Review

Quoted 3 lines

(quoted diff) +1 -1

 	for (prio = ZRAM_SECONDARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
-		kfree(zram->comp_algs[prio]);
+		/* Do not free statically defined compression algorithms */

We probably don't really need this comment.

Review

Quoted 4 lines

(quoted diff) +2 -0

+		if (zram->comp_algs[prio] != default_compressor)
+			kfree(zram->comp_algs[prio]);
 		zram->comp_algs[prio] = NULL;
 	}

OK, so... I wonder how do you get a default_compressor on a non-ZRAM_PRIMARY_COMP prio. May I ask what's your reproducer?

I didn't expect default_compressor on ZRAM_SECONDARY_COMP and below. As far as I can tell, we only do this:

	comp_algorithm_set(zram, ZRAM_PRIMARY_COMP, default_compressor);

in zram_reset_device() and zram_add(). So, how does it end up in ZRAM_SECONDARY_COMP...