Hi Andrew
> -----Original Message-----
> From: Andrew Morton [mailto:a...@linux-foundation.org]
> Sent: 2019年2月15日 4:38
> To: Peng Fan <peng....@nxp.com>
> Cc: labb...@redhat.com; mho...@suse.com; vba...@suse.cz;
> iamjoonsoo....@lge.com; r...@linux.vnet.ibm.com;
> m.szyprow...@samsung.com; rdun...@infradead.org;
> andreyk...@google.com; linux...@kvack.org; linux-kernel@vger.kernel.org;
> van.free...@gmail.com; Mike Rapoport <r...@linux.ibm.com>
> Subject: Re: [PATCH] mm/cma: cma_declare_contiguous: correct err handling
>
> On Thu, 14 Feb 2019 12:45:51 +0000 Peng Fan <peng....@nxp.com> wrote:
>
> > In case cma_init_reserved_mem failed, need to free the memblock
> > allocated by memblock_reserve or memblock_alloc_range.
> >
> > ...
> >
> > --- a/mm/cma.c
> > +++ b/mm/cma.c
> > @@ -353,12 +353,14 @@ int __init cma_declare_contiguous(phys_addr_t
> > base,
> >
> > ret = cma_init_reserved_mem(base, size, order_per_bit, name,
> res_cma);
> > if (ret)
> > - goto err;
> > + goto free_mem;
> >
> > pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
> > &base);
> > return 0;
> >
> > +free_mem:
> > + memblock_free(base, size);
> > err:
> > pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> > return ret;
>
> This doesn't look right to me. In the `fixed==true' case we didn't actually
> allocate anything and in the `fixed==false' case, the allocated memory is at
> `addr', not at `base'.
My code base is 5.0.0-rc6, in mm/cma.c
313 /* Reserve memory */
314 if (fixed) {
315 if (memblock_is_region_reserved(base, size) ||
316 memblock_reserve(base, size) < 0) {
317 ret = -EBUSY;
318 goto err;
319 }
320 } else {
When fixed is true, memblock_is_region_reserved will check whether the [base,
base + size)
is reserved, if reserved, return -EBUSY, if not reserved, it will call
memblock_reserve,
if memblock_reserve fail, it will return -EBUSY.
When fixed is false, after memblock_alloc_range, there is one line code `base =
addr;`.
Thanks,
Peng.
