Hi Sughosh,
On Thu, 4 Jul 2024 at 08:36, Sughosh Ganu <sughosh.g...@linaro.org> wrote:
>
> Allow for resizing of LMB regions if the region attributes match. The
> current code returns a failure status on detecting an overlapping
> address. This worked up until now since the LMB calls were not
> persistent and global -- the LMB memory map was specific and private
> to a given caller of the LMB API's.
>
> With the change in the LMB code to make the LMB reservations
> persistent, there needs to be a check on whether the memory region can
> be resized, and then do it if so. To distinguish between memory that
> cannot be resized, add a new flag, LMB_NOOVERWRITE. Reserving a region
> of memory with this attribute would indicate that the region cannot be
> resized.
>
> Signed-off-by: Sughosh Ganu <sughosh.g...@linaro.org>
> ---
> Changes since V1:
> * Do the check for the region flags in lmb_resize_regions() and
> lmb_merge_overlap_regions() to decide on merging the overlapping
> regions.
>
> include/lmb.h | 1 +
> lib/lmb.c | 116 ++++++++++++++++++++++++++++++++++++++++++++------
> 2 files changed, 103 insertions(+), 14 deletions(-)
>
> diff --git a/include/lmb.h b/include/lmb.h
> index 069c6af2a3..99fcf5781f 100644
> --- a/include/lmb.h
> +++ b/include/lmb.h
> @@ -20,6 +20,7 @@
> enum lmb_flags {
> LMB_NONE = 0x0,
> LMB_NOMAP = 0x4,
> + LMB_NOOVERWRITE = 0x8,
How about LMB_PERSIST ?
These could be adjusted to use BIT()
> };
>
> /**
> diff --git a/lib/lmb.c b/lib/lmb.c
> index 0d01e58a46..80945e3cae 100644
> --- a/lib/lmb.c
> +++ b/lib/lmb.c
> @@ -230,12 +230,88 @@ void lmb_init_and_reserve_range(phys_addr_t base,
> phys_size_t size,
> lmb_reserve_common(fdt_blob);
> }
>
> +static bool lmb_region_flags_match(struct lmb_region *rgn, unsigned long r1,
At some point the index should change to an int (or uint), rather than
unsigned long. I had a series that did that, but it died.
> + enum lmb_flags flags)
> +{
> + return rgn->region[r1].flags == flags;
> +}
> +
> +static long lmb_merge_overlap_regions(struct lmb_region *rgn, unsigned long
> i,
> + phys_addr_t base, phys_size_t size,
> + enum lmb_flags flags)
> +{
> + phys_size_t rgnsize;
> + unsigned long rgn_cnt, idx;
> + phys_addr_t rgnbase, rgnend;
> + phys_addr_t mergebase, mergeend;
> +
> + rgn_cnt = 0;
> + idx = i;
> + /*
> + * First thing to do is to identify how many regions does
> + * the requested region overlap.
how many regions the requested region overlaps
> + * If the flags match, combine all these overlapping
> + * regions into a single region, and remove the merged
> + * regions.
> + */
> + while (idx < rgn->cnt - 1) {
> + rgnbase = rgn->region[idx].base;
> + rgnsize = rgn->region[idx].size;
> +
> + if (lmb_addrs_overlap(base, size, rgnbase,
> + rgnsize)) {
> + if (!lmb_region_flags_match(rgn, idx, flags))
> + return -1;
> + rgn_cnt++;
> + idx++;
> + }
> + }
> +
> + /* The merged region's base and size */
> + rgnbase = rgn->region[i].base;
> + mergebase = min(base, rgnbase);
> + rgnend = rgn->region[idx].base + rgn->region[idx].size;
> + mergeend = max(rgnend, (base + size));
> +
> + rgn->region[i].base = mergebase;
> + rgn->region[i].size = mergeend - mergebase;
> +
> + /* Now remove the merged regions */
> + while (--rgn_cnt)
> + lmb_remove_region(rgn, i + 1);
> +
> + return 0;
> +}
> +
> +static long lmb_resize_regions(struct lmb_region *rgn, unsigned long i,
> + phys_addr_t base, phys_size_t size,
> + enum lmb_flags flags)
> +{
> + long ret = 0;
> + phys_addr_t rgnend;
> +
> + if (i == rgn->cnt - 1 ||
> + base + size < rgn->region[i + 1].base) {
> + if (!lmb_region_flags_match(rgn, i, flags))
> + return -1;
> +
> + rgnend = rgn->region[i].base + rgn->region[i].size;
> + rgn->region[i].base = min(base, rgn->region[i].base);
> + rgnend = max(base + size, rgnend);
> + rgn->region[i].size = rgnend - rgn->region[i].base;
> + } else {
> + ret = lmb_merge_overlap_regions(rgn, i, base, size, flags);
> + }
> +
> + return ret;
> +}
> +
> /* This routine called with relocation disabled. */
> static long lmb_add_region_flags(struct lmb_region *rgn, phys_addr_t base,
> phys_size_t size, enum lmb_flags flags)
This could really use a function comment
> {
> unsigned long coalesced = 0;
> - long adjacent, i;
> + long ret, i;
>
> if (rgn->cnt == 0) {
> rgn->region[0].base = base;
> @@ -260,23 +336,28 @@ static long lmb_add_region_flags(struct lmb_region
> *rgn, phys_addr_t base,
> return -1; /* regions with new flags */
> }
>
> - adjacent = lmb_addrs_adjacent(base, size, rgnbase, rgnsize);
> - if (adjacent > 0) {
> + ret = lmb_addrs_adjacent(base, size, rgnbase, rgnsize);
> + if (ret > 0) {
> if (flags != rgnflags)
> break;
> rgn->region[i].base -= size;
> rgn->region[i].size += size;
> coalesced++;
> break;
> - } else if (adjacent < 0) {
> + } else if (ret < 0) {
> if (flags != rgnflags)
> break;
> rgn->region[i].size += size;
> coalesced++;
> break;
> } else if (lmb_addrs_overlap(base, size, rgnbase, rgnsize)) {
> - /* regions overlap */
> - return -1;
> + ret = lmb_resize_regions(rgn, i, base, size,
> + flags);
> + if (ret < 0)
> + return -1;
> +
> + coalesced++;
> + break;
> }
> }
>
> @@ -418,7 +499,7 @@ static phys_addr_t lmb_align_down(phys_addr_t addr,
> phys_size_t size)
> }
>
Regards,
Simon
