kmem: don't add __GFP_RECLAIMABLE for KM_VMEM allocations

vmalloc()'d memory is not movable/reclaimable, so __GFP_RECLAIMABLE is
not a valid flag, and since 6.19 the kernel warns if you use it.

Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes openzfs#18107

Author: robn

module/os/linux/spl/spl-kmem-cache.c

@@ -142,8 +142,6 @@ kv_alloc(spl_kmem_cache_t *skc, int size, int flags)
 	gfp_t lflags = kmem_flags_convert(flags | KM_VMEM);
 	void *ptr;
 
-	if (skc->skc_flags & KMC_RECLAIMABLE)
-		lflags |= __GFP_RECLAIMABLE;
 	ptr = spl_vmalloc(size, lflags);
 
 	/* Resulting allocated memory will be page aligned */
@@ -424,7 +422,7 @@ spl_emergency_alloc(spl_kmem_cache_t *skc, int flags, void **obj)
 	if (!empty)
 		return (-EEXIST);
 
-	if (skc->skc_flags & KMC_RECLAIMABLE)
+	if (skc->skc_flags & KMC_RECLAIMABLE && !(flags & KM_VMEM))
 		lflags |= __GFP_RECLAIMABLE;
 	ske = kmalloc(sizeof (*ske), lflags);
 	if (ske == NULL)