Re: [PATCH 3/4] ARM: change vmalloc_min to vmalloc_start

On Tue, May 18, 2021 at 06:32:43PM -0400, Nicolas Pitre wrote:

On Tue, 18 May 2021, Nicolas Pitre wrote:

quoted

On Wed, 19 May 2021, Linus Walleij wrote:

quoted

On Tue, May 18, 2021 at 2:15 PM Russell King (Oracle)
[off-list ref] wrote:

quoted

Change the current vmalloc_min, which is supposed to be the lowest
address of vmalloc space including the VMALLOC_OFFSET, to vmalloc_start
which does not include VMALLOC_OFFSET.

Signed-off-by: Russell King (Oracle) <redacted>

Reviewed-by: Linus Walleij <redacted>

quoted

+static unsigned long __initdata vmalloc_start = VMALLOC_END - (240 << 20);

When I first read this it took me some time to figure out what was
going on here, so if you have time, please fold in a comment
with some explanation of that (240 << 20) thing, in some blog
post I described it as "an interesting way to write 0x0f000000"
but I suppose commit 0536bdf33faf chose this way for a
specific reason? (Paging Nico if he can explain it.)

That's an alternative (and deprecated) way to write MB(240).

And it seems that MB() isn't globally defined either. Oh well.

I could add a patch on the end of the series changing it to 240 * SZ_1M
which will likely be clearer.

-- 
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