"Aneesh Kumar K.V" [off-list ref] writes:

The check against VSID range is implied when we check task size against
hash and radix pgtable range[1], because we make sure page table range cannot
exceed vsid range.

[1] BUILD_BUG_ON(TASK_SIZE_USER64 > H_PGTABLE_RANGE);
BUILD_BUG_ON(TASK_SIZE_USER64 > RADIX_PGTABLE_RANGE);

The check for smaller task size is also removed here, because the follow up
patch will support a tasksize smaller than pgtable range.

Signed-off-by: Aneesh Kumar K.V <redacted>
---
 arch/powerpc/mm/init_64.c    | 4 ----
 arch/powerpc/mm/pgtable_64.c | 5 -----
 2 files changed, 9 deletions(-)

As discussed this has become:

commit f0aceca42796829295f5d20d01d4bee9773b63b7
Author:     Aneesh Kumar K.V [off-list ref]
AuthorDate: Wed Mar 22 09:06:50 2017 +0530
Commit:     Michael Ellerman [off-list ref]
CommitDate: Tue Mar 28 20:28:20 2017 +1100

    powerpc/mm: Remove checks that TASK_SIZE_USER64 is too small
    
    Remove the checks that TASK_SIZE_USER64 is smaller than H_PGTABLE_RANGE
    and USER_VSID_RANGE.
    
    In a following patch we will deliberately add support for a TASK_SIZE
    smaller than both ranges, so this will no longer be an error condition.
    
    Signed-off-by: Aneesh Kumar K.V [off-list ref]
    [mpe: Keep the check in pgtable_64.c that we don't exceed USER_VSID_RANGE]
    Signed-off-by: Michael Ellerman [off-list ref]

diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 9be992083d2a..8f6f2a173e47 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c

@@ -71,10 +71,6 @@
 #if H_PGTABLE_RANGE > USER_VSID_RANGE
 #warning Limited user VSID range means pagetable space is wasted
 #endif
-
-#if (TASK_SIZE_USER64 < H_PGTABLE_RANGE) && (TASK_SIZE_USER64 < USER_VSID_RANGE)
-#warning TASK_SIZE is smaller than it needs to be.
-#endif
 #endif /* CONFIG_PPC_STD_MMU_64 */
 
 phys_addr_t memstart_addr = ~0;

cheers