[dm-devel] [PATCH 3/3] dm-integrity: scale down the recalculate buffer if memory allocation fails

[Mikulas Patocka]

If memory allocation fails, try to reduce the size of the recalculate
buffer and continue with the smaller buffer.

Signed-off-by: Mikulas Patocka <mpato...@redhat.com>

---
 drivers/md/dm-integrity.c |   16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

Index: linux-2.6/drivers/md/dm-integrity.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-integrity.c
+++ linux-2.6/drivers/md/dm-integrity.c
@@ -2673,19 +2673,25 @@ static void integrity_recalc(struct work
        unsigned int i;
        int r;
        unsigned int super_counter = 0;
+       unsigned recalc_sectors = RECALC_SECTORS;
 
-       recalc_buffer = __vmalloc(RECALC_SECTORS << SECTOR_SHIFT, GFP_NOIO);
+retry:
+       recalc_buffer = __vmalloc(recalc_sectors << SECTOR_SHIFT, GFP_NOIO);
        if (!recalc_buffer) {
+oom:
+               recalc_sectors >>= 1;
+               if (recalc_sectors >= 1U << ic->sb->log2_sectors_per_block)
+                       goto retry;
                DMCRIT("out of memory for recalculate buffer - recalculation 
disabled");
                goto free_ret;
        }
-       recalc_tags_size = (RECALC_SECTORS >> ic->sb->log2_sectors_per_block) * 
ic->tag_size;
+       recalc_tags_size = (recalc_sectors >> ic->sb->log2_sectors_per_block) * 
ic->tag_size;
        if (crypto_shash_digestsize(ic->internal_hash) > ic->tag_size)
                recalc_tags_size += crypto_shash_digestsize(ic->internal_hash) 
- ic->tag_size;
        recalc_tags = kvmalloc(recalc_tags_size, GFP_NOIO);
        if (!recalc_tags) {
-               DMCRIT("out of memory for recalculate buffer - recalculation 
disabled");
-               goto free_ret;
+               vfree(recalc_buffer);
+               goto oom;
        }
 
        DEBUG_print("start recalculation... (position %llx)\n", 
le64_to_cpu(ic->sb->recalc_sector));
@@ -2708,7 +2714,7 @@ next_chunk:
        }
 
        get_area_and_offset(ic, range.logical_sector, &area, &offset);
-       range.n_sectors = min((sector_t)RECALC_SECTORS, 
ic->provided_data_sectors - range.logical_sector);
+       range.n_sectors = min((sector_t)recalc_sectors, 
ic->provided_data_sectors - range.logical_sector);
        if (!ic->meta_dev)
                range.n_sectors = min(range.n_sectors, ((sector_t)1U << 
ic->sb->log2_interleave_sectors) - (unsigned int)offset);
 
--
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