors, BB_END(p[prev]) - s); > + } else { > + merged = min_t(sector_t, sectors, BB_MAX_LEN - BB_LEN(p[prev])); > + if ((prev + 1) < bb->count && > + merged > (BB_OFFSET(p[prev + 1]) - BB_END(p[prev]))) { > + merged = BB_OFFSET(p[prev + 1]) - BB_END(p[prev]); > + } > + > + p[prev] = BB_MAKE(BB_OFFSET(p[prev]), > + BB_LEN(p[prev]) + merged, ack); > + } > + > + return merged; > +} > + > +/* > + * 'Combine' is a special case which can_merge_front() is not able to > + * handle: If a bad range (indexed by 'prev' from bad table) exactly > + * starts as bad->start, and the bad range ahead of 'prev' (indexed by > + * 'prev - 1' from bad table) exactly ends at where 'prev' starts, and > + * the sum of their lengths does not exceed BB_MAX_LEN limitation, then > + * these two bad range (from bad table) can be combined. > + * > + * Return 'true' if bad ranges indexed by 'prev' and 'prev - 1' from bad > + * table can be combined. > + */ > +static bool can_combine_front(struct badblocks *bb, int prev, > + struct badblocks_context *bad) > +{ > + u64 *p = bb->page; > + > + if ((prev > 0) && > + (BB_OFFSET(p[prev]) == bad->start) && > + (BB_END(p[prev - 1]) == BB_OFFSET(p[prev])) && > + (BB_LEN(p[prev - 1]) + BB_LEN(p[prev]) <= BB_MAX_LEN) && > + (BB_ACK(p[prev - 1]) == BB_ACK(p[prev]))) > + return true; > + return false; > +} > + > +/* > + * Combine the bad ranges indexed by 'prev' and 'prev - 1' (from bad > + * table) into one larger bad range, and the new range is indexed by > + * 'prev - 1'. > + */ > +static void front_combine(struct badblocks *bb, int prev) > +{ > + u64 *p = bb->page; > + > + p[prev - 1] = BB_MAKE(BB_OFFSET(p[prev - 1]), > + BB_LEN(p[prev - 1]) + BB_LEN(p[prev]), > + BB_ACK(p[prev])); > + if ((prev + 1) < bb->count) > + memmove(p + prev, p + prev + 1, (bb->count - prev - 1) * 8); > +} > + > +/* > + * Return 'true' if the range indicated by 'bad' is exactly forward > + * overlapped with the bad range (from bad table) indexed by 'front'. > + * Exactly forward overlap means the bad range (from bad table) indexed > + * by 'prev' does not cover the whole range indicated by 'bad'. > + */ > +static bool overlap_front(struct badblocks *bb, int front, > + struct badblocks_context *bad) > +{ > + u64 *p = bb->page; > + > + if (bad->start >= BB_OFFSET(p[front]) && > + bad->start < BB_END(p[front])) > + return true; > + return false; > +} > + > +/* > + * Return 'true' if the range indicated by 'bad' is exactly backward > + * overlapped with the bad range (from bad table) indexed by 'behind'. > + */ > +static bool overlap_behind(struct badblocks *bb, struct badblocks_context > *bad, > + int behind) > +{ > + u64 *p = bb->page; > + > + if (bad->start < BB_OFFSET(p[behind]) && > + (bad->start + bad->len) > BB_OFFSET(p[behind])) > + return true; > + return false; > +} > + > +/* > + * Return 'true' if the range indicated by 'bad' can overwrite the bad > + * range (from bad table) indexed by 'prev'. > + * > + * The range indicated by 'bad' can overwrite the bad range indexed by > + * 'prev' when, > + * 1) The whole range indicated by 'bad' can cover partial or whole bad > + * range (from bad table) indexed by 'prev'. > + * 2) The ack value of 'bad' is larger or equal to the ack value of bad > + * range 'prev'. > + * > + * If the overwriting doesn't cover the whole bad range (from bad table) > + * indexed by 'prev', new range might be split from existing bad range, > + * 1) The overwrite covers head or tail part of existing bad range, 1 > + * extra bad range will be split and added into the bad table. > + * 2) The overwrite covers middle of existing bad range, 2 extra bad > + * ranges will be split (ahead and after the overwritten