linux-kernel - [PATCH v2 1/5] drivers/base/memory: Remove unneeded check in remove_memory_block

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Date:   Tue, 25 Jun 2019 09:52:23 +0200
From:   Oscar Salvador <osalvador@...e.de>
To:     akpm@...ux-foundation.org
Cc:     mhocko@...e.com, dan.j.williams@...el.com,
        pasha.tatashin@...een.com, Jonathan.Cameron@...wei.com,
        david@...hat.com, anshuman.khandual@....com, vbabka@...e.cz,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Oscar Salvador <osalvador@...e.de>
Subject: [PATCH v2 1/5] drivers/base/memory: Remove unneeded check in remove_memory_block_devices

remove_memory_block_devices() checks for the range to be aligned
to memory_block_size_bytes, which is our current memory block size,
and WARNs_ON and bails out if it is not.

This is the right to do, but we do already do that in try_remove_memory(),
where remove_memory_block_devices() gets called from, and we even are
more strict in try_remove_memory, since we directly BUG_ON in case the range
is not properly aligned.

Since remove_memory_block_devices() is only called from try_remove_memory(),
we can safely drop the check here.

To be honest, I am not sure if we should kill the system in case we cannot
remove memory.
I tend to think that WARN_ON and return and error is better.

Signed-off-by: Oscar Salvador <osalvador@...e.de>
---
 drivers/base/memory.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 826dd76f662e..07ba731beb42 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -771,10 +771,6 @@ void remove_memory_block_devices(unsigned long start, unsigned long size)
 	struct memory_block *mem;
 	int block_id;

-	if (WARN_ON_ONCE(!IS_ALIGNED(start, memory_block_size_bytes()) ||
-			 !IS_ALIGNED(size, memory_block_size_bytes())))
-		return;
-
 	mutex_lock(&mem_sysfs_mutex);
 	for (block_id = start_block_id; block_id != end_block_id; block_id++) {
 		mem = find_memory_block_by_id(block_id, NULL);
-- 
2.12.3