On Thu, Mar 18, 2021 at 09:00:54PM -0700, Florian Fainelli wrote:
> When SWIOTLB_NO_FORCE is used, there should really be no allocations of
> io_tlb_nslabs to occur since we are not going to use those slabs. If a
> platform was somehow setting swiotlb_no_force and a later call to
> swiotlb_init() was to be made we would still be proceeding with
> allocating the default SWIOTLB size (64MB), whereas if swiotlb=noforce
> was set on the kernel command line we would have only allocated 2KB.
>
> This would be inconsistent and the point of initializing io_tlb_nslabs
> to 1, was to avoid hitting the test for io_tlb_nslabs being 0/not
> initialized.
Could you rebase this on devel/for-linus-5.13 in
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb.git
please?
>
> Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
> ---
> kernel/dma/swiotlb.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index c10e855a03bc..526c8321b76f 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -121,12 +121,10 @@ setup_io_tlb_npages(char *str)
> }
> if (*str == ',')
> ++str;
> - if (!strcmp(str, "force")) {
> + if (!strcmp(str, "force"))
> swiotlb_force = SWIOTLB_FORCE;
> - } else if (!strcmp(str, "noforce")) {
> + else if (!strcmp(str, "noforce"))
> swiotlb_force = SWIOTLB_NO_FORCE;
> - io_tlb_nslabs = 1;
> - }
>
> return 0;
> }
> @@ -284,6 +282,9 @@ swiotlb_init(int verbose)
> unsigned char *vstart;
> unsigned long bytes;
>
> + if (swiotlb_force == SWIOTLB_NO_FORCE)
> + goto out;
> +
> if (!io_tlb_nslabs) {
> io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
> io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
> @@ -302,6 +303,7 @@ swiotlb_init(int verbose)
> io_tlb_start = 0;
> }
> pr_warn("Cannot allocate buffer");
> +out:
> no_iotlb_memory = true;
> }
>
> --
> 2.25.1
>
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