range) and > + * added into the bad table. > + * The number of extra split ranges of the overwriting is stored in > + * 'extra' and returned for the caller. > + */ > +static bool can_front_overwrite(struct badblocks *bb, int prev, > + struct badblocks_context *bad, int *extra) > +{ > + u64 *p = bb->page; > + int len; > + > + WARN_ON(!overlap_front(bb, prev, bad)); > + > + if (BB_ACK(p[prev]) >= bad->ack) > + return false; > + > + if (BB_END(p[prev]) <= (bad->start + bad->len)) { > + len = BB_END(p[prev]) - bad->start; > + if (BB_OFFSET(p[prev]) == bad->start) > + *extra = 0; > + else > + *extra = 1; > + > + bad->len = len; > + } else { > + if (BB_OFFSET(p[prev]) == bad->start) > + *extra = 1; > + else > + /* > + * prev range will be split into two, beside the overwritten > + * one, an extra slot needed from bad table. > + */ > + *extra = 2; > + } > + > + if ((bb->count + (*extra)) >= MAX_BADBLOCKS) > + return false; > + > + return true; > +} > + > +/* > + * Do the overwrite from the range indicated by 'bad' to the bad range > + * (from bad table) indexed by 'prev'. > + * The previously called can_front_overwrite() will provide how many > + * extra bad range(s) might be split and added into the bad table. All > + * the splitting cases in the bad table will be handled here. > + */ > +static int front_overwrite(struct badblocks *bb, int prev, > + struct badblocks_context *bad, int extra) > +{ > + u64 *p = bb->page; > + sector_t orig_end = BB_END(p[prev]); > + int orig_ack = BB_ACK(p[prev]); How about renaming 'orig_end' to 'end', renaming 'orig_ack' to 'ack'? > + int n = extra; I think no need to add this local variable 'n' here, use 1 or 2 instead. > + > + switch (extra) { > + case 0: > + p[prev] = BB_MAKE(BB_OFFSET(p[prev]), BB_LEN(p[prev]), > + bad->ack); > + break; > + case 1: > + if (BB_OFFSET(p[prev]) == bad->start) { > + p[prev] = BB_MAKE(BB_OFFSET(p[prev]), > + bad->len, bad->ack); > + memmove(p + prev + 2, p + prev + 1, > + (bb->count - prev - 1) * 8); > + p[prev + 1] = BB_MAKE(bad->start + bad->len, > + orig_end - BB_END(p[prev]), > + orig_ack); > + } else { > + p[prev] = BB_MAKE(BB_OFFSET(p[prev]), > + bad->start - BB_OFFSET(p[prev]), > + BB_ACK(p[prev])); > + memmove(p + prev + 1 + n, p + prev + 1, Here use 'p + prev + 2' instead of 'p + prev + 1 + n', > + (bb->count - prev - 1) * 8); > + p[prev + 1] = BB_MAKE(bad->start, bad->len, bad->ack); > + } > + break; > + case 2: > + p[prev] = BB_MAKE(BB_OFFSET(p[prev]), > + bad->start - BB_OFFSET(p[prev]), > + BB_ACK(p[prev])); > + memmove(p + prev + 1 + n, p + prev + 1, And here use 'p + prev + 3' instead of 'p + prev + 1 + n'. > + (bb->count - prev - 1) * 8); > + p[prev + 1] = BB_MAKE(bad->start, bad->len, bad->ack); > + p[prev + 2] = BB_MAKE(BB_END(p[prev + 1]), > + orig_end - BB_END(p[prev + 1]), > + BB_ACK(p[prev])); > + break; > + default: > + break; > + } > + > + return bad->len; > +} > + > +/* > + * Explicitly insert a range indicated by 'bad' to the bad table, where > + * the location is indexed by 'at'. > + */ > +static int insert_at(struct badblocks *bb, int at, struct badblocks_context > *bad) > +{ > + sector_t sectors = bad->len; > + sector_t s = bad->start; > + int ack = bad->ack; The local variables 'sectors', 's' and 'ack' can be dropped here. > + u64 *p = bb->page; > + int len; > + > + WARN_ON(badblocks_full(bb)); > + > + len = min_t(sector_t, sectors, BB_MAX_LEN); > + if (at < bb->count) > + memmove(p + at + 1, p + at, (bb->count - at) * 8); > + p[at] = BB_MAKE(s, len, ack); > + > + return len; > +} > + > /** > * badblocks_check() - check a given range for bad sectors > * @bb: the badblocks structure that holds all badblock > information > -- > 2.31.1 >
