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Date:   Tue, 16 May 2023 09:48:32 +0300
From:   Mike Rapoport <rppt@kernel.org>
To:     Baoquan He <bhe@redhat.com>
Cc:     linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
        linux-mm@kvack.org, arnd@arndb.de, christophe.leroy@csgroup.eu,
        hch@infradead.org, agordeev@linux.ibm.com,
        wangkefeng.wang@huawei.com, schnelle@linux.ibm.com,
        David.Laight@aculab.com, shorne@gmail.com, willy@infradead.org,
        deller@gmx.de
Subject: Re: [PATCH v5 RESEND 06/17] mm/ioremap: add slab availability
 checking in ioremap_prot
Message-ID: <ZGMnQBD6p1s/QKI0@kernel.org>
References: <20230515090848.833045-1-bhe@redhat.com>
 <20230515090848.833045-7-bhe@redhat.com>
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On Mon, May 15, 2023 at 05:08:37PM +0800, Baoquan He wrote:
> Several architectures has done checking if slab if available in
> ioremap_prot(). In fact it should be done in generic ioremap_prot()
> since on any architecutre, slab allocator must be available before
> get_vm_area_caller() and vunmap() are used.
> 
> Add the checking into generic_ioremap_prot().
> 
> Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> Signed-off-by: Baoquan He <bhe@redhat.com>

Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
>  mm/ioremap.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/mm/ioremap.c b/mm/ioremap.c
> index 9f34a8f90b58..2fbe6b9bc50e 100644
> --- a/mm/ioremap.c
> +++ b/mm/ioremap.c
> @@ -18,6 +18,10 @@ void __iomem *generic_ioremap_prot(phys_addr_t phys_addr, size_t size,
>  	phys_addr_t last_addr;
>  	struct vm_struct *area;
>  
> +	/* An early platform driver might end up here */
> +	if (!slab_is_available())
> +		return NULL;
> +
>  	/* Disallow wrap-around or zero size */
>  	last_addr = phys_addr + size - 1;
>  	if (!size || last_addr < phys_addr)
> -- 
> 2.34.1
> 
> 

-- 
Sincerely yours,
Mike.